How to Save Money When Buying 21700 lithium power battery
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The automotive consumer e-target is/was $60kWh to be competitive with ....DogDipstick said:
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A mAh cell of 3.6v nominal ( 4.2(aH) x 3.6(Vn) ) = 15.2 watt hours. A single gen4 Chevrolet Volt cell holds ~90 watt hours each.
What do you figure is the kWh rating of each of those 9 Chevy Volt cells ?
I purchased 88 cells, in a 44s, 162v nominal battery. 8,900 watt hours. Eight thousand, nine-hundred, watt hours. Half a pack. Came in a OEM GM box that said " Property of GM" and " MADE IN TE USA"... a very very fancy shipping box that bolted the modules down and straps closing the box and fancy warnings all over it... You can see the pack, labeling, and the embossed plastic ship container in the pic below....
The kWh number.... It is printed on a label on the side of the pack. By the factory. The factory is in Ohio. Where the modules were assy. The factory puts a sticker on teh modules, and teh pack as a whole, and tehy each have their own Chevrolet part numbers with Julian dates. A factory employee, is tasked with this chore, or a machine, that places this sticker, on the pack, before the pack is shipped out to its final destination. The sticker is probably printed on a roll in another part of the factory, using a computerized system.
I also test on my Powerlab to make sure they meet the mark.
Being you have yet to answer Hh's post it may be that your post is wishful thinking. Being you bought 9 Chevy Volt Li-ion cells is it possible for you to post a photo of 1 of those
IT WAS 88 cells, in a 8.9 kWh nominal config.... I have purchased over half a thousand of these ( Chev Volt) cells, and sold most of them..... Not very "wishfull"... But very easy actually. You only need to have money to purchase them, no wishful thinking involved.
Being as I have answered.
Would you like a photo of many cells? Here. I do have pics of like fifty or sixty sitting on tables, waiting for the sale.
So, 140$ a kWh is an unbelievable bargain considering ....
(YOU CAN ALSO CLEARLY SEE THE OEM "2kWh" LABEL ON THE EbAY PICTURE, and JULIAN DATE. IN the picture from eBay, that you posted.)
This Lithium Ion Chevy Volt 48V 2kWh Battery w/BMS is $590 on ebay ...
https://www.ebay.com/itm/?hash=iteme54d0c:g:IRoAAOSwV51hdw1d
THIS module (the eBay module you linked... ) is actually overpriced, used, and no real history, with questionable specs... ( ripoff imho). It is one of the earliest modules, you can tell by the plate structure and color of the fiberglass plastic. I buy a kWh of those cells, used, ( early gen) for 80$ a kWh. He has a mid sized module in the pic... So that is 2kWh. You can get a 3kWh module form a later car pretty easy if you look, for that 600$ price for sure. Like I said, Art at Greentec advertises those 80$ modules on the ( this forum) forum in the for sale section. I show two ( 1kWh) early modules in the pic below.... Running my datalogger. Those were 80$ from Art. They are the LG P1 cell, a 14.5Ah cell that holds the least watt hours out of all the cells in the Volt. There were four revisions of the Chev Volt cell / pack choice. I have tested and used all four of those part numbers in ebike builds.
He really does not know what he is talking about. EVERY spec is wrong. They are NOT 17Ah ( really 14.5Ah) , nor from , ( from or ) nor is it 50Ah oem. ( 45Ah oem) ... NOT LiMn2O4 with LiNiO2, ( they are lipos, not lions). ... NOT 48v nominal ( really 44v nom. )... Grrrrrr.... NOT 3s12p.. Jesus how could you get that wrong and have any sort of faith in your numbers. Lol.. This is why I do not buy off eBay. Noooope.
