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Poor man's lithium
Inspired by MetroMPG and a thread elsewhere, I am beginning to think about using Lithium to power E-Sandra. Here's my logic: a Tesla uses 6,831 of the 18650 laptop batteries to go 200 miles (according to some dude, I haven't bothered to check, and 6,798 according to MetroMPG). So, since I need 2 miles, I can use 68 of them, right?:p
Yes, I'm kidding, but not totally. I mean, I'm certainly not going Tesla speeds and laptop batteries are not crazy expensive: I can get 2 of them NEW (wow, something NEW in my car:D) for $4. So a decent pack shouldn't be TOO crazy expensive. The biggest drawback will be BMS. Tesla has all kinds of safety stuff I won't have. Then there's charging: I can picture me taking my batteries out every night and hooking up 20 or so power supplies. So my "pack" would need to be taken apart every day for charging...... Any comments appreciated..... |
They hypermiled that Tesla for that mileage, so don't expect your numbers to be that good. I do see where you're going with it though. I don't know about charging individually though, that will probably get old FAST!
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I'd sure like to know where you get 2 new lithium laptop battery packs for $4.
My understanding is that the single most expensive component of the Tesla is the lithium battery pack. |
You guys realize that "lithium batteries" are about as specific as a "fuel driven car" right?!
Laptop batteries may be what comprises the building blocks to the battery pack in the Tesla roadster... But what makes it work in a EV with quite different demands than a laptop is the smart little chips surrounding it... Trying to charge a pack of that many cells without BMS is asking for trouble... And charging separately is a PITA... If you really can get them new for $4 you could probably spend the money to get the most basic BMS (or DIY one) and charge them as 12V/24V/48V blocks at least... Then you'd only need a few chargers or PS's to plug in... Still a hassle, but of a different magnitude... |
PbH2SO4 is the poor man's lithium. Either that or junkyard NiMH.
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I think the Tesla uses cells from A123 which are not quite the same as the batteries that you find in your laptop.
The big difference is that the A123 cells can tolerate extreme rates of charge and discharge, far in excess of what a laptop battery can take. The A123 battery does have lithium in it. If you are dying for these cells the new DeWalt 36V batteries have them. If 2miles is your goal might I suggest a good pair of feet? Failing that this is well well within the technical limit of good old lead acid. |
how many watt hours per mile do you need?
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Well rough estimate 15hp gets you 60mph so 2 min would do it.
15hp goes to 12.5kw x .05hrs give about 0.625 kwh. That would be 10 laptop packs (bearing in mind that won't work). |
Most batteries can not handle the kind of electrical draw that is needed to power a car, my 1,400 pound car draws as much as 25,000 watts when starting from a dead stop, 600 amps for a second or more at 48 volts, most if you try to draw that out of a laptop battery, or even 10 laptop batteries they will melt, start on fire, or produce some other thermo event.
Dewalt packs are A123 batteries, they have better specs then lap top batteries but still if I remember correctly 75 amps out of a single 33 volt (labeled as 36 volt) pack can be drawn for a second or more, of course the BMS does not allow that kind of discharge, it's limited at around 15-20 amps, I could see having a few deep cycle lead acid starting batteries and a lithium battery that keeps them charged, so the lead acid would act as a buffer, that could work. |
I still have not made up my mind what to do with my City-EL. Lithium batteries has been tried in the UK about 2 years ago then it was mysteriously sold. Story ended right there- no plusses, no minuses- nothing.
