Let me compare some of the various cars I've owned:
Car #1: 1981 Toyota Celica - A 2+2 hatchback, 2.4l I4 engine and about 100hp. Curb weight around 2500lbs. Fuel economy in the 22-25mpg range. Car #2: 1996 Toyota Camry - 4 door sedan, 2.2l I4 engine and about 130hp. Curb weight around 3000lbs. Fuel economy in the 25-27mpg range. Car #3: 2003 Subaru Impreza WRX - 4 door wagon, 2.0l I4 turbo charged engine and about 230hp. Curb weight around 3000lbs. Fuel economy in the 25mpg range. Car #4: 2008 Toyota Prius - 4 door hatchback, 1.5l I4 hybrid, about 130hp. Curb weight around 3000lbs, Fuel economy in the 45-50mpg range.
Car #2 has better fuel economy than car #1 even though it weighed 500lbs more. Was a lot more comfortable, and safer, too. Car #3 has nearly double the power than the previous two cars and similar fuel economy. Car #4 is similar power to car #2 but nearly uses nearly half the fuel.
Not to mention that each car also emits far fewer pollutants than the previous vehicle as well.
True, but most of those cheap trickle chargers are also charging NiCd batteries which are much more tolerant of overcharging than NiMH batteries.
Typical NiMH batteries quickly die of overcharged by any significant amount of time and power.
But if you look at all your "cheap" cell phones these days, even they all come with peak detection chargers (pretty much a requirement with Lithium based batteries).
Basic peak detection doesn't cost more than a couple bucks of IC logic (you can get a peak detection charger in a chip, these days). The world would be better off spending a couple bucks on IC logic and extending the life of batteries instead of throwing things away more often.
OK, I did a quick search and yeah, the cheapest chargers are fixed current with a timer to prevent overcharging.
But for a few bucks more you get a charger with basic peak detection.
Back when I was in to RC cars 15+ years ago, my first charger had a basic timer. 15 minutes from a dead pack (standard charge) resulted in a slightly warm NiCd pack. Any longer and it heated up quick.
My limited experience with NiMH SubC packs more recently had them fairly warm after full charge on a peak-detection charger charging at about 1C. Didn't charge any longer than that to see how hot'd they get.
Why anyone would spend $50-$100 on multiple good quality NiMH battery packs and then not spend about the same on a decent peak detection charger defies logic. A good charger maximizes performance of the pack and battery life. Heck, I even went and looked at Tower Hobbies - a basic timer charger costs $25 - a basic peak charger costs $35. I suspect only the uninformed buy the timer chargers these days.
Most of my experience with rechargables these days lie with AA and AAA size cells. I've got a handful of old Eveready NiCd cells (out of a dozen or so) that have been used and abused for about 15 years or so.
Capacity has dropped about 10% from their rated capacity for the ones that still work. The dead ones stopped holding charges for more than a couple days and developed internal shorts (common death scenario for NiCds after being stored dead or forced into reverse voltage when used as part of an imbalanced pack).
The NiMH cells I've used have proven to be much less durable and seem to be much less tolerant of abuse. They have had a much higher rate of capacity loss. I've had probably half my older batch of cells stop holding charges. The other half have lost between 20-30% of their original capacity. Not sure if it's the cheap cells (Powerex, primarily) or NiMH technology (batteryuniversity.com and wikipedia both seem to indicate that NiMH cells are less durable than NiCd cells).
Now I only buy low-discharge NiMH cells. Because your typical cell will basically self-discharge between 20-30% a month, this leaves them useless after only a couple months of storage and dead after 6 months or so. And remember that storing a dead cell also leads to early cell death.
The low-discharge cells will retain about 85% charge after a year and 70% after two years meaning that there is little danger of cells fully discharging and the cells will be ready to use without having to wonder how long ago you recharged the cell. They are also much better for low current applications like clocks and remote controls where battery life won't be determined by how well the cell retains it's charge, but it's actual capacity.
I also use a good digital charger (Powerex MH-C9000) which I can use to monitor the cell's capacity and adjust the charge rate according to the type of cell being charged, as well as easily determine when a cell has reached the end of it's useful life and put it aside for recycling.
