Hacking the Nissan Leaf EV

An anonymous reader writes "The New York Times is running a story on people hacking the Nissan Leaf electric vehicle. 'Using Mr. Giddings’s home-brewed E.V. fuel-level display, Leaf drivers get the confidence to extend their driving range by 10 percent or more. His gauge, which displays the actual state of charge, reveals that the Leaf dashboard’s "zero bars" display comes on when the battery pack has several miles remaining.' Here's an interesting quote from one of the hackers, Phil Sadow, who was interviewed for the story: 'I don't like the term hacking because it's been portrayed by the media as something evil. To me, hacking is actually very American. Go out to the garage. Take it apart. Make it better.'"

Comments

Better you say?

[BiggerIsBetter]

Perhaps Nissan knows something about their batteries and BMS that he doesn't, and the false zero reading is there to ensure the batteries last as long as they're intended to? Last I heard, you weren't supposed to completely discharge lithium batteries if you wanted to ensure a usefully long service life.

Re:Better you say?

[queazocotal]

Taking cells all the way to 'zero' in a battery is generally a bad plan, it both stresses the cells more - discharging them at high currents at the very end of the discharge is harsh on them, causes extra wear due to deeper cycle life, and risks overdischarging weaker cells in the battery.

Re:Better you say?

[jtownatpunk.net]

It's also probably intended to keep people from running out of juice on the freeway or some other place where it would be dangerous to be unable to move the vehicle. Honestly, if you're down to the last few miles, it's time to recharge.

Re:Better you say?

[vadim_t]

No, you shouldn't with any kind of modern battery.

Li-Ion doesn't like full discharges, and in fact the internal circuitry should make it impossible. Lead-acid will very quickly become unusable if left fully discharged. And for battery packs, full discharge risks cell reversal, which causes damage.

The only case where you should still do that is when there is some sort of internal statistics being kept of how long the battery is estimated to last, which is out of sync with the actual battery.

That's not for any sort of cleaning though. It's just for fixing incorrect estimations of remaining battery time, which causes devices to turn off too soon, or have them fail to shut down nicely before the battery runs out.

Re:Better you say?

[mirix]

Bingo, it's not like the idiot light on a normal car fires *after* it's empty. That sort of defeats the purpose...

Re:Better you say?

[nlogaxx]

Erroneous. Lithium ion cells do not need to be discharged periodically like NiCd and NiMH rechargable cells. Full discharge and recharge cycles on lithium ion cells only serve to shorten its life.

Re:Better you say?

[Fallingwater]

The only case where you should still do that is when there is some sort of internal statistics being kept of how long the battery is estimated to last, which is out of sync with the actual battery.

It's worth noting that even in this case, the cells don't actually go to zero - in LiIon batteries, the circuitry cuts out at about 3V per cell. Lower than that, and damage WILL occur.

Re:Better you say?

[Zocalo]

I too keep hearing conflicting advice on this, but as far as I can tell the underlying truth is what is indicated in the parent's post.

I'm looking at a Canon LP-E4 battery (from a 1 series EOS camera) and it definitely says "Li-ion" on it, and I also have the manual for the camera with me. These are quite intelligent batteries, with very accurate charge remaining indictors, etc. Every now and then they indicate the need for a "calibration charge" to ensure accurate battery life indication, and to quote the manual on the process "After the calibration is completed and the battery is totally drained, it will take a further two hours to recharge the battery fully." At a guess, I get this maybe warning once per year, per battery - and perhaps even less frequently than that.

I've come across this kind of thing on other "high-end" Li-Ion batteries too, including on laptops, a high-end GPS unit and a satellite comms system. I've never seen this kind of thing on cheaper clones, in lower-end devices like phones, or in any other gadgets where the battery might be regarded as disposable once it deteriorates. Unless the battery in question has a means of asking for a calibration charge, or some such, and a charger that has a dedicated mode for doing so, then you should always try and recharge the battery before it fully drains.

Re:Better you say?

[vlm]

I've come across this kind of thing on other "high-end" Li-Ion batteries too, including on laptops, a high-end GPS unit and a satellite comms system. I've never seen this kind of thing on cheaper clones, in lower-end devices like phones, or in any other gadgets where the battery might be regarded as disposable once it deteriorates. Unless the battery in question has a means of asking for a calibration charge, or some such, and a charger that has a dedicated mode for doing so, then you should always try and recharge the battery before it fully drains.

Your perception is its "high end" because it gets you involved in the recalibration process. The cheap ones recalibrate, they just don't let you know, therefore you perceive them as cheaper.

Re:Better you say?

[Smidge204]

This hack doesn't let you use more capacity from the battery. The car WILL NOT LET YOU drive the battery dead - it will shut itself off before you can do any serious damage.

Instead, this hack gives you useful information about how much charge you actually have left. Okay, you got a "Low Battery" warning and you're 5 miles from home. The range indicator and battery level gauge are both gone. Do you try to make it home and risk getting stuck in the middle of the street, or pull over and call a tow truck now? With the external SOC gauge, you are better informed to make that decision.
=Smidge=

Re:Better you say?

[SuricouRaven]

That is only true for ni-cad batteries. You don't see many of those today.

Re:Better you say?

[Zocalo]

Not quite, it seems to be purely cost based to me as I've only ever seen the recalibrate process on more expensive, so called "luxury" or "premium" devices. That's not to say that cheaper ones (or more expensive ones that lack an overt process) are not doing something behind the scenes as well, but I think that is actually quite unlikely in most cases.

It's simple economics; when you are building an expensive device with a reasonable profit margin, then including recalibration circuitry isn't a big deal. When you are designing something on the pile 'em high and sell 'em cheap ethos then margins are much lower and the few bucks extra for the recalibration might make your product more expensive than the competition and result in lost sales.

Then again, it would be perfectly possible to do it behind the scenes; all it would take is to detect when the calibration is required and then quietly let the battery go completely flat before starting the next recharge. That sounds like a recipe for a poor user experience to me though; imagine your laptop's battery is running low and due a calibration recharge, you put it on charge for an for an hour expecting it to be topped up only to find it's still running low when you power it on...

Re:Better you say?

[Aqualung812]

It's simple economics;

No, it isn't so simple. There are many examples of expensive devices requiring many more manual steps because it gives the perception of value. "Mine requires more work because it is such a precision device" seems to be a very common thing.
Sometimes, this is a good thing, because it allows for better control by the end user *IF* they know what they're doing. SLR vs point & shoot, for example.
Other times, it is simply a status thing. For example, I have a solar powered watch that is synced to the atomic clock in Colorado every morning. My watch will always be within 0.5 seconds of actual time. However, a Rolex that costs thousands more doesn't include the solar charging or atomic clock sync will never be as accurate as my watch, and requires more effort. Still, a Rolex has the perception of higher value.

Re:Better you say?

[rickb928]

Depending on the accuracy if the gauge. I've had cars with optimistic and cars with pessimistic gauges. you learn fast.

Re:Better you say?

[mauriceh]

That was the case with NiCAD. NOT Lithium.

Re:Better you say?

[Zocalo]

You're missing my point a bit, I think. I'm not not saying it's a cost of the item vs. status symbol issue, but it's to do with the profit margin on the item vs. the intended usage of the item. You very seldom see a feature added to a device these days if it's not something that is going to help sell units or aid developers somehow. When was the last time you saw an advert or even a spec. list that put "battery calibration" up there with things like OS, screen/sensor resolution, processor speed/type, storage/memory capacity, etc.?

All of the items I cited have a reason why an accurate battery life indication is desirable, if not essential [*], and the additional cost of adding in calibration is worth while. If there is no specific requirement for a feature, then you don't generally add in the extra circuitry for negligable benefit at extra cost to be passed onto the end user. I'd be interested to hear of any major exceptions though, whether to do with battery calibration (especially if done behind the scenes) or otherwise.

[*] The GPS & SatComm unit both have S&R applications, if you've ever been running low on a camera battery in the closing minutes of a game, you'll know whay that matters to pros, and the laptop, well, let's just say it's "ruggedised" and leave it at that.

Re:Better you say?

[spire3661]

Apple explicitly states on their website that you should full drain your iDevices every once in a while.

Re:Better you say?

[trum4n]

You are 100% correct. I'm sure i could push that pack nearly 175% as far as they spec it, but it would never do it again. The proper maximum depth of charge for such a pack is 80%. Going to 80% every day, you will not get 1000 charges out of most. Going to 60, the life is GREATLY extended. Lead Acid can't take 60%, 50% being the recommended DOC.

Re:Better you say?

[fast turtle]

No, you shouldn't with any kind of modern battery.

Except that's a recomended procedure with Ni-Cad based batteries to help clear the Memory Effect. I suspect that Nissan will deny any warranty replacement of the Leafs battery pack if they detect this software hack because it could have been the cause of the failure and don't forget, Nissan has deeper pockets then us and will fight.

Re:Better you say?

[Qzukk]

Figuring it out would be easier if the gauges were linear. I get around 300 miles to a tank and can regularly hit 180-200 miles before the needle hits the 1/2 mark.

Re:Better you say?

[vadim_t]

A few things:

1. Nobody uses Ni-Cad anymore. It's poisonous and low capacity, the only point in still using it is very high current applications, and even there people mostly use Li-Ion/LiPo these days. Modern usage is very limited.

2. The memory effect was something observed in satellites, which have extremely regular charge and discharge patterns for years on end. You're not going to do the same thing to your mp3 player. It's also specific to one kind of Ni-Cad and not all of them.

3. What you can cure with a deep discharge is voltage depression, which is caused by overcharging. It's not a form of maintenance, as it damages the battery. It's a fix for something that shouldn't have happened in the first place. Get a good charger instead.

Re:Better you say?

[dontmakemethink]

It's kinda like starving yourself until your doctor is ready to pull the plug to save on groceries.

Re:Better you say?

[DerekLyons]

Perhaps Nissan knows something about their batteries and BMS that he doesn't, and the false zero reading is there to ensure the batteries last as long as they're intended to?

There's other possibilities too... Maybe there's an oddity in the discharge curve right near the bottom, or in the capacity reading right near the bottom, or the metering system isn't quite 100% reliable near the bottom...
 
