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About fast charging, I've seen that Tesla use Panasonic NCR18650B batteries, looking at the datasheet ( http://www.batteryspace.com/pr... ), I see a maximum charging current of 0.5C and it takes nearly 2 hours to get to 80%. I'm genuinely curious as how they manage to get so far out of specs and still maintain decent longevity. Please enlighten me because seriously, every single technical writing I've seen related to Li-ion batteries don't match real-life results, especially regarding fast charge.

I vape since November 7th, 2011. Never smoked a regular cigarette since then.
My current mod is an eLeaf iStick 100W (http://www.eleafworld.com/istick-100w/) holding two 18650 Panasonic batteries (NCR18650B: http://www.batteryspace.com/pr...). The atomizer is an Aspire Nautilus with 1.6 Ohm resistor. I use VW mode on the mod with 14W setting.
Charging the batteries is not done using the integrated mod's charger. I have a certified 18650 battery charger for two batteries, with 1A total charging capacity, that is 500mAh charging capacity per battery. This means the batteries charge slowly. The charger has high temperature and short circuit protection embedded.

My alternate/backup mod is a Cloupor Mini with one battery (same brand/series as above), using an Aspire Nautilus Mini atomizer. The battery does not stay in the mod unless I actively use the mod.

Using products manufactured in China is not a problem. The problem is whether those products are manufactured with strict Quality Control or not. The rule of thumb is: if it's cheap and you never heard of it, don't buy it. And never, EVER skimp on batteries or chargers.

Wish granted.

Awesome now another chip in my phone to help trim away my already bad phone battery life!

Most broad spectrum gas detection sensors generally work by heating up a strange oxide catalyst and measuring a resistance change. Not entirely unlike an O2 sensor in a car exhaust system.

You can buy a gas sensor off the shelf from boutique online stores for about $5 each, so $1 in bulk wholesale is believable, or at least possible.

The problem is power consumption. Check out a MQ-4, at a whopping 750 mW heater power. Thats probably more than the entire rest of the phone at peak. And the heater has to preheat for a minimum of 24 hours to provide good data, this is not something that "goes to sleep mode". Thats 3/4 of a watt, all day, every day. It will literally make a poor hand warmer in ones pocket.

http://www.sparkfun.com/commerce/product_info.php?products_id=9404

http://www.sparkfun.com/datasheets/Sensors/Biometric/MQ-4.pdf

The parts in the sensor are not cheap. The manufacturer is already highly motivated to make it as small and light as possible, which would incidentally make it low powered. At this time, thats the best "we" can do with current technology. Its not like I cherry picked the highest power unit available. However, higher power would imply bigger would imply more durable, so I'd think a cell phone model might actually be worse.

My very-much-non-smartphone uses a 3.7V lithium battery and runs "several days" between charges. Lets claim 4 days. So, 5 volts / 33 ohms = 150 ma times 5/3.7 (voltage upconverter) means 200 ma continuous draw from my 3.7V battery. 200 ma times 24 hours/day times 4 days, equals about 19 AMP-HOURS just to run the gas sensor. We'll add another amp-hour to run the phone itself, and round up to 20 AH.

Batteryspace sells a nice 20 AH lead acid battery... 14 pounds, 7 inches by 3 inches by 7 inches. Rechargeable lithium, maybe half that size and weight. We are looking at the revival of the "bag phone" circa 1980s.

http://www.batteryspace.com/sealedleadacidbattery12v20ah240whs.aspx

I would qualify this idea as an epic fail.

Thus, laptop batteries - while they may be made with the same technology - are as small and dense as possible.

It's true that a few high-end laptops use costly lithium-polymer cells made to specific dimensions. But open a regular laptop battery and 99% of the time you'll find it uses bog standard roughly AA or AAA-size batteries. The charging circuit (~ $3)and plastic case do cost something to produce, but the manufacturers are buying at wholesale prices and cranking these things out by the millions; they should benefit from massive economy of scale.

A battery assembled in China and rebranded by Dell sells for 2x~3x the retail price of the li-ion cells used to make it. The more expensive the laptop, the bigger the ripoff. Grab the same battery direct from China (say, a fairly reputable Chinese company like Agptek) and it will cost about the same, or even slightly less than the retail price of its cells.

Especially brave or foolhardy adventurers could always pry the dead battery case open and solder in some new cells themselves. Apply too much heat, though, and you end up a bomb. Not to mention that the laptop firmware is sometimes designed to prevent the use of refurbished batteries (each battery pack has a unique ID, and the total capacity of the battery pack as reported by the bios can only go down over time, never up - the battery might be 90% full but the OS will see it as 5% and force a shutdown).