They also said that if you detected blacklisted packages on your system, to contact RedHat support by either opening a ticket, calling your local support center or contacting your Technical Account Manager. Did you?
It's not absolutely clear to me whether or not the blacklisted packages have been trojaned or not, but it is clear that all updates obtained through RHN are safe.
What would be interesting to know is how exactly did you get your blacklisted packages installed on your system? Did you get them through RHN or some other channel?
There are a ton of variables that determine battery life, but to say that it relies mostly on your charger is not true when even the most basic charger these days uses peak detection and thermal monitoring to stop charging.
NiMH batteries will _always_ get warm when charging at a decent rate (and most cells like to be charged at a rate somewhere between C/2 and C to get reliable peak detection), because charging them is only 70-80% efficient. The rest goes into heat. If you continue pumping current into them after full, then yes, they heat up quickly.
NiCd batteries only heat up significantly when you continue to charge them after they are full, or you charge them at very high currents.
The #1 killer of typical batteries is letting them sit around dead or pushing them into reverse voltage by draining a pack too far. They like to be stored with at least some charge in them, but too often they end up sitting around for a year or two in between uses and too often they end up sitting dead which kills them. Lithium based cells are so bad that if you drain them completely, you can not revive them, so they typically have a small circuit on them which monitors cell voltage and disables the cell when too low.
There is a ton of information on proper care of batteries including charging here at BatteryUniversity.com including information on what types of behaviour kills certain types of cells the fastest.
Others have already given a good idea of how NiMH batteries are recycled (and how they are relatively benign if not), here is how Tesla is planning on recycling Lithium batteries used in their electric cars when it comes time to replace them:
While NiMH batteries are what's used in just about all hybrid vehicles on the road today, the industry is slowly moving towards as the advantages of Lithium based batteries (higher power to weight ratio, higher power density) outweighs their drawbacks (high cost), and higher energy density is required to make plug-in and pure electric vehicles usable.
Typically, it's not reads that are the performance limitation, but writes, since as you say, you can often throw more memory and/or selective caching to avoid read bottlenecks.
You can only write as fast as your disk can seek, unless you are able to batch small writes into larger ones (typically with the help of a RAID controller with battery backed RAM).
If you say so. I've always heard that they break down very quickly when exposed to sunlight, and I know from personal experience that those plastic bags, even ones that have been sitting in my basement, basically fall apart after only a few years... the old bags aren't worth trying to use, because they're breaking down.
They may be breaking down, but they still leave a huge mess behind and when let loose on the environment, a lot of animals end up eating them, or they end up on the side of the road or on river banks where they take years and years to break down - where a paper bag would decompose very quickly and pose very little to no harm to animals.
In any case, you're also ignoring my other point, which is that plastic bags are currently one of the easiest things to reuse and recycle (other than maybe aluminum cans), and thus by banning them you're basically stopping tons of people from doing any reusing and recycling at all.
The commonly available thin shopping bags are really not all that reusable in my opinion. Typically after only one use they have holes in them, so you're lucky if you can reuse them as trash bags. They're not worth anything so very few people recycle them (unlike aluminum cans which are very valuable). Finding places to recycle plastic bags is also much more difficult than recycling cans or bottles or paper.
Interesting tidbit in this article: According to the Australian Bureau of Statistics, less than 1% of plastic bags used in Australia are reused, however 82.6% of Australian households say that they reuse plastic bags.
Wanting the "save the planet" does not give you the right to tell other people how to live their lives. In fact, I'd go as far as saying that the environmental movement is about the most un-American aspect of the US today.
When one's needless, wasteful and thoughtless actions result in a reduction in the quality of life for others and simple alternatives exist but people refuse to change their behaviour because it may save them a few bucks or just don't give a damn, then yes, that requires regulation. Or do you forget that you share this planet with billions of other people?
Does banning those plastic shopping bags in cities (the new environmentalist trend in hip cities) actually stop any pollution? At all? They're already pretty much bio-degradable, and as somebody who gives not one crap about the environment
No, plastic shopping bags are estimated to take 500-1000 years to decompose under optimal conditions. Some report that they actually never decompose, but end up leaving a plastic "dust" residue.