I don't care what kind of engineer you are, if you don't have the fulls specs and know all of the considerations taken and tradeoffs made by the original designers - you're just guessing.
 
Hacking a $1000 computer or a $100 RC airplane is one thing. Hacking (and possibly voiding the warranty and your insurance) on a $25,000 automobile... not something I'd want to guess on.

Re:Better you say?

[Relayman]

[citation needed]

Re:Better you say?

[errandum]

"Standard Maintenance
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month. Need a reminder? Add an event to your desktop’s iCal. When your battery no longer holds sufficient charge to meet your needs, you may choose to replace it. If your notebook came with a built-in battery, you should have the battery replaced only by an Apple Authorized Service Provider."

Those bastards at apple, trying to ruin the battery they'll replace for free if it goes under 80% on the first 2 years (europe).

Re:Better you say?

[errandum]

Read the replay to the first poster stating this.

Re:Better you say?

[errandum]

As I said before,

http://www.apple.com/batteries/notebooks.html

This is just an example. You SHOULD let the battery reach the end every once in a while. There are more devices that recommend this, and I doubt any company would be trying to ruin a battery that they actually replace for free if it goes under 80%

Re:Better you say?

[Firehed]

http://www.apple.com/batteries/ right sidebar, bottom of the page.

HOWEVER - It does NOT say to do a full battery drain. It says to complete a full charge cycle at least once a month. It's just as valid to use 1/4 of the battery and recharge once a week. The only section that mentions a full discharge says that you shouldn't store devices fully discharged for extended periods of time - but on the flip side, it also says that you shouldn't leave it fully charged all the time either.

Re:Better you say?

[spire3661]

http://www.apple.com/batteries/iphone.html

"Use iPhone Regularly
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down )."

"Use Your iPad Regularly
For proper reporting of the battery’s state of charge, be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)."

Re:Better you say?

[HornWumpus]

There are women in the world that will possibly fuck you because you have a Rolex.

If there is a woman who will possibly fuck you because you have a solar powered, atomic clock synching wristwatch I'm sure another /.er has already wrecked her (knocked her up).

You don't understand status symbols do you? Perhaps you picked a bad example.

Re:Better you say?

[HornWumpus]

You realize that those are smart batteries. What you are talking about is a relatively deep cycle, managed by the on board battery management system in your pack and likely used by the same for battery life monitoring/recalibration. The same system they are talking about fucking with in the Leaf (troubleshooting chart Q1: 'Is it fucked up?' Q2: 'Did you fuck with it').

That said I'm sure there is a safety margin in the firmware in all battery packs. What is safety margin but wasted capacity? Good fun. I'd be fucking with the motor controller and upping main voltages myself. Change the details on the timing and you can double the torque. RC people do it all the time (on cheap motors). Wouldn't call it a success until I broke a half-shaft (drive shaft for foreigners). Do they sell a locking diff for the Leaf?

Re:Better you say?

[rickb928]

When the Explorer is driven right, I get to 3/4 at 100 miles, 1/2 at 200 miles, and 1/4 at 300 miles. At 0%, I have 2 gallons left.

The Saab had a new fuel pump assy put in,and since then it's dead on. A maximum fillup put the gauge at exactly full, and at empty the computer claims I have 30 miles left, a little more than a gallon on the highway. At the bottom of reserve, I can get .5 gallons more than the listed capacity.

Re:Better you say?

[cffrost]

There are women in the world that will possibly fuck you because you have a Rolex.

If a woman is fucking you because of your Rolex, you're probably getting fucked in more ways than one.

Re:Better you say?

[vadim_t]

I find the "keep the electrons moving" language suspicious. Not like they'll get rusty.

Re:Better you say?

[HornWumpus]

I didn't say my Rolex was real. Just a very good copy.

Re:Better you say?

[cffrost]

Well played, Mr. Wumpus... Well played. ;o)

Re:Better you say?

[ScrewMaster]

Perhaps Nissan knows something about their batteries and BMS that he doesn't, and the false zero reading is there to ensure the batteries last as long as they're intended to? Last I heard, you weren't supposed to completely discharge lithium batteries if you wanted to ensure a usefully long service life.

Yes, it's called "deep cycling" and it's something that you don't want to do to pretty much any type of secondary cell.

Re:Better you say?

[Richy_T]

You're missing my point a bit, I think.

This whole thread has got off point.

The fact that it says "totally discharged" in the manual does not mean that the cell has been discharged to zero, merely that it has been discharged as far as the calibration process will take it (or until the safety circuitry kicks in, whichever comes soonest).

Re:Better you say?

[Richy_T]

You cannot full-drain one of these devices without physically disassembling it. There is circuitry to prevent further drain once a certain limit has been reached entirely to protect the battery (and device) from damage.

Re:Better you say?

[ScrewMaster]

http://www.apple.com/batteries/iphone.html "Use iPhone Regularly For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down )." "Use Your iPad Regularly For proper reporting of the battery’s state of charge, be sure to go through at least one charge cycle per month (charging the battery to 100% and then completely running it down)."

"keep the electrons moving." That is so typical of Apple: dumb things down so even a moron will think he understands it.

In any event, as another poster pointed out, that has nothing to do with maximizing the longevity of the battery: in fact, it's going to lessen the total number of charge/discharge cycles that you get. I don't know of any chemical system whereby periodic deep cycling is considered good for the cells (even Ni-Cads: the memory effect is real, but you still don't need to deep cycle the things to prevent that.) This is actually a matter of keeping the battery management system in sync with the battery's actual state of charge, to get more run time before the device thinks the battery is almost dead.

Battery management isn't exactly trivial. It's a hell of a lot easier with a lead-acid battery, since the terminal voltage drops pretty linearly with the state of charge. That's a problem for electronics, since you need a much higher nominal voltage than you actually need and have to regulate it down, or must use a DC-DC converter to maintain a minimum level after the terminal voltage drops below what your equipment needs. Still, it's pretty straightforward to determine how much charge is left.

It's much more complicated with nickel-cadmium, nickel-metal-hydride or lithium-ion cells, since they do not have a linear discharge curve. Ni-Cads, for example, remain damn near flat until near the very end, where the voltage drops suddenly to a lower value for a while before going to zero. If you go beyond that "knee", you will likely damage cells (or in the case of a series pack, drive one or more cells into reverse ... bad news.) On the other hand, that flat discharge curve is great for electronic devices since your terminal voltage stays relatively constant. The problem comes in when trying to figure out how much juice you have left: you have to make an estimate of the amount of energy put in during charging, and how much taken out in operation.

Eventually, your estimate is going to be off. Batteries age and lose capacity, and errors in data acquisition occur. That's a real problem when charging: if you don't know when the pack is fully charged you're going to overcharge it and reduce its lifespan. Consequently, most commercial batteries have a thermistor or other temperature sensor in them which is monitored by battery management: when the battery has reached full charge, any additional charging current comes out as heat. The sudden rise in temperature indicates that the battery is charged.

Re:Better you say?

[Grishnakh]

Most likely, it's either a liability thing, or a "don't piss off the customer" thing.

For instance, I read a story once that many years ago, Cadillac tried to fix its fuel gauges. They did; they made the fuel gauge linear, so the gauge correctly showed the amount of fuel that was left: the 3/4 mark meant 3/4 full, the 1/2 mark meant 1/2 full, and the empty mark really did mean empty. But then customers got really angry: they complained their cars were guzzling gas (!), and that they were running out of gas and having to call tow trucks. So, Cadillac re-engineered their fuel gauges, so that they took a long time to go from Full to 1/2, went really fast from 1/2 down to empty, and then sat on empty for a long time before being truly empty. The complaints stopped.

You can't have a battery level gauge that shows "10 miles left", for instance, where that's really true. There needs to be perhaps another 10 miles in addition. Otherwise, people will run out of battery power because they think they only have 10 miles left to go, when in reality they have another 15.

Re:Better you say?

[ScrewMaster]

A few things:

1. Nobody uses Ni-Cad anymore. It's poisonous and low capacity, the only point in still using it is very high current applications, and even there people mostly use Li-Ion/LiPo these days. Modern usage is very limited.

2. The memory effect was something observed in satellites, which have extremely regular charge and discharge patterns for years on end. You're not going to do the same thing to your mp3 player. It's also specific to one kind of Ni-Cad and not all of them.

3. What you can cure with a deep discharge is voltage depression, which is caused by overcharging. It's not a form of maintenance, as it damages the battery. It's a fix for something that shouldn't have happened in the first place. Get a good charger instead.

The memory effect is an artifact of only using the top few percent of a cell's charge range. The people that use their cordless phones for an hour and then put it back on the charger are the folks that end up complaining about memory. Let the battery run down for a while before you recharge it and you won't see a memory effect.

And, actually, nickel-cadmium batteries are used all over the place to this very day. Most of the remote-controlled toy vehicles you see are Ni-Cad, because they are capable of accepting extremely high charging currents without self-destructing, especially when compared to lithium-ion. That's really handy when you're racing your radio-controlled dune-buggy and need to juice up between events. They are also more robust then lithium ion and can be mistreated more readily, are more stable, and tend not to blow up. They're also used in just about every low-powered wireless device on the planet, such as cordless phones, because you don't need high energy density when you're only transmitting fifty feet.

Re:Better you say?

[Grishnakh]

Not necessarily. Look at Donald Trump, for instance, and his latest wife. She's beautiful enough to be a model, but he's butt-ugly and a lot older than her to boot. There's no way a guy like that would attract a woman like that if it weren't for his money, and the money he spends on her is probably worth it in his mind to have someone that attractive on his arm and in his bed, even if it basically does mean she's a high-priced full-time prostitute. If he had only looked for women that loved him for his intrinsic qualities rather than his wealth, he'd be alone (because honestly, there really isn't much to love there, is there?).

Re:Better you say?

[ScrewMaster]

Otherwise, people will run out of battery power because they think they only have 10 miles left to go, when in reality they have another 15.

It would be interesting to link the battery management firmware with the car's GPS. If it knows where you're going, it could tell you that you can't make it, or give you the option of risking your battery pack to get there.

Re:Better you say?

[Aqualung812]

You don't understand status symbols do you?

No, I just don't want anything to do with anyone who is so enamored with them.

Re:Better you say?

[Grishnakh]

Wouldn't call it a success until I broke a half-shaft (drive shaft for foreigners).