Out of about 60 C-ELs sent to Sacramento in 1992-1993; I have one of about 5 operating. I have seen 4, but only 1 has lithium batteries (as of Oct. I think) instead of the 4 lead-acid deep cell batteries. Not enough "trial and error" for me to know for sure if I should go that route. With a primary, secondary, and that computer circuit charging circuit, deciding which batteries has always been a problem- several times I have charged all 4 batteries one by one (that got VERY old VERY fast!) then I just lost patience and left those computer power sources 'on' along and used an external charger at the same time- takes about 6 hours. I think I will get 4 lead-acid batteries from Costco- even that price is terrible: $280.+ but the ones in it were $1300.+. Lithium batteries are very expensive. |
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Poor man's lithium... has it been done yet? (EV Album - Battery Type: Lithium-Ion ) To do this on the cheap, I have a feeling you'd need an "in" with a company that sells/services lithium powered products ... or even a cell manufacturer. You need access to castoffs/bad modules you can harvest good cells from. Another way to look at this would be to look at lithium is an investment. Treated properly, you can conceivably get multiple thousands of cycles from your cells, so you could have them for years and years. Even move them from vehicle to vehicle. Per mile, they're less expensive than lead acid. New lead acid, that is. Nahh... I'd like to see someone do it on the cheap! |
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On that list is a bunch of confused people, not people using Li-Ion... Zoltan Szirmay's 1991 Fiat Tipo 1.4 ... No Thundersky does NOT make Li-Ion batteries... They use LiFePo4 chemistry... Devinci's Mini-Baja Electric ... Neither does a 123, guess what they are "famous" for? Oh right, LiFePo4 cells... Same goes for most on that list... They reference A123 cells or Thundersky, or a bunch of other manufacturers that use LiFePo4 chem... Show me one example of Li-Ion batteries in a DIY EV that works and I'll shut up, but until then I'm gonna yell and shout... LiFePo4 is radicaly different from both Li-Ion and LiPo people... Nobody on that list is using Li-Ion... They are just confused about what they are using... A LiPo cell is prone to blowing up if charged the wrong way... Building a pack for a car with that would be stupid in an order of magnitude untold... They are very common in small packs made for RC planes and such and are ideal as someone said for the lights on a bike (think it was tadpoletrike?)... But definetly not for a traction pack... Li-Ion is very, very picky about charging voltage... Charge one cell the wrong way and it goes dead... And nothing brings it back... There are most defintly EV's using them... All of them are factory products with advanced BMS systems... Not DIY builds... As i said in my previous post... Saying "Lithium battery" is like saying "fuel"... It can be horsemanure or moonshine or whatever... Get the fact straigth before you start confusing others... Please?! There is a lot of knowledge on this site... And a lot of you are my guides in EV building (planning so far...) But in this you need to do some research... |
the issue is that lithium batteries degrade over time, aka a new laptop battery will only last 3 years from mfg date before it is under 50% capacity. I am not sure if other types last longer but that is what I found out about laptops last year when I rebuilt my own pack. I would be interested to see how long the Telsa's battery pack lasts before it needs replacement.
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Tweety: breathe... Again... Calm, calm. :)
I didn't choose the misleading words Lithium-Ion in my previous post - the forum software grabbed those words from the EV Album itself. So obviously if the EV Album doesn't use the right terminology it's probably fair to say there's a fair amount of ignorance out there about lithium chemistries. (And I'll happily admit I'm at the bottom of the lithium learning curve myself.) By all means, please feel free to clarify & educate! Please do! Your input is welcome - looks like you've done the homework. (But also tune in to the light-hearted nature of the thread - or just about any thread Paul has started! Have you read his Metro conversion saga? :D I'd buy tickets to read an "immersion learning" experience authored by Paul about somehow using lithium to power an EV on the cheap. I have a feeling by the end of it there would be a fair amount of clarity about the idiosyncrasies of the different chemistries.) |
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The Panasonic Oxyride Speed Challenge – The Blogs at HowStuffWorks Then, my ecofriendly conscience took over, and I realized the only way to go is rechargeable. The DIY version that most closely resembles what I'm looking for can be found here: http://www.youtube.com/watch?v=wneCR...eature=channel So, according to the pack I have, that would mean I need to research "nickel cadmium". Also, I was well aware of the fact that laptop batteries as a "fuel" were a good choice originally BECAUSE of the fact that they are so picky about charging and stuff; I've seen those videos where they catch fire, and it seems to me that it could serve a dual purpose: power the car AND provide that oh-so-unobtainable heater system that everyone always talks about. I don't think nickel cadmium goes "boom" though, so that might not be the best choice. Yeah, I need to research. I think for the time being, until I pin down a "fuel" that my rechargeable batteries will use, I'll refer to them as "go-juice containers". |