I can say that those are the *only* things in my entire house that I ever reuse or recycle. (The supposedly-better paper ones I just throw away. In the trash.) I seriously doubt it.
The only reason paper is better than plastic is that it will decompose after a couple months in decent conditions. But paper bags take significantly more energy to produce than plastic and if they end up in a landfill, they take a very long time to decompose because your typical landfill has very poor conditions for decomposition.
The best shopping bags for the environment is to not use any bags at all, but unless you have a lot of hands, that's not really feasible. Reusable canvas bags are very good, but unfortunately most people are either too lazy or think the bags are only for hippies so they don't bother.
While you may view conservation of resources as someone being bossy and telling you shouldn't do something, others view it as their duty to minimize their impact on the Earth so that future generations may also enjoy Earth's resources and beauty.
Trying to get manufacturers to agree on a standard battery would be like trying to get manufacturers to agree on a standard fuel tank. There is simply no way it's going to happen as long as the capability for quick charges exists.
The increase of going from a 1 minute stopover to a 15 minute stopover means that you'll need 15 times the real estate that is in use for current filling stations.
Wait a second - when was the last time you filled up your car in 1 minute? I'd guess that it takes approximately 5 minutes to pump 10 gallons at a typical service station.
But even if it did take 15 times longer, you can put quick charge stations anywhere you have electricity. Put them at each parking spot at the fast-food joint. Put them at rest stops. Put them in the motel parking lot.
The problem with standardized battery packs is that it's not going to be easy or cheap to build a pack which works in most cars, can handle the abuse of being swapped out frequently, etc. Just trying to get a single manufacturer to agree on a standard battery across their own lineup will be difficult, not to mention across multiple manufacturers.
The vast majority of the time, 120 miles is much farther than anyone typically travels in one go.
For those trips exceeding 120 miles, stopping 15 minutes every 2 hours isn't that bad. For example, the longest trip I normally take is about 450 miles which takes about 8 hours and I normally stop 2-3 times. If I have to add another stop to refuel for another 15 minutes so that I can drive a vehicle that is more efficient, that's not a big deal at all.
The only issue is the availability of 15 minute fast charging stations (and the electric vehicles to use them).
I think that once batteries can hold enough energy to go 250 miles at freeway (75mph) speeds and the charging infrastructure is there to recharge in 30 minutes without being prohibitively expensive, there will be little reason to continue driving gas guzzlers.
Even if you have to use a coal power plant to produce the hydrogen, its extremely more efficient than using petroleum in terms of releasing CO2 in the atmosphere.
But when you compare a hydrogen fuel cell vehicle to a pure EV, at best the hydrogen fuel cell vehicle uses 2-3 times more energy for every mile travelled. Not to mention that hydrogen is difficult to source, but you can plug in your vehicle to recharge just about anywhere.
The only benefit a hydrogen fuel cell vehicle has at this stage of the game is that the fuel cell vehicle has better energy density - meaning it can go farther between fill-ups/charges. Current fuel cell vehicles can go 300-500 in between fill ups. Most EVs are limited to about 200 miles or significantly less.
But battery technology is rapidly improving and soon range won't be an issue except for heavy duty trucks.
But the reason for my question isn't even necessarily related (directly) to vehicles, actually: The real point is, so long as we're using fossil fuels, I wonder what the theoretical limits on the efficiency of the getting-work-from-fossil-fuels process are for fuel cells, as different from that for heat engines.
Yep, it's a good question.
Using your example of trying to decide whether to burn natural gas to generate electricity or use it to produce hydrogen or methane for fuel cells, even if we are talking theoretical peak efficiencies, I believe that it's still more efficient to generate electricity.
Using numbers I pull from various sources (primarily wikipedia):
Theoretical efficiency of fuel cell: 83% Theoretical efficiency of gas turbine: 75%
Looking at this, this means that producing hydrogen or methane must be at least 90% efficient to match the efficiency of a gas turbine.
Hydrogen production from natural gas seems to be limited to about 80% efficiency. Hydrogen production from electrolysis seems to be limited to about 50% efficiency.