I don't know where you live, but here in the USA, we call those things "CV axles". Go to any American auto parts website and look them up, and that's where you'll find them.

A "drive shaft" is something only used in RWD vehicles, which extends from the transmission to the rear differential.

Re:Better you say?

[dudpixel]

Exactly the same way most petrol/diesel/lpg-fueled cars operate. When the needle hits Empty, you know you've still got 100km worth of fuel left in the tank. If it really was bone dry when the needle hit the Empty mark, we'd have out-of-fuel cars stopped all over the place. Its just human nature to put things off until the last minute.

I'd say this feature on the LEAF uses the same principle.

Re:Better you say?

[adolf]

It's not* good for the cells. But it is good for the charging circuitry and for the battery life display, and therefore the health and usefulness of the entire system (which obviously includes more than just a battery) improves when Apple's simple advice is followed.

The problem is not an occasional (once or twice in a lifetime, or maybe every few months) discharge, but when people take this advice to the obvious partially-informed logical extreme and conclude that frequent complete discharge of batteries is somehow better than not.

The main benefit is as follows: Without at least one "complete" discharge (which still leaves quite a lot more than 0V in the cells), the device has no idea what the actual state of a partially-discharged battery pack ever is. But after a "complete" discharge, the battery life display has at least a fighting chance at being close to correct, which is useful to us humans.

* And in general: It's somewhat damaging to "fully" discharge modern lithium batteries. But then, it's also somewhat damaging to recharge them "fully". Or to discharge/recharge them just a little bit. And it's somewhat damaging to leave them floating on the charger all the time. Or to do anything with them when they're too hot. Or too cold. (Or when the sun is in the West during high tide, etc.)

And it's even somewhat damaging to leave them unused in a box in your desk drawer for long periods.

In other words, every battery has a finite lifespan, especially rechargeable lithium cells: The clock is ticking once they're manufactured. Their capacity varies over time, possibly non-linearly but always asymptotically on a downward slope, no matter how they're used (or not used), and extreme usage simply accelerates that trend.

My advice to rechargeable battery users (for all types of battery and user) is as follows: Don't make a habit out of intentionally deep-discharging the thing, because such a habit does more harm than good (and it will probably happen incidentally now and then, anyway). Charge the thing whenever it's actually convenient, no matter what the battery meter says. And certainly do use the thing on battery power alone whenever that's convenient, because that's what it's for.

Re:Better you say?

[adolf]

Okay, you got a "Low Battery" warning and you're 5 miles from home. The range indicator and battery level gauge are both gone. Do you try to make it home and risk getting stuck in the middle of the street, or pull over and call a tow truck now?

Who here calls for a tow truck when stuck a paltry 5 miles from home?

Seriously. Isn't this what pickup trucks, tow straps, and sons/grandsons/brothers/brothers-in-law/friends + beer bribes are for? I've had cars professionally towed, for sure, but it's always been for much greater distances than that.

It does have hydraulic brakes, doesn't it?

FFS. At 5 miles away, I'd be more inclined to push it into a driveway or a parking lot, ask the nice folks inside the (random) building if I can borrow an outlet for a bit, and maybe offer the homeowner or manager a bit of cash for the trouble.

But more to the point: It's really just a psychological issue. Replacing (or supplementing) a gauge that reads 0 when there's still usable charge left with a gauge that reads (say) 5 just allows for common people to push things even further to the extreme end of things, and likely actually increases the chances of being stuck somewhere instead of reducing them.

Even as an altruist who is in favor of speaking (and receiving) the absolute truth, no matter how ugly it might be, I must say that it's less hazardous to the driver, on average, if the gauge is somewhat pessimistic.

And really: Are we all really so smart here that we must conclude that the other smart people at Nissan didn't already think of this in the delicate and extensive balancing act of creating a car that people actually enjoy owning and driving?

Re:Better you say?

[BiggerIsBetter]

That would be pretty cool. You'd want to include topology in that calculation too, because 10 miles on a flat freeway is very different to 10 miles of mountain road.

Re:Better you say?

[sjames]

He IS a doctor of electrical engineering, he probably thought of that.

I'm guessing that the 12 bar readout goes to zero significantly before the battery pack reaches the low voltage cutoff (which, in turn will include a margin for error to make sure the cells aren't damaged by over discharge). The car doesn't stop dead at zero bars with or without his modification. All he does is provide a readout that more accurately reflects when you will stop dead.

Re:Better you say?

[Pence128]

The reason for this Is that it is quite difficult to measure the state of charge of a battery electronically. All you can know for certain is that (for Li-ion) 4.2V (when charging) is 100% and 3.0V is 0%. What smart batteries do is measure the amount of energy you've taken out of the battery and subtract it from the capacity of the battery. The problem with this is that the capacity changes over its lifetime. What a calibration charge does is completely discharge the battery from 100% to 0%. The microcontroller (yes, your battery actually has its own computer in it) makes a note of how much energy the battery supplied during this period and uses it as the new total capacity.

Re:Better you say?

[Pence128]

The hack is a more accurate charge gauge. The computer can measure the SOC of the battery to within less than 1%, but dumbs it down to a strip of 12 bars. When get to the last bar, all you know is that it's less than 1/12 SOC. You could have anywhere up to 8% left. This tells you exactly how much.

Re:Better you say?

[DerekLyons]

The hack is a more accurate charge gauge.

The hack produces a more *precise* charge gauge, whether or not it is more *accurate* is unknown without considerable engineering work. (And for the reasons discussed below, with 100% certainty it is not more accurate - because you're still relying on the same hardware and software.)
 
Don't confuse precise and accurate, they are not synonyms despite being commonly treated so.
 

The computer can measure the SOC of the battery to within less than 1%, but dumbs it down to a strip of 12 bars.

And, as I said in my original post, there may very well be valid engineering reasons for doing so. A battery charge gauge isn't the equivalent of a fuel gauge as you aren't directly measuring a physical quantity. A battery charge gauge rather is displaying a calculated quantity, a calculation with a significant number of variables. The value of many of those variables cannot themselves be directly measured, and thus can be quite fuzzy. Even if they can be directly measured, that doesn't mean there isn't an element of fuzz there too - measuring devices are only as good as their budget, design, construction, maintenance, and calibration will allow. (And the Leaf isn't built by the people who built the NASA moon rovers. Or even by the people who built the Shuttle.) What this all adds up to, is that while the computer may be able to calculate the SOC with precision, that doesn't mean that the calculated value is accurate because of all the fuzz in the system. (GIGO.)
 
Given that the consequences for the battery (and it's owner) if the battery is run flat - it's an entirely reasonable engineering decision to encourage the owner to (re)charge the battery well before reaching that state.

Re:Better you say?

[Pence128]

Gah, you're entirely correct. Precise, not accurate. I've been trying to train myself to remember the difference, but it's not working.

I made the assumption that (like almost anything with an Li-ion battery) the car computer just passes along the value given by the battery's microcontroller. The microcontroller prevents the battery from being discharged to the point of damage. I don't think this hack will break anything, but I don't like it either. If you need to zoom in to see if you can make it home to charge, you're doing it wrong.

Re:Better you say?

[petermgreen]

AIUI while electric vehicles/hybrids with regenerative breaking are much better in stop and go traffic than vehicles that use an ICE directly the energy used per mile is still highly dependent on driving style and conditions. So even with a GPS it's very difficult to accurately predict whether you will get there or not.

Re:Better you say?

[tlhIngan]

The main benefit is as follows: Without at least one "complete" discharge (which still leaves quite a lot more than 0V in the cells), the device has no idea what the actual state of a partially-discharged battery pack ever is. But after a "complete" discharge, the battery life display has at least a fighting chance at being close to correct, which is useful to us humans.

The reason for the recalibration is simple - the battery gauges work by counting colombs. Cheap devices use a voltage check (simple two-wire battery packs, that are replacable - the third contact's usually a thermistor). The voltage is then compared with a curve to determine state of charge. You can tell this by looking at non-linearities of the battery (e.g., it takes forever to get to 50%, then drops to nothing in 10 minutes sort of deal).

A colomb counter is a bit more reliably, in that it counts (roughly) electrons going into and out of the battery pack. But to offer a good estimate on the battery level, it needs to know how much charge there is. When manufactured, they have a rough level based on battery design, but as they age, that level goes down and the estimate goes off. After 3 years or so, capacity can be reduced by 50+%, so if the colomb counter isn't recalibrated, it'll be off.

The colomb counter also offers an estimate into the life of the battery - when the capacity decreases it can easily signal that the battery has degraded.

Re:Better you say?

[DerekLyons]

Gah, you're entirely correct. Precise, not accurate. I've been trying to train myself to remember the difference, but it's not working.

Not to worry, I get 'em ack basswards all too frequently too...
 

I made the assumption that (like almost anything with an Li-ion battery) the car computer just passes along the value given by the battery's microcontroller. The microcontroller prevents the battery from being discharged to the point of damage.

Regardless of which circuit board is doing the calculations, the issues with calculating SOC are the same. I think your assumption is a safe one however, because it allows the battery pack's design to be altered without having to alter the cars soft- or firm- ware. (And because SOC data needs to be available even when the pack is not installed in a car.)
 

The microcontroller prevents the battery from being discharged to the point of damage. I don't think this hack will break anything, but I don't like it either. If you need to zoom in to see if you can make it home to charge, you're doing it wrong.

On this, we're in complete agreement. Doubly so since how fast that last 1% is going to be consumed is so dependent on outside variables like traffic lights, detours, terrain, etc... Nobody with any sense would drive any distance with less than a quarter of a tank, so doing so with less than an a twelfth of a tank just seems silly.

Re:Better you say?

[Qzukk]

I've only ever had three cars, but all three took longer to reach 1/2 than it did to reach E, though now that I've had the chance to sleep on it, it's possible that the issue is that the "reserve" past the bottom of E would make the distance from 1/2 to E shorter than the distance from F to 1/2.

Re:Better you say?

[Grishnakh]

I wonder if Mazda characterized the fuel tank and used some electronics to make the gauge read linearly, as I explained how to do in another post in this thread.