Heh... I'm calm... I know Paul's threads are a bit special...;)
Um... To clarify... If you wan't heating included in the battery pack, don't use LiFePO4 chemistry... It's the most stable one... It goes "hiiiissss" and lets out the magic smoke... Not that interesting at all...:( LiPO is by far the most interesting one...;) I have so far managed to destroy 3 toy airplanes and one very, very small helicopter when charging LiPO's... And made one kitchen table unusable, or well, the significant other deemed it so based on the burn marks... To me it still looks like a table, but what do I know... :confused: The Li-Ion one's don't catch fire very often... It takes a lot of hard work to make them blow up even half as spectacular as LiPO's... Like hammering nails into them, or hitting them with hammers... If you just abuse them with a charger they mainly tend to wave bye-bye and die quietly... |
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In November 2003 it was dead anyway. Later in 2003 I began building my E-Pod (finished 2005). It has 3 plain old lead-acid batteries (36V). In the last 5 years that City-EL in the UK went lithium (I think Germany sells them new with lithium) with HUGE insulation pads. Tesla had problems with batteries overheating- something like a refrigerator was needed. I am still extremely wary! Photo is a new 2009 City-EL in Berlin. |
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LiPO was a follow up, much more energy content for it's weight and faster charge/discharge, but in terms of reliability I'd probably label it "unstable"... It's in the same category as fireworks as far as I'm concerned...;) LiFePo4 or LFP is kind of the opposite... A bit less energy per weight (the Fe part is iron phosphate, which is heavy) But much more stable... Unless you deep cycle or rapid charge them during their break in period they are pretty hard to kill... I have had cells come back to life from abuse that would have killed of most other battery cells... I have a few cells in one of my packs for an RC heli that have survived a 50' drop... They are still performing as new (and they look far from it!)... That drop was promptly followed up by severely overcharging them, and later deep cycling them a few times, still they refuse to die... Blowing up a LiFePO4 cell is hardly an issue... At most they will make an evil hiss... No bang... And no flames... Very dissapointing to say the least... I had a LiPO pack go supernova from a bad landing and destroy an RC plane... Another one decided to have a hissy fit when it was pinched in the exact worst possible spot and melt an RC heli... Several have selfdestructed during charging... One however decided to be an exception and just quietly refused to hold a charge... Other than that all of them have definetly been windictive when they where "mistreated"... |
I gave up the "lithium" idea, as the 6 month silence implies. But last night, as I was trying to sleep, my mind wandered in this direction again. That, and Jack Rickard's videos every Friday talking about Chinese prizmatics. There HAS to be a cheap way of doing something other than lead/acid for me. Even the beat up left for dead batteries I use seem a bit overkill for the 1.7 miles I require of them. I'd be trimming a bunch of weight too if I could put something else in there. Anyway, I bought ONE battery (with no way to charge it:p):
New Lifepo4 A123 18650 1000-1100mah battery Cell 1Pcs - eBay (item 120581586100 end time Jul-10-10 08:40:03 PDT) (This is pretty much just throwing money out the window because I've never seen an LiPO4 battery with such low mAh rating. Must be factory seconds- or 25ths:p) |
The 18650 is a little bigger than a AAA battery: 18mm diameter, 65mm length. So that's why it's only 1Ah. It might be fun to see how far you can go on a charge on one of those.
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More half way between an AA(A really, but I doubt many folks here have seen a cylindrical A cell before) and C cell tho slightly longer than even the latter... Also from what I referenced normal Ah for such a cell is 2.2-2.8Ah, so that's actually pretty sad at 1Ah. Factory 25ths indeed XD XD... Tho yeah. Nothings going far on that unless its a RC car... And not much of an RC car at that. vpoppv, feel for ya... batteries just aint cheap. If they were electric cars wouldn't be having nearly so much trouble price-wise... |
Been there, done that
I recently dismantled 70 some used lithium packs that were going to be thrown away and they were almost perfectly usable. The physical size is a 4/3 A. Digikey has plastic holders for them with terminals, I bought a dozen and I can look at the part number for you if you want. But if you just want a couple hundred cells to play around with they're sitting in a box in my house. I'd be perfectly willing to send them your way, just make me an offer. And I think they're all charged to boot.