So yes, even looking at theoretical efficiencies it's more efficient to bypass hydrogen or methane and just use the hydrocarbons to generate electricity where it's practical.
The efficiency of fuel cells is not really that important if you are comparing them to electric cars.
Keep in mind that a fuel cell is a direct replacement of the battery in an pure electric car - fuel cell vehicles are also augmented with batteries. They are basically an electric car with a fuel cell for power storage. So at best it will match the efficiency of an electric car.
Even if the onboard fuel cell was 100% efficient (which they aren't), you still have to figure out how to efficiently produce the energy carrier (Hydrogen). Unfortunately, producing Hydrogen is not very efficient, so at best, you typically end up with over power efficiencies that are very similar to today's hybrid vehicles.
I guess I don't understand how combustion engines are supposedly tapped out.
The problem with ICEs is that you are never going to exceed ~37% efficiency from them. That is the theoretical limit. Most vehicles are about a third to a half that efficient, with diesels and hybrids being better.
Your typical motor is well over 90% efficient.
Commonly used NiMH batteries aren't that great at 60-70% efficiency or so due to heat generated while charging, but newer LiIon chemistries are over 90% efficient as well.
When you combine that with the fact that producing renewable fuels for ICEs are also extremely inefficient compared to sources like wind and solar, it's fairly clear that electrifying the vehicle fleet is best solution on the horizon.
Yes, performance will typically degrade a bit as the batteries lose their charge. The primary reason being that the voltage of the battery will drop as the charge drops. Monitoring the voltage is the primary method of determining a batteries state of charge.
Generally the voltage drop is not significant enough to case any significant performance loss. If this was an issue, you could design in a voltage regulator to maintain output voltage across a wide range of input voltages, but this regulator would incur more resistive losses itself so the overall performance would be worse.
While the batteries used in the Tesla are standard laptop type 18650 cells, they are managed far more effectively that your typical laptop.
There's really nothing special to making making a battery perform reliably, but it does take some work.
I suggest you read Tesla's blog post The Most Coddled Automotive Battery Ever? to learn more about what steps they've taken to extract as much power as they can reliably from the 6,831 individual cells that make up the Tesla's battery pack.
Strange, got another Fedora 9 system (the crashing Firefox in my grandparent post is also a Fedora 9 system) where it doesn't crash when closing gmail with:
Adblock Plus 0.7.5.5 CookieCuller 1.3.1 Firebug 1.1.0b12 Html Validator 0.8.5.1
The real source of road rage is not being able to say, "excuse me." There are two, your high beams and the horn.
Unfortunately, neither really say "excuse me", but instead interpreted as "get the fuck out of my way". At which point the other person generally says "fuck off" and either makes it a point to stay in your way or ignore you.
Never mind that flashing your high beams is the accepted method of indicating to someone else that you would like to pass. I have encountered multiple people who would brake check you or slow down further rather than move over or pull into a pullout to let a faster vehicle pass, no matter how slow they were already going.
So I tap my brakes to get him to back off, he doesn't. While I hate tailgaters just as much as the next guy, I hate people who tap their brakes or even worse brake check people for no apparent reason, other than to send them a signal. (And that's not to say I haven't been guilty of doing the same in the past!)
It's much safer to simply ease off the gas a bit to ensure that you have plenty of space in front of you to account for the lack of space behind you. If you have plenty of space in front, continue at your current rate of speed and move to the right at the next safe opportunity.
The problem with tapping your brakes is that it only further enrages the driver behind you who is very likely already frustrated and already on the verge of road rage if not already. It makes an already unsafe situation worse by further annoying the driver behind you and escalating the situation by encouraging him to look for narrow gaps in traffic to pass.
Again, this is speaking as someone who has been on both sides of the situation.
If you are getting water seeping past the rings when doing water injection, you've got a bigger problem than a bit of water getting in to the sump.
The only time I've heard of water from water injecting getting in to the sump is if your water injector leaks water in to the cylinders when the engine isn't running. And then, the big issue isn't water getting in to the oil, the big issue is hydrolocking your engine will will result in bent rods when you try to start the car.