Of course, the shape of the fuel tank would have a lot to do with this; if the tank is pretty regular, it will read fairly linearly without any electronics to compensate. But if the tank is odd-shaped, it would absolutely need some method of compensating. Perhaps your VW has a really odd-shaped tank. I've never noticed much nonlinearity with my Acura's fuel gauge, and it's from 1994 and definitely doesn't have any special electronics, but the tank itself is a very regular shape.

Re:Better you say?

[Cramer]

Everything on the car is electically powered. Yes, there is a manual "emergency" provision for breaking, but without power to charge the system, you get about the same out of the volt as ANY powered-off vehicle. Try it with you own car; with the engine off, you'll get 2-3 good cycles out of the breaks before you're screwed.

The problem with the "ask some nice folks" route is "for a bit" is actually SEVERAL HOURS. The Top Gear idiots went tooling around in a few; it ended as you would expect from those nuts.

The Volt does exactly what every other car does... zero charge does not mean "dead". Just like "0 miles remaining" in my car does not mean I'm out of gas. (I actually have ~3gal in the tank at that point which is another 100-150miles!)

Re:Better you say?

[HornWumpus]

Anyplace that uses British terminology uses 'propeller shaft' for 'drive shaft' and 'drive shaft' for 'half shaft'

I don't know where you pulled 'CV axles' from (not any American auto parts manual) ? The do contain CV joints.

Re:Better you say?

[Grishnakh]

Check out what Autozone calls them:
http://www.autozone.com/autozone/parts/Drivetrain/_/N-6q74v
Down at the end of the C's, there's "CV axle"

Re:Better you say?

[Smidge204]

The problem is, you don't have any idea how far you can actually drive once you get the low (or "very low") battery warning. It can literally be anywhere from 5 miles to less than a mile depending on your driving habits, weather and traffic conditions, and topology.

Good luck towing the LEAF with a strap or chain - the entire undercarriage is covered in plastic for aerodynamics. Unless you decide to hook up to the suspension arms which is a good way to ruin your alignment. There's also no mechanical neutral so towing the LEAF with the drive wheels on the ground may cause serious damage (so claims the manual, anyway).

And really: Are we all really so smart here that we must conclude that the other smart people at Nissan didn't already think of this in the delicate and extensive balancing act of creating a car that people actually enjoy owning and driving?

The same smart people who designed the heater to draw power even when the climate control is set for A/C (Not to mention the fact the heating system uses coolant and a heater core instead of heating the air directly, requiring a degas tank, pump and hoses)? The same smart people who explicitly designed it so you can NOT set the car to charge immediately upon plug-in by default (you have to hit a button and have 30 seconds to plug in to charge immediately, or trick it by setting both timers a certain, undocumented way)? Not really trying to knock the Nissan engineers but they are only human, and design-by-committee is a hazard for more than just software. There are a lot of little things that have no rhyme or reason for being the way they are. For example, they could easily have added a true SOC reading to the central console display.
=Smidge=

Re:Better you say?

[Smidge204]

Yes, there is a manual "emergency" provision for breaking

Actually there isn't. The parking brake is actually a switch that activates an electric actuator to mechanically clamp the rear wheels. (Add that to the list of stupid design decisions I guess). If you somehow lose ALL electrical power in the LEAF, you have nothing left but normal, un-boosted hydraulic disc brakes.

Though the brake system does have a set of capacitors as the emergency reserve.
=Smidge=

Re:Better you say?

[Cramer]

What I was referring to was the direct hydrolic link between the driver's brake peddle and the actual brakes. Without power, they will still work... for a limited number of pumps. The "park brake" isn't an "emergency brake" -- it isn't intended to do anything but hold the car in place. That said, an E-Brake will not rapidly stop a car; it will slow it to a stop, however, over a much longer distance. (typically only cabled to the rear brakes.)

Re:Better you say?

[mattack2]

Who here calls for a tow truck when stuck a paltry 5 miles from home?

I reconfirmed what I thought -- the limit is 5 miles for the cheapest AAA membership.

(Though I guess I've used it for jump starts and a flat tire most recently, years ago.. I paid for it, why not use it?)

Re:Better you say?

[mattack2]

The same smart people who designed the heater to draw power even when the climate control is set for A/C (Not to mention the fact the heating system uses coolant and a heater core instead of heating the air directly, requiring a degas tank, pump and hoses)?

It sounds like they're doing it this way so that you can have a defroster in the winter. The Car Talk guys have talked about this kind of thing often -- IIRC, you turn the A/C on, but still crank up the temperature.. so you get warm, low humidity air.. Which I think is basically the same thing the 'defrost' setting does automatically.

Re:Better you say?

[adolf]

Hmm.

I keep a set of jumper cables in the trunk. I've only used them to help other people rather than to get my own vehicle(s) going, but I'd guess that they work just as well going the other way. ;)

And I'd so much rather just go turn a wrench and get a tire changed, than wait for someone else. It just takes a few minutes.

AAA? Meh. But to each his own, I guess.

Re:Better you say?

[adolf]

Good luck towing the LEAF with a strap or chain - the entire undercarriage is covered in plastic for aerodynamics. Unless you decide to hook up to the suspension arms which is a good way to ruin your alignment. There's also no mechanical neutral so towing the LEAF with the drive wheels on the ground may cause serious damage (so claims the manual, anyway).

Why not just screw the included recovery hook into the front bumper?

Manuals are often wrong and/or overprotective. I don't expect everyone to be able to get this stuff right, but this is Slashdot, not the editorial section of the local news rag. Towing a Leaf a few miles is no different, electrically, than driving a Leaf down a very long hill.

The same smart people who designed the heater to draw power even when the climate control is set for A/C (Not to mention the fact the heating system uses coolant and a heater core instead of heating the air directly, requiring a degas tank, pump and hoses)?

The heater is commonly active on any car when the AC is in use. Even one with manual controls: Select appropriate vents, turn AC on, adjust fan speed for a comfortable amount of artificial wind, and then add heat using the temperature knob. Doing it this way helps reduce humidity, and allows for effective bi-level cooling.

It's not the same arrangement as a common home HVAC system, but it doesn't have the same requirements either.

As another poster pointed out, the opposite is very useful in cold and/or rainy weather: Using the defroster vent with heat and the AC on (some cars do this irrevocably in the defrost position, while others have a manual switch for the compressor) rapidly removes condensation from the inside of the window glass.

Meanwhile, the Leaf uses water cooling for some of its electronics. As long as this is the case, using the waste heat to warm up the passenger compartment is free, since the pump was already running anyway for cooling purposes.

As to your 30-second song and dance, I think you meant to say that you have 15 minutes to connect the charging cable, at least according to Nissan. Furthermore, if you don't have a schedule set, it charges immediately as soon as you connect it without pushing a button, as long as the car is off.

About the only way to improve on that behavior is to make it telepathic.

And setting up a schedule is pretty plainly documented on page CH-18 of the manual, though it looks rather self-explanatory to me: It's all GUI-based.

Is there anything else that you think the smart folks at Nissan got wrong other than the range indicator (which, as I mentioned previously, I don't think is wrong)?

Re:Better you say?

[adolf]

Everything on the car is electically powered. Yes, there is a manual "emergency" provision for breaking, but without power to charge the system, you get about the same out of the volt as ANY powered-off vehicle. Try it with you own car; with the engine off, you'll get 2-3 good cycles out of the breaks before you're screwed.

Firstly, you're very wrong. The Leaf has lots of electrically-assisted stuff, but the brakes and steering are anything but complete drive-by-wire: There's still a steering column with a rack and pinion that mechanically turns the wheels. There's still a brake pedal with a master cylinder attached which directly operates the slave cylinders at the wheels.

The only difference between this arrangement on the Leaf and just about everything else is that these components use electric motors for power assistance, whereas traditionally hydraulic pressure or incidental vacuum performed these roles...neither of which make much sense on an electric vehicle.

Secondly, meh. I've been moving dead cars like this for years (I've probably logged over 200 miles of it) -- YOU go try it.

I can quickly stop both my own car (usually a compact, at least by American standards), and the towing vehicle (usually a small pickup truck), with no power-assisted brakes (ie: engine off), and with no braking help from the other vehicle. One must obviously push rather hard on the pedal, but things do stop expediently. Hydraulic automotive brakes are cool like that, and are quite fail-safe indeed.

Same with power steering (or lack thereof): Things work fine without.

(News flash: Did you know that, not so long ago, both of these things were considered optional equipment on a new car?)

And the question is not how long it takes to charge a Leaf to a high state of charge, but rather how long it takes to charge a dead Leaf so that it can travel another 5 miles under its own power, since that is the range discussed in TFA. How long is that?

It takes 21 hours to charge a Leaf from flat to full at 120V, which is supposed to be good for 105 miles of city driving.

Rounding things slightly to make the math simple, and we see that it takes about 20 hours of charging to go 100 miles in-city, or an average rate of about 5 miles-per-hour. So, assuming a constant charge rate (which it isn't -- batteries, in general, tend to accept a charge faster the flatter they are), you'll be be juiced up for another 5 miles of moderate speed travel in about one hour, and certainly less than "SEVERAL HOURS".

It's inconvenient enough to never want to make a habit of doing it, but far from the end of the world or a self-imposed Jeremy Clarkson SNAFU.

If I saw someone stranded in their Leaf outside my house, and all they needed was some electricity, I'd help them push it into the driveway, round up an extension cord, and invite them in for a bit (unless they smelled -really- bad), just as I'd offer a jump to someone with a dead battery, or give whatever gasoline I might have handy to someone who had run their tank dry.

I've fixed disabled cars in parking lots and at the side of the road for total strangers, I've removed the back seat from a car at a gas station after a lady had locked her purse and keys in it, and I've pulled cars out of ditches in the winter. I try to do whatever I can to help just because I can and I usually have the tools with me to do it. The only payment I accept for this sort of unexpected work is "thank you."

I certainly am not the only nice person in the world, though. Others have helped me as well, in one case going so far as to make a steel fitting to repair a radiator hose that had been eaten by the alternator fan, at a factory in the middle of nowhere in the middle of the night. I didn't even have to ask: I just pulled off the road near their loading dock in a cloud of steam, popped the hood, and looked around. Random folks came out, looked with me. I said I didn't need any help. I went to use

Re:Better you say?

[adolf]

Awesome. Thanks!