For charging I use a Bantam BC8 with a harness I made myself. It charges and balances 8 cells at a time. Not ideal for you, but it does export the data to a computer so you can look at the charging curve. |
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Laptop batteries are commonly in excessively stupid battery layouts. Things like 2 2 2 1 (7 cell) 2 2 2 1 1 (8 cell) 2 2 2 2 1 (9 cell). One can easily guess that the 1's in serial fail LONG before the parallel pairs. And even when they're not and its 2 2 2 2 (proper 8 cell) a random worse battery can often pull a pair weak, and then the other one in the pair fails due to the stress. Although this happens a fair bit less often and usually takes many more cycles unless the initially failed cell was outright defective. At-least that's what I could figure from the dozen or so I took apart out of curiosity and a little research. Computer hardware is one of my... interests. Should be interesting to see what kind of C you can pull off these cells without them going up in flame or dieing in very few cycles. Though another problem that may arise is sometimes even same-cell count packs for the same exact model laptop, come in different amp hour ratings, and balancing all the different cells could be... Interesting. Other note, even if they were charged. Lithies, particularly the ones used in laptops? Bleed rather badly. Good luck tho be careful. Particularly with any sony cells. They're prone to occational internal contaminants that well, causes them to be extra volatile. |
I've collected some laptop batteries. I got a charger. Watch out Tesla.....
http://www.youtube.com/watch?v=ICzo_WU518Q |
Here's an article with Toyota and Tesla:
Toyota already building EV prototype with Tesla battery pack? — Autoblog There was a mention of a link between Panasonic and Toyota. As a side note, in my destroying of bad laptop batteries, so far I have found that the batteries labeled "Panasonic" tend to have a voltage (in the 4+ volt range) straight out of the bad battery pack, and only ONE of the batteries in "Panasonic" packs tends to be bad, whereas in packs without a manufacturing tag tend to die in pairs, and even good batteries tend to hover in the 2v range.... |
If you're willing to cover shipping, I'll send you a WHOLE bunch more....
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Panasonic makes very good quality stuff. I think the tricky part is getting all the batteries connected in series and parallel with those nickel tabs. Usually, people use a big machine that uses 2 pulses. The first pulse vaporises the impurities on the 2 surfaces, and the next pulse of about 3000 amps welds them together. I bet there's a way to do that that's similar to a motor controller. PWM can do anything. The pulse is for only needed for a couple millisec I think.
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I keep reading and re-reading about the Tesla pack on their website. This time, I caught a little error! Here's a quote from:
Battery | www.teslamotors.com "Sixty-nine cells are wired in parallel to create bricks. Ninety-nine bricks are connected in series to create sheets, and 11 sheets are inserted into the pack casing. In total, this creates a pack made up of 6,831 cells." Now: 69 (cells) times 99 (bricks) equals 6,831 But, if there are 11 sheets, that's 6,831 times 11 equals 75,141!!! At about 39 grams each, that's almost 3000 Kg. Since the pack weighs about 900lbs, maybe they just don't use the 11 "sheets" they talk about?:confused: Here's what one cell can do:p: http://www.youtube.com/watch?v=TtVXQEe8h8k Edit: That cell is uncharged, straight out of a "dead" laptop battery pack! |
Some more preliminary information:
Out of the 18 "bad" laptop battery packs: 3 packs had ALL the batteries showing above 3v. 2 packs showed ALL the batteries dead, but when the batteries were separated, they began building voltage. 38 batteries total showed zero voltage out of 131. From the little information I have gathered, I suspect that what is killing these packs is not the batteries but the management system. I'm too much of a newb to know how the $4 charger works, but it will only charge a battery that has decent voltage to begin with. I am able to get some batteries to hold voltage by starting to charge one battery that is "chargeable" and inserting a "non-charging" battery along with it. After a couple minutes of charging, a "dead" battery seems to hold above 2v for a while. Time will tell if they can ever be used again. So far, I have only seen 2 batteries that flat out won't take a charge, even when thrown in with a battery that WILL hold a charge. Of course, none of this really tells me the capacity of a battery. I was thinking of buying a CREE flashlight that uses these batteries and putting one in, then record the time it takes to discharge. That could take forever. Is there any form of cheap "capacity" meter out there?? |
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