Under normal operating condition for a water injection setup, the water being injected vaporizes completely because of the heat in the combustion chamber. All the water vapor goes out the exhaust. Even if a tiny bit does manage to get past the rings and in to the sump, it will remain in vapor form as long as the engine is warm, remember, than your typical engine runs with the coolant passages near boiling temps and the rest of the engine (including the oil) is usually above boiling temps.
Slashdot Mirror
Exactly.
Let me compare some of the various cars I've owned:
Car #1: 1981 Toyota Celica - A 2+2 hatchback, 2.4l I4 engine and about 100hp. Curb weight around 2500lbs. Fuel economy in the 22-25mpg range.
Car #2: 1996 Toyota Camry - 4 door sedan, 2.2l I4 engine and about 130hp. Curb weight around 3000lbs. Fuel economy in the 25-27mpg range.
Car #3: 2003 Subaru Impreza WRX - 4 door wagon, 2.0l I4 turbo charged engine and about 230hp. Curb weight around 3000lbs. Fuel economy in the 25mpg range.
Car #4: 2008 Toyota Prius - 4 door hatchback, 1.5l I4 hybrid, about 130hp. Curb weight around 3000lbs, Fuel economy in the 45-50mpg range.
Car #2 has better fuel economy than car #1 even though it weighed 500lbs more. Was a lot more comfortable, and safer, too.
Car #3 has nearly double the power than the previous two cars and similar fuel economy.
Car #4 is similar power to car #2 but nearly uses nearly half the fuel.
Not to mention that each car also emits far fewer pollutants than the previous vehicle as well.
True, but most of those cheap trickle chargers are also charging NiCd batteries which are much more tolerant of overcharging than NiMH batteries.
Typical NiMH batteries quickly die of overcharged by any significant amount of time and power.
But if you look at all your "cheap" cell phones these days, even they all come with peak detection chargers (pretty much a requirement with Lithium based batteries).
Basic peak detection doesn't cost more than a couple bucks of IC logic (you can get a peak detection charger in a chip, these days). The world would be better off spending a couple bucks on IC logic and extending the life of batteries instead of throwing things away more often.
OK, I did a quick search and yeah, the cheapest chargers are fixed current with a timer to prevent overcharging.
But for a few bucks more you get a charger with basic peak detection.
Back when I was in to RC cars 15+ years ago, my first charger had a basic timer. 15 minutes from a dead pack (standard charge) resulted in a slightly warm NiCd pack. Any longer and it heated up quick.
My limited experience with NiMH SubC packs more recently had them fairly warm after full charge on a peak-detection charger charging at about 1C. Didn't charge any longer than that to see how hot'd they get.
Why anyone would spend $50-$100 on multiple good quality NiMH battery packs and then not spend about the same on a decent peak detection charger defies logic. A good charger maximizes performance of the pack and battery life. Heck, I even went and looked at Tower Hobbies - a basic timer charger costs $25 - a basic peak charger costs $35. I suspect only the uninformed buy the timer chargers these days.
Most of my experience with rechargables these days lie with AA and AAA size cells. I've got a handful of old Eveready NiCd cells (out of a dozen or so) that have been used and abused for about 15 years or so.
Capacity has dropped about 10% from their rated capacity for the ones that still work. The dead ones stopped holding charges for more than a couple days and developed internal shorts (common death scenario for NiCds after being stored dead or forced into reverse voltage when used as part of an imbalanced pack).
The NiMH cells I've used have proven to be much less durable and seem to be much less tolerant of abuse. They have had a much higher rate of capacity loss. I've had probably half my older batch of cells stop holding charges. The other half have lost between 20-30% of their original capacity. Not sure if it's the cheap cells (Powerex, primarily) or NiMH technology (batteryuniversity.com and wikipedia both seem to indicate that NiMH cells are less durable than NiCd cells).
Now I only buy low-discharge NiMH cells. Because your typical cell will basically self-discharge between 20-30% a month, this leaves them useless after only a couple months of storage and dead after 6 months or so. And remember that storing a dead cell also leads to early cell death.