I've long observed both behaviors, and your description fits nicely with the functional overview that I keep in my head.

(Now I'm even more dangerous.)

Re:Better you say?

[Smidge204]

That's great, but you have no control over it. The heater is basically on all the time the climate control is on no matter what.

Some users have been discussing how to cripple the heater (read: unplug the power/control wires) because they live in Arizona and will basically never ever need it.
=Smidge=

Re:Better you say?

[mattack2]

Is it actually a heater? In an internal combustion car, there isn't actually a heater, you just get 'free' heat from the engine. (Free as in you were paying for the gas to create that heat anyway.)

So there's no warming at all of the batteries or anything else to get 'free' heat from? So it's really essentially a toaster being run by the car to warm you?

Re:Better you say?

[Smidge204]

There's an actual heating element that runs off the traction battery to heat coolant (separate from the motor/inverter/charger coolant) which is circulated through a typical automotive heater core to heat the air blown into the cabin. It's computer controlled to keep the water in the system at some determined temperature based on ambient temp, desired cabin temp, humidity etc.

Even if the motor and electronics generated enough heat (and they may not in some cases) there is no way for the fluid in the two systems to mix.
=Smidge=

Re:Better you say?

[Smidge204]

Why not just screw the included recovery hook into the front bumper? Manuals are often wrong and/or overprotective.

That may well be the case, but I'll let someone else risk voiding the warranty.

The recovery hook is designed for a straight pull - usually onto a flatbed truck - not for towing which may have a lot of lateral forces that could damage the hook and the car. If you want to do it any way, nobody's going to stop you.

The heater is commonly active on any car when the AC is in use. Even one with manual controls: Select appropriate vents, turn AC on, adjust fan speed for a comfortable amount of artificial wind, and then add heat using the temperature knob. Doing it this way helps reduce humidity, and allows for effective bi-level cooling.

On most other cars, the heat is free as a waste product of the engine. On the LEAF, the heat costs drivable battery capacity - up to 5kW. Put into miles driven, that may be as much as 10% of potential driving range. While the reasons you cite for running heat and A/C together are valid, that doesn't mean that it's really optimal in all situations. Why is there no option to control it?

(*The heater is variable output, of course, but that's no excuse for not having an option to disable it)

Meanwhile, the Leaf uses water cooling for some of its electronics. As long as this is the case, using the waste heat to warm up the passenger compartment is free, since the pump was already running anyway for cooling purposes.

False. The fluid in the heating system and the fluid in the motor/inverter/charger cooling system never mix while in operation. There is a common overflow tank, but they each have dedicated degas tanks and circulator pumps. This is another possible design flaw since even with the efficiency of the motor and electronics - if they get hot enough to need active cooling, they get hot enough to assist in cabin heating. Even if they might not get hot enough during a short drive, you have the electric heater element as a backup.

If you don't believe me, drop $20 on the service manual like I did and have a look at the system description and removal instructions.

And setting up a schedule is pretty plainly documented on page CH-18 of the manual, though it looks rather self-explanatory to me: It's all GUI-based.

Here's the full extent of the problem:

If you want to automatically charge to 80% ("long life mode") you must use the timers. There is no way to select 80% charge level if you use the "immediate charge" button. The only way to utilize the "long life mode" function and have immediate charging by default is to configure the timers in an undocumented fashion.

Why couldn't the maximum charge level be set independently of the timers? Why are the only choices 100% or 80%? Some people want to baby the battery but 80% isn't enough, so why not an option for 90% or configurable in increments of 5%? Why not fully configurable so if someone only needs 60% of their battery they can charge to that?

Further, if you have timers set at all, the LEAF will never charge immediately unless the button is pressed. This is a problem for some people since public charger sharing is common practice - so if someone comes and unplugs your car for a bit, and plugs it back in later, it won't continue charging. The car knows when charging is interrupted so you'd think an option to resume interrupted charging would be a no-brainer.

The above also applies if there's a power outage. Charging overnight and you lose power for a few seconds at 1AM? You'll never know it didn't charge until you're leaving for work the next morning.

Is there anything else that you think the smart folks at Nissan got wrong other than the range indicator (which, as I mentioned previously, I don't think is wrong)?

Not

Atleast he knows what hacking is

[Anonymous Coward]

Unlike most people who should have used the term cracking when they say hacking.

Happy hacking - and it's your cars - you are allowed to destroy the batteries.

Re:Atleast he knows what hacking is

[Noughmad]

Happy hacking - and it's your cars - you are allowed to destroy the batteries.

Until the iCar appears.

Re:Atleast he knows what hacking is

[MightyYar]

Then you can just ImpoundBreak it.

Very american?

[Bert64]

To me, hacking is actually very American. Go out to the garage. Take it apart. Make it better.

Sad then that so many american companies are actively trying to restrict or remove people's abilities to do just that, especially on computers where unlike a car anyone can get into it without the need for specialist tools and there is no potential safety risk etc.

Re:Very american?

[rjstanford]

To me, hacking is actually very American. Go out to the garage. Take it apart. Make it better.

Sad then that so many american companies are actively trying to restrict or remove people's abilities to do just that, especially on computers where unlike a car anyone can get into it without the need for specialist tools and there is no potential safety risk etc.

The reason this happens is that there's a large tendency on the part of many people to want to have their cake and eat it too. Your average "hacker" these days is someone who randomly follows vague directions given to them by strangers and, if they screw something up by not understanding what they're doing, expects the original manufacturer of their device to have it replaced at their expense.

This holds true whether you're talking about inompatible software "bricking" a phone, or engine modifications shredding a transmission.

Better hack would be a better battery

[Anonymous Coward]

Goes without saying that this battery tech is designed to fail and require short-term replacement. There are better batteries available and they are tied up in classified patents. Google it, and discover that the current patent systems give fist priority to National Security. National Security is also defined by Economic security.

Re:Better hack would be a better battery

[n2rjt]

I wouldn't say designed to fail, but it does seem that the Leaf is not designed for its batteries to be replaceable.
Given the cost constraints, the engineers picked their battles.
If the electric car catches on and attracts sufficient competition, the free enterprise system will give us better batteries.

Re:Better hack would be a better battery

[PPH]

they are tied up in classified patents.

There isn't any such thing. By definition, patenting something places its description into the public domain (not the right to use, of course). Classified technology isn't published, through patents or other means.

National Security is also defined by Economic security.

And economic security would tend to drive placing better battery technology into the hands of the public so we won't have to buy oil from those nasty Arabs or Canadians. Not keeping it hidden.

Re:Better hack would be a better battery

[PPH]

"The Commissioner then issues a Secrecy Order and withholds the publication of the application or the grant of a patent for such period as the national interest requires."

Semantics: That's not a secret patent. That's not getting a patent.

And its sort of pointless. Anyone with a worthy idea is going to apply for foreign patents as well as US. Particularly with the first to file system prevalent in the rest of the world. If the USPTO sits on a patent for any length of time, the secret is already out in the form of foreign applications.

Yes, the powers that be have a self interest in sealing up certain technologies. Not just oil related stuff, but anything that could conceivably fall under ITAR restrictions. So anyone with the slightest interest in developing their IP commercially gets a copy of their work offshore as fast as possible to beat the national security bullshit. The result is that domestic production is strangled and eventually we'll just buy the batteries from China. Who will respond to US national security concerns with a healthy Bronx Cheer.

Re:All for it, if...

[lennier1]

Pretty much. That limit is there for the same reason your gas tank still has a small emergency reserve left once the indicator reaches zero.

Empty Never Means Empty

[Entropy98]

Gas powered cars still go many miles after the gas gauge hits empty. A fuel gauge reading empty is suppose to tell you "Fill up as soon as possible" not tell you need to get out and push.

Re:Empty Never Means Empty

[vlm]

Gas powered cars still go many miles after the gas gauge hits empty. A fuel gauge reading empty is suppose to tell you "Fill up as soon as possible" not tell you need to get out and push.

Empty means buy a new fuel pump because the old one just sucked up all the water, rust, sand, whatever from the bottom of the tank. Also the in-tank pumps are notorious for overheating and burning out in air/vapor and only running cool when immersed in fuel, so even a perfectly clean tank can burn out the pump if the pump is in an empty tank. Maybe more so in summer than winter... Also if the pump fails after pumping rusty water for awhile rather than instantly, you'll probably end up replacing the fuel filter, maybe the injectors, who knows.

Re:Empty Never Means Empty

[swalve]

Fuel pumps don't move. They always suck from the bottom of the tank. Overheating is a possibility, but even that is doubtful for a pump that is not already on its way out. I mean, if the motor can get hot enough to overheat, that would mean it is getting hot enough to vaporize the fuel in the tank, and that's not a good thing. Most pump designs I've seen have a small reservoir that the pump is submersed in at all times, and if the fuel level is low enough to empty that reservoir, the car quits running in short order.

Re:Empty Never Means Empty

[BillX]

Can you explain this bit about pumping water when the tank is empty? I understand condensation can cause there to be a small amount of water in the gas tank, but last I checked water is heavier than gasoline (it should generally be the first thing pumped). In fact, pilots of some small aircraft - I have seen this done - draw a small amount of fuel from the bottom of the tank into a syringe to check for water bubbles before takeoff.

Also, "sludge" (rust, other particulates) can be a specific problem of empty tanks for large, very stationary tanks (e.g. home heating oil) where sludge can potentially settle on the bottom, away from the intake and remain there 'safely' for some time unless drawn in by dropping fuel level. I can't imagine the same being the case with a car's constantly moving, sloshing tank though. Not the way I drive, at least ;-)

Re:Empty Never Means Empty

[egranlund]

Fuel pumps don't move. They always suck from the bottom of the tank. Overheating is a possibility, but even that is doubtful for a pump that is not already on its way out.

Fuel tanks don't always pull from the bottom. My 1986 Rabbit Convertible has two fuel pumps, one transfer pump on the top of the tank under the back seat which pulls the gas out of the tank and shoots it to the main fuel pump. If you let the tank run dry (or even low and take some hard turns) you risk running the transfer pump dry and having it overheat and die which then causes the main fuel pump to work harder and eventually die a short while afterwards.

I know. It's happened to me. Twice. I've come to the conclusion that keeping your gas tank half full at all times is better than $300 in new fuel pumps.