Thus, laptop batteries - while they may be made with the same technology - are as small and dense as possible.

It's true that a few high-end laptops use costly lithium-polymer cells made to specific dimensions. But open a regular laptop battery and 99% of the time you'll find it uses bog standard roughly AA or AAA-size batteries. The charging circuit (~ $3)and plastic case do cost something to produce, but the manufacturers are buying at wholesale prices and cranking these things out by the millions; they should benefit from massive economy of scale.

A battery assembled in China and rebranded by Dell sells for 2x~3x the retail price of the li-ion cells used to make it. The more expensive the laptop, the bigger the ripoff. Grab the same battery direct from China (say, a fairly reputable Chinese company like Agptek) and it will cost about the same, or even slightly less than the retail price of its cells.

Especially brave or foolhardy adventurers could always pry the dead battery case open and solder in some new cells themselves. Apply too much heat, though, and you end up a bomb. Not to mention that the laptop firmware is sometimes designed to prevent the use of refurbished batteries (each battery pack has a unique ID, and the total capacity of the battery pack as reported by the bios can only go down over time, never up - the battery might be 90% full but the OS will see it as 5% and force a shutdown).

It's not 1.5V, but...

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1336

O RLY?

It's not 1.5V, but...

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1336

If you're on a business trip for a couple of days without access to a charger then it sure would be nice to have that exteneded talk time. Though it can be considered irrelevant if it uses a standard mini-USB connection as you can always find a shop that'll sell the cable for less than $10.

It uses the same dock connector with other iPods, so it's almost as easy to find a charger... or if you are bringing a laptop, just remember the iPod sync cable.

However there are other external battery solutions like this one.

It may not be a complete solution, but this site sells various pre-made battery packs along with the matching chargers. The only thing you would need to do is attach a connectorized power cable to your GPS' battery contacts.

I did it with my eTrex and I can last all day :)

I'd second many people's comments. NiMH batteries are very very nice these days, and have far more capacity then they used to. http://thomasdistributing.com/ is good, and if you want cheap batteries, http://batteryspace.com/ is good, but their ratings are 400 mAh or so above their actual capacity. Sanyo or PowerEx is certainly good if you have the money, and 2500 mAh Energizers are a good locally available option. The real key is to get a good charger. I just got one of the new Maha MH-C9000 chargers (http://www.thomas-distributing.com/maha-mh-c9000- battery-charger.php) and it has the ability to do break-in charges, discharge, refreshing, etc. You can also just put batteries in it and it will charge them with a safe rate.

For applications like remotes, or other devices you want sitting around for a long time and ready to use, there are new NiMH batteries that have much lower self discharge rates. Eneloop batteries by Sanyo (http://www.eneloop.info/) have performed the best, and they can be picked up locally at Ritz camera locations as well as ordered online for a little less. They only lose a little of their charge over a years time. For more information about rechargable batteries, try the batteries forum over at candlepowerforums. (http://www.candlepowerforums.com/vb/forumdisplay. php?s=04cb1ed93243098d9b7795bae32555cb&f=9)

I'm pretty sure all AAA, AA, C, and D batteries provide roughly the same voltage.

No. Their AAA cell provides 3.7V (that's the Li-Ion cell voltage dictated by physics) and 350 mAh. Compare this to a 1.2V NiMH cell with 850mAh.

Li-Ion cells
NiMH cells

What Li-Ion might improve on is mAh (read: how long they last before needing to be recharged)

Not quite. mAh specifies the charge, not energy; a battery than can supply 100mA for an hour at 100V has much more energy than the one at 3V. With the above two cells, the Li-Ion stores 4.6kJ, which is more than the NiMH with 3.6kJ.

I'm pretty sure all AAA, AA, C, and D batteries provide roughly the same voltage.

No. Their AAA cell provides 3.7V (that's the Li-Ion cell voltage dictated by physics) and 350 mAh. Compare this to a 1.2V NiMH cell with 850mAh.

Li-Ion cells
NiMH cells

What Li-Ion might improve on is mAh (read: how long they last before needing to be recharged)

Not quite. mAh specifies the charge, not energy; a battery than can supply 100mA for an hour at 100V has much more energy than the one at 3V. With the above two cells, the Li-Ion stores 4.6kJ, which is more than the NiMH with 3.6kJ.