The low-discharge cells will retain about 85% charge after a year and 70% after two years meaning that there is little danger of cells fully discharging and the cells will be ready to use without having to wonder how long ago you recharged the cell. They are also much better for low current applications like clocks and remote controls where battery life won't be determined by how well the cell retains it's charge, but it's actual capacity.
I also use a good digital charger (Powerex MH-C9000) which I can use to monitor the cell's capacity and adjust the charge rate according to the type of cell being charged, as well as easily determine when a cell has reached the end of it's useful life and put it aside for recycling.
RedHat specifically said that packages obtained through RHN were safe. Do you get all your packages through RHN?
http://www.redhat.com/security/data/openssh-blacklist.html
They also said that if you detected blacklisted packages on your system, to contact RedHat support by either opening a ticket, calling your local support center or contacting your Technical Account Manager. Did you?
It's not absolutely clear to me whether or not the blacklisted packages have been trojaned or not, but it is clear that all updates obtained through RHN are safe.
What would be interesting to know is how exactly did you get your blacklisted packages installed on your system? Did you get them through RHN or some other channel?
There are a ton of variables that determine battery life, but to say that it relies mostly on your charger is not true when even the most basic charger these days uses peak detection and thermal monitoring to stop charging.
NiMH batteries will _always_ get warm when charging at a decent rate (and most cells like to be charged at a rate somewhere between C/2 and C to get reliable peak detection), because charging them is only 70-80% efficient. The rest goes into heat. If you continue pumping current into them after full, then yes, they heat up quickly.
NiCd batteries only heat up significantly when you continue to charge them after they are full, or you charge them at very high currents.
The #1 killer of typical batteries is letting them sit around dead or pushing them into reverse voltage by draining a pack too far. They like to be stored with at least some charge in them, but too often they end up sitting around for a year or two in between uses and too often they end up sitting dead which kills them. Lithium based cells are so bad that if you drain them completely, you can not revive them, so they typically have a small circuit on them which monitors cell voltage and disables the cell when too low.
There is a ton of information on proper care of batteries including charging here at BatteryUniversity.com including information on what types of behaviour kills certain types of cells the fastest.
Others have already given a good idea of how NiMH batteries are recycled (and how they are relatively benign if not), here is how Tesla is planning on recycling Lithium batteries used in their electric cars when it comes time to replace them:
Mythbusters Part 3: Recycling our Non-Toxic Battery Packs
While NiMH batteries are what's used in just about all hybrid vehicles on the road today, the industry is slowly moving towards as the advantages of Lithium based batteries (higher power to weight ratio, higher power density) outweighs their drawbacks (high cost), and higher energy density is required to make plug-in and pure electric vehicles usable.
Typically, it's not reads that are the performance limitation, but writes, since as you say, you can often throw more memory and/or selective caching to avoid read bottlenecks.
You can only write as fast as your disk can seek, unless you are able to batch small writes into larger ones (typically with the help of a RAID controller with battery backed RAM).
They may be breaking down, but they still leave a huge mess behind and when let loose on the environment, a lot of animals end up eating them, or they end up on the side of the road or on river banks where they take years and years to break down - where a paper bag would decompose very quickly and pose very little to no harm to animals.
The commonly available thin shopping bags are really not all that reusable in my opinion. Typically after only one use they have holes in them, so you're lucky if you can reuse them as trash bags. They're not worth anything so very few people recycle them (unlike aluminum cans which are very valuable). Finding places to recycle plastic bags is also much more difficult than recycling cans or bottles or paper.
Interesting tidbit in this article: According to the Australian Bureau of Statistics, less than 1% of plastic bags used in Australia are reused, however 82.6% of Australian households say that they reuse plastic bags.
When one's needless, wasteful and thoughtless actions result in a reduction in the quality of life for others and simple alternatives exist but people refuse to change their behaviour because it may save them a few bucks or just don't give a damn, then yes, that requires regulation. Or do you forget that you share this planet with billions of other people?
The fact that it's been 50 years and we're still not quite sure how long a plastic bag takes to break down / decompose says something, no?
And you're right - plastic bags don't really "decompose", they break down into smaller bits of plastic, but still plastic.
You also recognize that plastic bags exposed to sunlight break down faster than bags that aren't, thanks to UV rays.