Re:Empty Never Means Empty

[Richy_T]

I have heard of the overheating issue and have seen places where it could theoretically physically be an issue. The sucking up water & rust I'm in complete agreement with you. The only possible issue there would be from crap floating on top of the gas.

Re:Empty Never Means Empty

[gawbl]

This seems to be the "conventional wisdom," but I've never encountered anyone that had such a failure. I have several fuel-injected cars, and I've worn out a few fuel pumps, but mine always died of old age. Even if your gas tank really has a bunch of water, rust, and sand sloshing around the bottom, I believe that virtually all fuel pumps have an intake filter (or, at least, a screen) to keep that crud out.

Re:Empty Never Means Empty

[Politburo]

OP surely apologizes for not considering the crappy design of your 25 year-old car when writing their comment.

Fucking pedants.

Re:Empty Never Means Empty

[egranlund]

The design of my 25 year old car I'm sure is not out of the ordinary. I've heard later ford SUVs/mini-vans have the same design.

Yes, better, not different

[dutchwhizzman]

It just shows how much of the last bar you still have. Once you go from one bar to zero, you essentially only know you have "less than one bar" left, but not how much. There is no change to how deep the batteries get discharged, you just know better what risk you are taking if you decide to drive on. The TFA also tells about the software "hack" to the 120V charge cable to make it work with 240V as well. That's not so special, considering the same cable is used with different software in Europe, where 240V is the standard. Also improving it to be better, but not different.

Red Sn0W

[Dark Lord of Ohio]

Now it's time for Nissan Leaf firmware red sn0w release. It will add you 10% more on single charge, extra star trek sounds for your silent vehicle and will let you fry your mother in law on the pasenger seat if she will be talking too much. But say goodbye to this extra 10% of power after making your mother in law a chicken nugget.

Re:Red Sn0W

[newcastlejon]

You may have been being facetious, but I've decided that I won't buy an electric car until I can make it sound like the Jetsons'.

Re:Red Sn0W

[SuricouRaven]

Why not? There have been some proposals that electric cars need regulations requiring a minimum noise level as a public safety measure, to reduce the risk of accidents. If there is a minimum noise level, then customiseable car sounds are an obvious idea.

Re:Red Sn0W

[Pence128]

When electric cars are cheap enough for the average me to afford, I'm going to put big ass engine/transmission sound effects in it and see how long it takes for people to notice I seem to have 20 gears.

Re:Why is it "american"?

[icebraining]

Jules Verne does just that in From the Earth to the Moon: The Yankees, the first mechanicians in the world, are engineers-- just as the Italians are musicians and the Germans metaphysicians-- by right of birth..

Re:Why is it "american"?

[TeknoHog]

I also failed to understand why "American" is the opposite of "evil". There are many things that are both, and many things that are neither. I understand why the DIY culture is associated with Americans, but then again, so is the consumerist sheeple culture.

Extended range

[jamesh]

If he wants to extend the range, he could try installing one of these...

Re:Extended range

[rrossman2]

Or figure out a way to stuff one of these in the car....
  http://gigaom.com/cleantech/hyperions-nuclear-in-a-box-ready-by-2013/

Re:Extended range

[fast turtle]

In researching/discussing the different Hybrids, we've determined that both the Prius and Volt are Parallel hybrids; meaning they can run on battery or ICE. The Honda hybrid though is a Series design; meaning that the ICE must run to get anywheres. If you're looking for mileage, buy the normal Civic and get the same mileage with lower emmisions instead of the added complexity.

If I were in the market I'd stick with the Volt model for now. It just makes more sense to have that ICE tether

This is the direction we're figuring on going depending on whether we can get the Volt. I like the styling a bit better then the Prius and the battery range is well within our daily usage. One thing I caught after Hurricane Katrina was that someone had their Prius equiped with an Inverter Pack (dealer option) that allowed the car to function as a UPS system for his house. Meant they didn't have to evacuate and only needed to refuel after 2 weeks, when things stabilized to the point that he could.

Re:Extended range

[spage]

How is it a "leap of faith" to drive within the range of the vehicle? Range anxiety seems to plague people who don't own an electric car... actual owners not so much. Every morning they get in a car they've cheaply "refueled" overnight, do their usual boring commute and shopping run, and return home. If you sometimes find yourself in the middle of nowhere on an unplanned road trip to Vegas, use a different vehicle. There's probably one nearby, since most households in the USA have multiple cars.

Re:Extended range

[Richy_T]

Maybe the AAA could furnish people with towable generators?

Re:Extended range

[Pence128]

Plans for the transition period (lots of electric cars on the road, but no 5 minute charging yet) is a small, rent-able trailer with a generator and engine on it. The engine can be tuned for high efficiency at a single speed. This lets you use an electric car for your daily commute and still use it for the one day a month or so you need to go farther.

Re:Extended range

[rjstanford]

Or, for that matter, spend $30 once a whenever and rent something appropriate from your favorite car rental agency. That way you can also drive a smaller, more practical vehicle most of the time and rent a high-capacity one for the occasional road-trip, rather than trying to make sure that your grocery-getter can also serve every conceivable towing/carrying need you might have in the future.

He is going to regret this shit.

[crow_t_robot]

Bottoming out batteries is absolutely retarded. Even "deep cycle" batteries are only supposed to be discharged to 20% AT THE VERY LOWEST. And doing so reduces the number of cycles by orders of magnitude. Another thing to point out is that batteries become EXTREMELY non-linear in discharge rate at the bottom of their SoC. I like his comment about hacking but everything else is retarded.

Re:He is going to regret this shit.

[OnionFighter]

Deep cycle batteries are a type of lead-acid battery. The Leaf uses lithium-ion batteries, which behave very differently. Still, lithium-ion batteries should never be fully discharged, which may be a risk with his modifications.

Any program that measures charge is making a educated guess based on the past behavior of the battery. One of the people interviewed for the article states: “Until you can find out how much is really left in the batteries toward the end of its range, it’s just a guess-o-meter.” Any indicator of charge is making a guess. Perhaps his program is better at guessing, or maybe he just leaves less room for battery health, but any program that works to tell lithium-ion battery charge will have to take into account the discharge profile of that battery (which is non-linear when measured by voltage).

Re:He is going to regret this shit.

[EsbenMoseHansen]

Bottoming out batteries is absolutely retarded. Even "deep cycle" batteries are only supposed to be discharged to 20% AT THE VERY LOWEST. And doing so reduces the number of cycles by orders of magnitude. Another thing to point out is that batteries become EXTREMELY non-linear in discharge rate at the bottom of their SoC. I like his comment about hacking but everything else is retarded.

If 20% is the "very lowest", then the scale should be recalibrated so that 20% is the new 0%.... :)

Re:He is going to regret this shit.

[sjames]

He's not changing the low voltage cut-off, just the readout on the battery meter.

Re:Why is it "american"?

[vlm]

I'm a bit tired of people claiming that an activity is very american just because the person is from USA and likes it.

You must be the life of the party when an american brings up the topic of "american football" (as opposed to real football = soccer). I'm from the US, our style of football is somewhat popular here (only around 5% really care, but at least 50% go along to get along with them). So our style of football is very american, oh well.

The reason for "american DIY culture" is our profoundly anti-business anti-entrepreneur climate. If you own a set of wrenches in Ecuador even if you mostly work on your own vehicles you'll be considered a "pro car mechanic" by an American if you ever help your neighbor change their windshield wiper blades, so an Equadorian (?) in that situation can't be DIY if they're a businessman, so there is no DIY culture in Equador, even if the same percentage of guys are turning wrenches under a shade tree in their backyard... In the US we have a huge quantity of laws and regulations to prevent individual entrepreneurs from competing with the bigger businesses, because those bigger businesses have purchase the govt and "suggested" those laws to the purchased politicians to improve their profits. I can't even begin to imagine the paperwork and financial resources required to let me change my neighbor's oil for a couple bucks... but I can change my own (so far) without too much govt interference, although they're working on it...

An american DIYer is pretty much just a frustrated entrepreneur. In a better country they're be a very small part time businessman, a dude with a "side job".

Re:Why is it "american"?

[findoutmoretoday]

<quote>the first mechanicians in the world</quote>

That's 100+ year ago,  now it's the Chinese ... again

Home Battery

[Nishi-no-wan]

There were articles earlier in the year saying that the Leaf could be used to power the home in case of emergency, or to give back to the home that is powered by the sun by day and Leaf at night. I asked a guy at the local Nissan dealer when I took my La Festa in for a checkup if I could just have the battery system without the car. He looked at me strange and asked why? I told him that I was looking into alternate energy systems (wind and solar), but none of the solar packages being sold store the power; they all redirect it to the grid. I've researched storage systems, but everything I've found were a mess of old car batteries arranged in serial and parallel. If the Leaf has a single package that can easily connect to the home to charge and discharge, it would be a great help here in Japan since Fukushima went down. (This was still several months ago when energy restrictions were still in effect.) I don't think the guys at Nissan know what a great little package they have there for other uses than to power a car.

Re:Home Battery

[Mspangler]

"If the Leaf has a single package that can easily connect to the home to charge and discharge, it would be a great help"

It's a good notion, but you would be paying a premium for a highly compact and portable power supply that you don't actually need to be highly compact or portable.

And don't use car batteries either, they don't like deep discharge. Use deep cycle batteries like from electric forklifts or golf carts. At the moment, lead-acid batteries are still the cheapest option.

Re:Home Battery

[unkiereamus]

I actually have such a system installed in my home, it's basically just a 3600w charger/inverter hooked up to a bank of 12 12v 110Ah lead gel cell batteries in a series/parallel configuration (The inverter is more efficient working with 24v on the battery side). These aren't old car batteries, as you say, but rather purpose built for this kind of work. The whole thing installs just fine into a closet (Which happens to be the closet where my breaker panel is located.)

Now, I don't do solar or anything like that, I have it because I live in a third-world country, and my power goes out on a semi-regular basis, so this is in effect just a whole-house UPS.

Ultimately, this is no different than the battery backup systems used by server farms etc (aside from scale), and it really is sort of the industry standard set up, because it works.

Re:Why?