I wish I knew where this "hydrogen more practical than batteries" propaganda was coming from, it would make it easier to refute. It's true for lead-acid batteries in long-range applications, probably for NiMH, certainly not for Li-ion especially after the nano-particle electrode advances of Altair and Toshiba.

If you want to see what's out there, check battery suppliers. I look at batteryspace.com every so often. They've got a special on laptop-pack cells right now; if you built a 60 kWh pack out of those, you'd get a tzero-equivalent battery for about $43000, or about 1/10 of what a car-sized hydrogen fuel cell is going for these days. Peak discharge rate on those cells is 2.5C, so you'd get about 150 kW (200 HP) out of them. If you wanted to cut cost and were willing to accept less power, you could cut the size to 15 kWh, max electric power to 37.5 kW (~50 HP) and cost to ~$11,000. At 250 Wh/mile the big pack would let you drive ~240 miles on juice alone, the small one about 60 miles.

It's mighty pricey, but compare to a PEM fuel cell at multiple hundreds of thousands. Even if they come down in price at the same rate, guess what's going to be in showrooms first?

These cells weigh about 43 grams each and hold ~7.2 Wh; the small pack would have about 2100 cells and weigh ~90 kg, the big one 8330 cells and weigh ~360 kg. As I recall, the Ford Focus FCV weighs close to a half-ton more than the conventional version; 800 pounds of batteries is about the same, maybe a bit lighter. Then there's the bulk. 8000 cells at 18 mm diameter and 65 mm long could be stacked in an array to form the floor of the car; arranged widthwise, you'd get 23 cells in 1.5 meters of width, 120 along the 18 mm dimension in 2.2 meters front to back, and a bit less than 54 mm thick stacked 3 tall. That's a bit over 2 inches of vehicle floor, and it doesn't impinge on the trunk or the engine compartment. You're not going to get 10,000 psi tanks into a space that small if your life depended on it.

Neither hydrogen fuel cells nor Li-ion batteries are practical as the sole power source for a vehicle these days. Batteries are a lot closer, and deserve the bulk of the attention.

If they didn't do it, you'd take your money elsewhere.

There's really no "elsewhere" in the laptop market. All manufacturers make dirt upon initial sale but then rape the customer when they break the LCD or need a replacement battery. This is why the laptop industry needs an open laptop form factor - LCD swaps would be about $150 and batteries would be $20.

FWIW, I actually do laptop repair on the side and I've noticed that every battery pack contains the same 3.6V cells. There *is* a standard, the vendors just put the cells into proprietary cases so we can't interchange them.

If you just want 15 miles of all-electric range to get rid of gasoline for all your local trips, the batteries would be $2700. As gasoline heads towards the $2.50/gallon mark and upwards, it would only take a few years for most people's investment in batteries to pay off. Best of all, the price of batteries keeps coming down.

In the article the rechargibles lastes LONGER than the O-rides, by 5 flashes. Recharge these things 3 times and you've more than recouped the cost of recharbles.

Next up is the fact that they were 1800mh batteries. My budget rechargeables are 2300, up from 2250 the year before.

Plus batteryspace.com regularly has a sale, currently you can get 24 rechargables for $29!!!

I see that the Dell one weighs 3.4 lbs, which is about as much as my laptop, and gets "up to 3 hours" run time. I guess that's not too shabby, considering I get about 2 hours now. Combined with the built-in battery, that could make it usable for a cross-country flight, say, where I didn't have a power source.

For a more DIY solution, they also list Li-ion 3.6v cells putting out as much as 2400 mAh. But I have a much older laptop I'd experiment with first. I have lots of things around the house that seem to run off of AA cells, so I might experiment with a bunch of NiMH cells clipped together with things like these first since I've already got quite a few of those cells and chargers lying around.

I thought there was already an iPod external battery pack for sale by someone. A google search shows one for sale by Bilk'n, er, Belkin.

You're right, people have been selling external battery packs for awhile now. But this article seems to be talking about a home-made one called the "Altoids iPod Battery". Why anyone would want to buy this battery pack is beyond me, it looks absolutely horrendous and you can buy a much better looking and capable one from various different vendors.

If you click on "Click Here for Custom Gadgets You Can't Buy" image, it'll open up a window with a picture of this "Altoids iPod Battery".

Here is the caption:

Altoids iPod Battery

This external power source for iPod music players uses three nine-volt batteries to provide up to ten hours of play time.