(BTW, did you reply to the wrong post? It seems that your response was directed to the grand-parent post, not mine)
No, plastic shopping bags are estimated to take 500-1000 years to decompose under optimal conditions. Some report that they actually never decompose, but end up leaving a plastic "dust" residue.
The only reason paper is better than plastic is that it will decompose after a couple months in decent conditions. But paper bags take significantly more energy to produce than plastic and if they end up in a landfill, they take a very long time to decompose because your typical landfill has very poor conditions for decomposition.
The best shopping bags for the environment is to not use any bags at all, but unless you have a lot of hands, that's not really feasible. Reusable canvas bags are very good, but unfortunately most people are either too lazy or think the bags are only for hippies so they don't bother.
While you may view conservation of resources as someone being bossy and telling you shouldn't do something, others view it as their duty to minimize their impact on the Earth so that future generations may also enjoy Earth's resources and beauty.
Trying to get manufacturers to agree on a standard battery would be like trying to get manufacturers to agree on a standard fuel tank. There is simply no way it's going to happen as long as the capability for quick charges exists.
Wait a second - when was the last time you filled up your car in 1 minute? I'd guess that it takes approximately 5 minutes to pump 10 gallons at a typical service station.
But even if it did take 15 times longer, you can put quick charge stations anywhere you have electricity. Put them at each parking spot at the fast-food joint. Put them at rest stops. Put them in the motel parking lot.
The problem with standardized battery packs is that it's not going to be easy or cheap to build a pack which works in most cars, can handle the abuse of being swapped out frequently, etc. Just trying to get a single manufacturer to agree on a standard battery across their own lineup will be difficult, not to mention across multiple manufacturers.
The vast majority of the time, 120 miles is much farther than anyone typically travels in one go.
For those trips exceeding 120 miles, stopping 15 minutes every 2 hours isn't that bad. For example, the longest trip I normally take is about 450 miles which takes about 8 hours and I normally stop 2-3 times. If I have to add another stop to refuel for another 15 minutes so that I can drive a vehicle that is more efficient, that's not a big deal at all.
The only issue is the availability of 15 minute fast charging stations (and the electric vehicles to use them).
I think that once batteries can hold enough energy to go 250 miles at freeway (75mph) speeds and the charging infrastructure is there to recharge in 30 minutes without being prohibitively expensive, there will be little reason to continue driving gas guzzlers.
But when you compare a hydrogen fuel cell vehicle to a pure EV, at best the hydrogen fuel cell vehicle uses 2-3 times more energy for every mile travelled. Not to mention that hydrogen is difficult to source, but you can plug in your vehicle to recharge just about anywhere.
The only benefit a hydrogen fuel cell vehicle has at this stage of the game is that the fuel cell vehicle has better energy density - meaning it can go farther between fill-ups/charges. Current fuel cell vehicles can go 300-500 in between fill ups. Most EVs are limited to about 200 miles or significantly less.
But battery technology is rapidly improving and soon range won't be an issue except for heavy duty trucks.
Any idea why that happens? I always thought along the same lines as the grand-parent post.
Yep, it's a good question.
Using your example of trying to decide whether to burn natural gas to generate electricity or use it to produce hydrogen or methane for fuel cells, even if we are talking theoretical peak efficiencies, I believe that it's still more efficient to generate electricity.
Using numbers I pull from various sources (primarily wikipedia):
Theoretical efficiency of fuel cell: 83%
Theoretical efficiency of gas turbine: 75%
Looking at this, this means that producing hydrogen or methane must be at least 90% efficient to match the efficiency of a gas turbine.
Hydrogen production from natural gas seems to be limited to about 80% efficiency.
Hydrogen production from electrolysis seems to be limited to about 50% efficiency.
So yes, even looking at theoretical efficiencies it's more efficient to bypass hydrogen or methane and just use the hydrocarbons to generate electricity where it's practical.
The efficiency of fuel cells is not really that important if you are comparing them to electric cars.
Keep in mind that a fuel cell is a direct replacement of the battery in an pure electric car - fuel cell vehicles are also augmented with batteries. They are basically an electric car with a fuel cell for power storage. So at best it will match the efficiency of an electric car.