[couchslug]

"GEET Heat Exchanger or HHO Water Electrolysis "

Third party public dyno testing per EPA standards or go shoot yourself. The only cure for mental illness is suicide, so hurry up and quit wasting oxygen.

Cranks who probably never (competently) spun a wrench in their lives babbling about tech-cult scams piss me off. Build one that works and get rich, or shut your paranoid clueless piehole. Or go post on Free Republic instead. :)

If you are seriously worried about getting EMPed/HERFed you are too stupid to be an effective rebel against ZOG. Unless you run breaker points or a magneto or a mechanical injection diesel, you are fucked in a running chase if electronic countermeasures are used.

You are fucked anyway since shooting the "nut holding the steering wheel" is the classic old-school solution to crazed trailer trash on the run. See ya on TV!

Re:All for it, if...

[whoop]

Hmm, one would think that someone smart enough to know how to tinker with the car's software would be cognizant enough to know to not let it get down to absolutely zero.

This isn't a mod every person with one of these cars will be doing on their own. It's a hacker's mod. If you know enough to do it, you know what this new zero value will mean.

Re:I see the reason behind it.

[dr2chase]

And if the nearest station is 20 miles away, it's not bad to know whether you have 19 miles of charge left, or 21. There might be a better place to leave your car stopped than 100 yards short of the exit for the charging station.

Re:Why is it "american"?

[jmac_the_man]

You must be the life of the party when an american brings up the topic of "american football" (as opposed to real football = soccer). I'm from the US, our style of football is somewhat popular here (only around 5% really care, but at least 50% go along to get along with them). So our style of football is very american, oh well.

I'm not sure where you're getting your numbers from, but Gridiron Football is far and away the most popular sport in the United States. Gridiron football has been the most popular sport on American television since 1965, and at the moment, it's the only sport that can support two leagues (NFL and NCAA) that are major enough to have regular television contracts.

As far as real football being "soccer," most games called "football" are derived from rugby. "Foot" in their name refers to the fact that the ball was historically 12 inches long from tip to tip. Association Football/Soccer is the sole exception. It was derived from other middle ages games played by peasants. These games were played "on foot" as opposed to games played by nobles (like polo) which were played "on a horse." ("Soccer" was apparently something called "Oxford slang" for "association") Wikipedia has a whole article on the word "Football."

I can't even begin to imagine the paperwork and financial resources required to let me change my neighbor's oil for a couple bucks... but I can change my own (so far) without too much govt interference, although they're working on it...

I'm a conservative. I think one of the major problems with the economy today is TOO MUCH government regulation. That said, most/all jurisdictions allow "personal sales" between neighbors, which allow things like changing your neighbor's oil or having your kid mow their lawn or babysitting or whatever. Have you actually looked into this?

Lithium batteries, depth of (dis)charge

[dr2chase]

This suggests that there's a lot to be said for not driving your battery charge down to "zero" (as defined by the battery controllers and the 3V limit). You'll get many more cycles if you avoid the extremes (full charge, full discharge).

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Re:Why is it "american"?

[Maximum Prophet]

most/all jurisdictions allow "personal sales" between neighbors, which allow things like changing your neighbor's oil or having your kid mow their lawn or babysitting or whatever. Have you actually looked into this?

If you're not a lawyer, stay away from DIY law. There's no way an individual (non-lawyer) in the US can possibly know enough local, state and federal law to safely do this. They've stopped little girls from having lemonade stands for $DEITY's sake.

Re:Why is it "american"?

[vlm]

That said, most/all jurisdictions allow "personal sales" between neighbors, which allow things like changing your neighbor's oil or having your kid mow their lawn or babysitting or whatever. Have you actually looked into this?

The relevant language in this state is "occasional sales" and it requires a business license/registration, less than 20 days/yr of operation, no other licensing requirements (for example, all car air conditioning work requires a license, therefore all car AC work is sales taxable regardless of other conditions), well under poverty line annual income for the exempted work, can not be promoted as a regular ongoing business but solely as an individual transaction, and can not be the primary occupation / source of income for the business. Basically a lot of legal dancing around so church sponsored yard sales are tax exempt without actually writing "church sponsored yard sales are exempt".

So, at least for sales tax, I would not be exempt because I do not have a business license in a non-related profitable line of work. If I owned a scrapbooking store, and then I mowed the neighbors lawn, then it would technically be legally exempt IF I document it, etc.

Note this in no way removes my obligation to pay income tax. (We have a modest rate for both where I live)

Furthermore if I change oil I have all kinds of crazy federal EPA and state requirements. Not crazy if I deal in thousands of gallons per week of toxic used oil, crazy if I do this "once" for a friend in addition to maintaining my own car.

Also its illegal to operate a business of any sort on "my" property without a zoning variance. I'm generously allowed 8 rummage/garage sales per year, but no other exemptions. Technically I am zoned to work on my neighbors car in their driveway as a service to them, think of those mobile windshield repair vans or any building contractor, but I could not work on their car in my driveway.

I paid a lot of extra money to get a non-HOA house, so at least I don't have those little hitlers breathing down my neck, and I have nicer neighbors.

Re:All for it, if...

[Xenx]

The problem is that the new zero value is still an estimate. Maybe the battery dies when it says 3 miles remaining. While I agree that a person should be smart enough to know it cannot be trusted, people put too much faith in those numbers. "I think I can make it to . The computer says I have X miles remaining." I admit I've done it a handful of times with the on-board computer for my old gas guzzler. Then, there is also the fact that 5mi up-hill != 5mi down-hill.

Re:Why is it "american"?

[swalve]

No, they aren't engineers. Just coolies. Again.

Batteries vs. cells

[mbay]

We need to differentiate between batteries and cells. A battery is a group of cells. It is never a good idea to discharge any battery to zero because you will pull some of the cells below zero which means those cells are reversed charged. In NiCads this causes crystal growth that shorts out the reversed cells.

If this 'hack' actually reads individual cell voltages, it would be a great addition. If not, it will probably lead to shortened battery life. Anyone think Nissan will warranty a battery when their BMS system has been bypassed? After all the purpose of the BMS (battery management system) is to protect the battery by keeping the cells in balance, monitoring cell temperatures, and avoiding under and over charge.

Re:Batteries vs. cells

[errandum]

http://www.apple.com/batteries/notebooks.html

Damn, they want to ruin those batteries that are replaced for free if they go under 80% during the warranty period.

Re:Why is it "american"?

[MightyYar]

Well, they didn't say "exclusively American". We have a very strong DIY car culture in this country, if only because we have so many cars per capita and so many people. "Hacking" cars is a very American trait IMHO.

Re:Why is it "american"?

[swalve]

Bullshit. Plenty of people in the US have side jobs, and the regulations are pretty much nil for those. Just pay your taxes and don't rip people off. Some regulations kick in once you start hiring people, but those too are pretty much common sense. Pay them fairly, don't put them in danger. The "onerous" regulations that are the darling of the Know Nothings these days don't kick in once someone has certain numbers of employees, and even then, they aren't really all that bad. I mean, what's the big mean ol' government doing that is so bad?

Re:PR.

[swalve]

I agree. Hacking comes from "hack" which means "someone who isn't very good at the skill" or "to chop at indiscriminately". When one hacks at something, it never means they are doing so in an expert manner. Even in the more modern computer realm, a hack is something that gets the job done, but not in a pretty or efficient manner. A hacker is someone who hacks away at a computer until they get some result.

Re:Why?

[RobbieThe1st]

"Unless you run breaker points or a magneto or a mechanical injection diesel"
Heh. I do. Not for the above reason of course, but... Unless someone manages to hit me with a powerful enough EMP that it literally fries the fuel solenoid coil, I'm pretty sure my truck will continue to operate.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Extra capacity is on purpose

[n2rjt]

Originally, the Leaf's battery meter was more accurate. Zero really meant zero.
One of the first problems reported by new Leaf owners was that they would run out of power while on the road, because they were expecting the meter to work like a typical gas meter, where zero means "fumes", with a few miles to spare.
There was a firmware upgrade, I believe in May 2011, that changed the meter so that zero means about 10 miles. Also Nissan recommends that you only charge to 80% capacity, for increased battery life.

I have never let my Leaf get as empty as zero bars, although sometimes it gets as low as one bar.
A more precise meter would be nice. I'd like to see a one-percent resolution. But I'm happy with it lying a bit about the capacity, because I don't want to be stranded, and I don't want to discharge too deeply. Since I drive over 60 highway miles daily, I do give it 100% charge, which isn't the best. When I get a charger at work (perhaps one of the converted cables mentioned in the article) I'll be able to drop the charge to 80% and extend the battery life.

Re:Extra capacity is on purpose

[Animats]

Right. Auto fuel gauges have had some margin in them for decades.

Aviation fuel gauges, incidentally, do not. Zero is zero.

Re:Extra capacity is on purpose

[Richy_T]

Do you also set your clock five minutes ahead to get to appointments on time?

I really don't understand why some people need to be lied to to operate properly. And it's absolutely infuriating when I stumble over the results of it too.

Re:Extra capacity is on purpose

[sjames]

In a perfect world the firmware would default to the current behavior for the average user and have a way to set zero equals zero if you are willing to look for it. Presumably the people who RTFM enough to change the setting will also be willing to understand that 10% means you really shouldn't drive it any more without charging.

Failing that, next best is a way to update the firmware to implement zero means zero. That's where things are now. Presumably you have to RTFM even more carefully to do the update.

Re:PR.

[spire3661]

A hack CAN be pretty and efficient, but is not required to be.

But it is hacking

[HalAtWork]

Hacking is only portrayed as evil because a lot of reporters don't know what it means, they just base their ideas on crackers, phreakers, and black hats. This is truly a hack in every sense. Own it and give the word back its original meaning. Hacking is not a negative or positive thing, it's a term for an act that may lead to negative, positive, or neutral results.

Re:Why is it "american"?

[Nehmo]

The guy claiming taking something apart is American is referring to innovation and improvisation. These activities depart from the established order, and once upon a time they were rightly called American. But that's not so now. Now, being American is being a conformist in a state controlled order. I'm not even going to discuss the freedom question.
But, for what it once was, you should still capitalize "American".

Re:I see the reason behind it.

[RobertLTux]

cutting things that close will be safe when and only when Gas Stations have some sort of "one gallon gas tank" that can be used on an EV (maybe a 500watt/hour powerpack??)