Ten hours?
This battery claims to provide 40 hours (3G only).
While this one allegedly can provide 14 hours.

All in all it's a really crappy article.

After getting into BattleBots years ago, I decided to reduce my commute to college (before I graduated) by building an electric scooter out of "spare" parts. It's not an e-bike from the standpoint that I didn't want to have to input any energy into the system myself (i.e. the motors had to do all the work). For cost and simplicity reasons, I chose to go with SLA (sealed lead acid) batteries and a couple of overvolted motors. With the proper timing, I achieved a flat speed of 16.5 MPH on two 1HP motors. With 64Ah (@12V) of Pb-acid chemistry onboard (this weighed a whopping 50 pounds), I had a maximum range (tested on all terrain including large hills) of just over 12 miles.

That's what I did and perhaps you can learn from what I would have done differently. First off, I would have used NiMh batteries. This would have cut the weight in more than half and also would have allowed me to customize the pack more both in shape and capacity (I only needed to go 9 miles in a day). The only downside to this was the charge time. SLA batteries are pretty indestructible and I could charge the full 64Ah in around an hour. With NiMh, you're talking about several hours or less if you don't mind compromising lifespan (with the right charger you could charge the same capacity in NiMh in the same time if you didn't mind getting only ~100 charges out of your packs). If I had the cash, I would probably use the high capacity, high discharge Li-Ion batteries from PowerStream (http://www.powerstream.com/LL.htm) as they would be incredibly light (~10 pounds for the same capacity).

As far as the motors went, I was fairly satisfied with the power output, but would have liked more. If you compare it to a car (~100HP for ~2000 pounds), you should have ~10-15HP available for the same performance. Now with electric motors, due to their differing torque curves (in comparison to internal combustion engines), you can achieve similar results from significantly less overall horsepower, but I still would have preferred having 3-6HP on my project.

Of course, if you go with high output motors, you need a speed controller capable of handling the current. And if you go with the Li-Ion batts, you need a fairly expensive charger.

You can take a look at some basic pics of my scooter at:
http://sloviper.com/hobbies/scooter/index.html

A good place for parts is:
http://www.robotmarketplace.com/

Cheap Ni-Mh batteries can be found at:
http://www.batteryspace.com/
I have used them in BattleBots before and they hold up decently, almost as well as the "expensive" ones from http://www.battlepack.com/

If you have any specific questions, feel free to contact me. I love discussing this sort of thing and have had tons of experience. :-)

This one is excellent and well-reviewed in a number of publications: http://www.ccrane.com/quick_charger.asp. I have had mine for a while now and can attest it's excellent. It handles from four AAA through 4 D-cells. It has a slow-start (which prevents the batteries from getting hot), and for NiCd, it even discharges the batteries to 1.0V before recharging them. The spring clip is VERY strong, which helps assure good contact (at least I assume that's why they're so strong). You can leave the batteries in it, too, and it will keep them topped off.

It's not cheap (US$40) but it's been well worth it to me. I use rechargeables for everything and in every size except 9V. I get my batteries from http://www.batteryspace.com/. I like the AA 2250 mAh (currently 24 for US$30); they seem to last forever in my digital camera. My 11-year old daughter goes through batteries like crazy for her CD player, radio, clocks, toys, and flashlights, and going all-rechargeable was one of the best moves I ever made. I do keep a spare set of alkaline D-cells for my radio in case of extended power outage, but haven't had to use them yet (My 8 9500 mAh D-cells, like the A-cells, seem to last forever.

The C. Crane charger says it only does NiCd and NiMH, but I also recharge "rechargeable Alkalines" http://www.rayovac.com/products/recharge/rec_alk.s html in it with no problems.

in the two Palms (IIIxe, IIIx), most of the kids toys, etc. I heard about http://www.batteryspace.com at another forum.

$23.99 for 24 AA 1700mAh
$19.99 for 24 AAA 700mAh
$9.99 for 2 9v 160mAh

they usually are running one promo or another and have some package deals. I don't have the time to test if they live up to the mAh as stated but even if they are off a little it's still about the best $/mAh deal I've found. They do have some higher stated capacities but the price bump to get there wasn't justified in my opinion. Note that I am not affiliated with the aformentiond retailer and I recieve no remuniration for my endorsment.

I don't know if they will love me or hate me for this (no afil)

Battery Space Has some pretty good deals on batteries.

You can get 2000MAH AA's for about a buck a piece, some packages include a charger if you don't have one.

Use this code for 5% off bydusa9981 (no guarantee it works)