Even if the onboard fuel cell was 100% efficient (which they aren't), you still have to figure out how to efficiently produce the energy carrier (Hydrogen). Unfortunately, producing Hydrogen is not very efficient, so at best, you typically end up with over power efficiencies that are very similar to today's hybrid vehicles.
The problem with ICEs is that you are never going to exceed ~37% efficiency from them. That is the theoretical limit. Most vehicles are about a third to a half that efficient, with diesels and hybrids being better.
Your typical motor is well over 90% efficient.
Commonly used NiMH batteries aren't that great at 60-70% efficiency or so due to heat generated while charging, but newer LiIon chemistries are over 90% efficient as well.
When you combine that with the fact that producing renewable fuels for ICEs are also extremely inefficient compared to sources like wind and solar, it's fairly clear that electrifying the vehicle fleet is best solution on the horizon.
Yes, performance will typically degrade a bit as the batteries lose their charge. The primary reason being that the voltage of the battery will drop as the charge drops. Monitoring the voltage is the primary method of determining a batteries state of charge.
Generally the voltage drop is not significant enough to case any significant performance loss. If this was an issue, you could design in a voltage regulator to maintain output voltage across a wide range of input voltages, but this regulator would incur more resistive losses itself so the overall performance would be worse.
While the batteries used in the Tesla are standard laptop type 18650 cells, they are managed far more effectively that your typical laptop.
There's really nothing special to making making a battery perform reliably, but it does take some work.
I suggest you read Tesla's blog post The Most Coddled Automotive Battery Ever? to learn more about what steps they've taken to extract as much power as they can reliably from the 6,831 individual cells that make up the Tesla's battery pack.
Strange, got another Fedora 9 system (the crashing Firefox in my grandparent post is also a Fedora 9 system) where it doesn't crash when closing gmail with:
Adblock Plus 0.7.5.5
CookieCuller 1.3.1
Firebug 1.1.0b12
Html Validator 0.8.5.1
A quick google on "firefox gmail close crash" turns up a ton of hits to go off and read...
Interesting, I notice the same thing happening as well when I close my tabs out at the end of the day. Close Gmail and boom!
I have these extensions installed:
CookieCuller 1.3.1
Firebug 1.1.0b12
Firesizer 0.64
FlashGot 1.0.4.2
Html Validator 0.8.5.1
Nagios Checker 0.12.2
What about you?
Unfortunately, neither really say "excuse me", but instead interpreted as "get the fuck out of my way". At which point the other person generally says "fuck off" and either makes it a point to stay in your way or ignore you.
Never mind that flashing your high beams is the accepted method of indicating to someone else that you would like to pass. I have encountered multiple people who would brake check you or slow down further rather than move over or pull into a pullout to let a faster vehicle pass, no matter how slow they were already going.
It's much safer to simply ease off the gas a bit to ensure that you have plenty of space in front of you to account for the lack of space behind you. If you have plenty of space in front, continue at your current rate of speed and move to the right at the next safe opportunity.
The problem with tapping your brakes is that it only further enrages the driver behind you who is very likely already frustrated and already on the verge of road rage if not already. It makes an already unsafe situation worse by further annoying the driver behind you and escalating the situation by encouraging him to look for narrow gaps in traffic to pass.
Again, this is speaking as someone who has been on both sides of the situation.
If you are getting water seeping past the rings when doing water injection, you've got a bigger problem than a bit of water getting in to the sump.
The only time I've heard of water from water injecting getting in to the sump is if your water injector leaks water in to the cylinders when the engine isn't running. And then, the big issue isn't water getting in to the oil, the big issue is hydrolocking your engine will will result in bent rods when you try to start the car.
Under normal operating condition for a water injection setup, the water being injected vaporizes completely because of the heat in the combustion chamber. All the water vapor goes out the exhaust. Even if a tiny bit does manage to get past the rings and in to the sump, it will remain in vapor form as long as the engine is warm, remember, than your typical engine runs with the coolant passages near boiling temps and the rest of the engine (including the oil) is usually above boiling temps.