Re:All for it, if...

[cynyr]

This is my issue with the leaf (apart from living in an apartment with no way to recharge it), The range is what, 40 miles? okay, is that 40 miles, at 45MPH with no accessories? or is that at 30-60 MPH slow-go rush traffic with the heat on when it is -25F out? MY work commute is 32 Miles round trip and is a mix of 55-60 MPH slow-go rush and 35 MPH side roads with minimal stopping. It also routinely gets to be -10F in the mornings and evenings here and we usually have a continuous week or two per winter where the temp doesn't reach above 0F. It also gets to 104F with a 84F dew point in the summers around here(granted record high dew point but still, Jacksonville FL gets to similar). So yes, if i want to pop off to the store(about a 2 mile add to my route home) I would really like to know if i have 6 miles, or 3 miles left. I tend to take the same routes all the time, so i'd know that if it says 30 miles, here one mile down it will say 26, and i can adjust it's mileage number accordingly.

Hacking/hacker/hack

[jim_deane]

Phil Sadow, who was interviewed for the story: 'I don't like the term hacking because it's been portrayed by the media as something evil. To me, hacking is actually very American. Go out to the garage. Take it apart. Make it better.'"

I, on the other hand, love the term "hacking". News media have put a negative spin on the word, but I think we should take it back rather than let them have it. A hacker is nothing more than someone who gets into the guts of things to see how they work and to do cool things with them. Consequently, you can hack anything--computer hardware, software, engines, motors, locks, sewing, knitting, art, math...

Don't let negative reporting take away our words.

Re:Hacking/hacker/hack

[Ingineerix]

When the NYT Reporter interviewed me, I wanted to make it clear that Hacking is a positive activity and try to put a good spin on the term for the public. We definitely need to "Take it back". Sadly, in all the editing this message was lost. -Phil

In other news

[KalvinB]

I have hacked my car so that it no longer tells me I'm out of gas until it actually is.

Re:Why is it "american"?

[HornWumpus]

Tits on men are not good but very American and a tradition among geeks.

Re:I see the reason behind it.

[HornWumpus]

Total range is 40 miles, so you are calling a tow truck, learning to better plan your trips and thinking of buying a real car.

Re:PR.

[HornWumpus]

If it's pretty AND efficient then it's not a hack.

If it's very very ugly then it's a hack. Efficient doesn't enter into the discussion. Hacks can barely work or work great, it's the ugliness of the solution that makes the hack. Some hacks are works of great skill, but they still make the hacker cringe, just a little.

Only the efficient hacks of great skill live for long. I left a hack of a database loader called 'The Firehose' by those assigned to replace it, that I'm still a little ashamed of (I stuffed a weeks worth of hourly data into a single record and split out the hourly data with a query, thus depriving Jet of 167/168 opportunities to suck).

Re:Why?

[couchslug]

OT but handy:

One trucker trick you may already be aware of is to toggle switch the noid so you can pass visual smoke checks.

How the LEAF BMS (Battery Management System) Works

[Ingineerix]

When the LEAF's Lithium-Ion BMS reports 0% SOC, it's not actually at zero charge. The BMS prevents excessive undercharge and also limits the top end, while keeping all cells in balance. It's highly sophisticated and carefully prevents you from doing anything that could damage the pack. They expect the pack to last the life of the car, and they have so much riding on this, you can bet they were very conservative. It's very similar to how Toyota treats the Nickel-Metal Hydride pack in the Prius, wherein they actually only use about half the battery's true capability, and in doing so, they have managed to make the batteries last longer than the car. It's extremely rare to see a battery failure in a Gen-2 (NHW20) Prius for this reason.

Re:Why?

[RobbieThe1st]

Interesting; would you mind explaining more please?
I'm not sure how this would work - disconnecting the solonoid in my case just kills the engine in a second or so due to lack of fuel... do you mean repeatedly flipping it off and on to reduce fuel input?

Re:All for it, if...

[Grishnakh]

You can run a gas engine at full throttle to the last drop of gas. The gas gauge shows empty when there's still gas in the tank because measuring the amount of liquid in an irregularly shaped tank is quite difficult.

Wrong. It shows empty when there's still gas in the tank because otherwise people would be constantly running out of gas. I think Cadillac tried recalibrating their gauges years ago to make empty truly be empty, and had to change back because of all the complaints.

Measuring the amount of liquid in an irregularly shaped tank is quite easy: you just use a simple liquid level sender, and then test its output with various amounts of liquid in the tank. This will let you create a curve to relate the output of the sensor to the actual amount of liquid in the tank. Then, you can program a simple microcontroller to read the sensor level, calculate the actual liquid level given the tank's curve, and output a voltage or other signal to the fuel gauge showing the actual amount of fuel left. It's not hard, at least not with modern electronics, but it would add a few dollars to a car's cost, and most people just don't care that much about fuel gauge accuracy, as long as it still has 3 gallons left when it's "empty". Obviously, this scheme depends on you using the exact same model tank, but for anything mass-produced that's a given. You'd have to modify your uC program any time you change the tank, or if you use a different tank on a different model vehicle, etc.

Re:Why is it "american"?

[Grishnakh]

I'd say a lot of those things, including appreciation of freedom, building a company in your garage, etc., are about as "American" as having a duel in the town square, then going for a drink in the town saloon, etc. They're things that used to be part of American culture in the past, but not any more.

Re:Why is it "american"?

[Grishnakh]

The problem is time. Wearing a six-gun on your hip, and having a shoot-out in the town's main street, are things that used to be part of American culture back in the 1800s, but not any more. Similarly, DIY used to be part of American culture, back in the time when people built giant tech companies out of their garages, but those days are over, and now the consumerist sheeple culture has taken over.

Re:Why is it "american"?

[Grishnakh]

I wonder if he thinks molesting people at airports is a good thing too, as that's something that's completely American.

Re:Why is it "american"?

[adolf]

Where are you from?

In my neck of the woods, it's not alarmingly uncommon for apt folks to have lifts in their home garages to do all manner of work. Sure, it's mostly there because they own or restore nice cars and like to do things themselves, but they'll have their buddy Joe bring his truck over and change the ball joints (or whatever) in exchange for an occasional bit of cash.

I don't know if this is legal (it might be, might not be - we're pretty relaxed with building codes and zoning around here), but I also don't know if your argument is pivoting on the razor-edge of legality or the much broader line that separates practicality from actual legal action.

WRT changing oil: I can imagine that some of the EPA forms are onerous, and that's a shame. You should only have to certify (by your own signature) that you collected n gallons of oil and either burned it yourself in a proper used-oil furnace, or that you delivered n gallons to someone who has such a furnace.

A friend of mine has a completely legitimate used-oil furnace in his small warehouse. I bring my meager used collections over to him, and he's thankful enough to let me use his heated space for the occasional winter car repair. (And if I had a lot of used oil, he'd come and collect it from me himself, and produce a receipt for the same.)

Re:How the LEAF BMS (Battery Management System) Wo

[Spoke]

Mod parent up - he's Phil Sadow who was interviewed in the article and actually knows what he's talking about - unlike 98% of the commenters here who seem to think they know more about how the Nissan LEAF pack is used without actually having done any research.

Re:All for it, if...

[Pence128]

It gets 109 miles in Europe, and 73 in the US due to different driving patterns. Electric cars actually do better in stop and go city traffic than on the highway because they can take advantage of regenerative breaking. Heating however, absolutely tanks your mileage. Maybe knock off 20 with the heat cranked up.

Re:Why is it "american"?

[Pence128]

"Foot" in their name refers to the fact that the ball was historically 12 inches long from tip to tip.

+1 Informative. I always thought it was silly to call it football when you kick it once and then spend the rest of the time carrying it.

Re:I see the reason behind it.

[Pence128]

73 miles by EPA standards, 109 by NEDC (European)

Re:All for it, if...

[Cramer]

That's only true on paper. You have to be *taught* to drive efficiently in an electric/hybrid vehicle. Long slow breaking and gentle acceleration are a must. But you will still lose energy in the process. A moderate, steady speed is the most efficient mode, pretty much for any car, but much more so for electric/hybrid cars as they have somewhere to put excess energy.

Driving my Lexus HS250h, I've found 40+mpg is easy on the highway crusing at 65mph. (70+ starts to pull the mpg's down. 70 is 37-38mpg, 80 is 35-36.) Stop and go city traffic kills it. City only driving falls down to around 35mpg. (38 is doable, but it pisses everybody off -- including me. I can only drive like that when there is *no* traffic around.)

Re:Why?

[Cramer]

I don't have a link, but I recall a trucking fleet adding electrolysis systems to their semi's to feed hydrogen into the engine. They reported a 10% increase in fuel efficiency. At first I thought there's no way that can be true, but when you think about it, that's the same a battery and regen breaks in a hybrid... they're storing excess energy (from the engine, breaking, and gravity) as hydrogen.

Re:genset trailers are DIY only

[Pence128]

Looks like the AC Propulsion model was a complete success right up until the Rav4EV was discontinued. That pusher sounds downright dangerous.

Re:All for it, if...

[Pence128]

Yeah, I said that wrong. What I meant to say is that electric cars do better in cities compared to highway driving compared to gas cars. Gentle acceleration isn't important, as long as you're not flooring it. Long breaking does help a lot, but this is more of a psychological problem. If you wait until the last minute to break, you've just reached the red light faster and spend more time waiting.

There are lots of people who do 65 on the highway maybe once a month, but fight gridlock almost daily. I admit electric cars aren't the silver bullet, but they make sense for some.

Re:All for it, if...

[Cramer]

Long breaking is essential to getting energy back. Aggressive/hard breaking uses the break pads, which just creates heat; you get none of that back.

Re:All for it, if...

[Pence128]

It depends on the charging system. With the right electronics you can regeneratively brake as fast as you can accelerate.

Re:All for it, if...

[Cramer]

True, but the only cars where you'll find such a system is a Tesla or a track/race car. The Prius and it's kind cannot generate that much power from it's electric motor. (and doesn't even try. you can get about 50% braking power from it, but the pads are engaged at that point.

(Unless one uses engine braking, and most people don't know it's there -- the CVT version of "down shifting". But some power is lost from the engine still being engaged.)