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Go find the most expensive, lied about, Chevy Volt pack in the world....? and that is what ya got. Like going to out to eat... and expecting a Sirloin burger... and paying the prices of a of a Sirloin burger.. only to get home and find out the "burger" was really a McDonalds fish sandwich wrapped up in a burger wrapper..... Sold to you, for you thought, you were to get a savory Sirloin burger.. Plot twist.. It was really a McDonalds. Trying to rip you off and get as much money for their ( fake Sirloin) burger as they could (at that moment)... I use honest, reliable, business men, who run real " restaurants".. (dealerships)... And? When I pay for a Sirloin burger... that is what I get.. a Sirloin burger. I dont do "McDonalds" anymore.. (a stomach ache).
It is a 12s3p.. NOT a 3s 12p.. Bahahahahahahahahahah. He does not know what he got, .. Lol. Probally just knows they are popular, and sell, for powerwalls and ev diy builds ( like I do).
The cooling plates and teh orings have been removed, and a shipping band installed around the top to keep them together. Clearly shown. Someone has been inside that thing, and it can never go in a car again. Molested module for 600$, when you could buy a unmolested module of GEN2 cells for that price.
Lies, for sales, that pisses me off eternally.. He does not know at all what he got. Lol.
THIS GUY at least tells teh correct config, even though he lies about the capacity ( not 27Ah cell, but a 25Ah cell)... 600$.
https://www.ebay.com/itm/?_trkparms=amclksrc%3DITM%26aid%3D%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D%26meid%3Db23fa4ffabde0c3a15e7%26pid%3D%26rk%3D2%26rkt%3D5%26sd%3D%26itm%3D%26pmt%3D0%26noa%3D1%26pg%3D%26algv%3DDefaultOrganicWeb%26brand%3DLG&_trksid=p.c.m-1
( I have tried to purchase, and have paid for, this particular module a couple of times.. but he keeps on cancelling the sale, for I am pretty sure he knows who i am, and that, i might prove his specs wrong and request a return.. or compensation.. for his lies: and uneducated, incorrect, ambiguous, description... ( ...that, which I would, do, given that chance.) The Chevy published data does not coincide with ANY of his data... and I have asked him about that, several times without response... in the past, through the eBay messenger.... )
They did discontinue every revision up to the rev.1.7 ( the program Chevy calls the newer Voltec replacement battery in the Volt.. the " 1.7 chemistry update" (denoting the LGX P1.7B cell used). This is what they put in the older cars nowadays, the earliest cell numbers were retired from the warranty program last year.
They range from about 60wH to 92wH per cell in the eight years of the car. I have a switchboard that holds the tower of power cells and the datalogger and a ton of Panduit alligator clip binding posts that I can configure for any sort of testing connected tot he chargers 40 pins, the balance x 32 and the main x 8 leads. Yes, it can be a rats nest of temporary wires for the test of mass sections of module or many cells at once.
.... a photo of 1 of those [pouch?] cells next to either an or cell so we can see the difference in size ?
Sure, I have tested over a thousand.... They are 0,25 x ~6 x ~10... If you really want a pic here you go.
Would be interesting to know how you went about testing the cells for c/d capacity, IR, etc.
I use a Revolectrix Powerlab, a four channel, 32s w datalogger. I run it with 6kWh of the car cells. I can test up to 32 cells, or 32 groups of cells, in series, or not, at one time, up to w ( 40A each, so yes I can do 1C testing of cycling charge/discharge on a datalog). Typical cycle is a charge from storage voltage, discharge cycle, charge cycle, discharge cycle, and back to storage voltage, all on a datalog. Logs each channel individually. Very clearly shows the collumbic efficiency and the IR, capacity, and curve, of the cell. All data can export to Excell for easy manipulation of the graphs if you dont want to use the Powerlab native graphing features ( Excell is better at this)... Real 1C rate determination through PID loop controlling the current...
The automotive consumer e-target is/was $60kWh to be competitive with ....What do you figure is the kWh rating of each of those 9 Chevy Volt cells ?Being you have yet to answer Hh's post it may be that your post is wishful thinking. Being you bought 9 Chevy Volt Li-ion cells is it possible for you to post a photo of 1 of thoseSo, 140$ a kWh is an unbelievable bargain considering ....This Lithium Ion Chevy Volt 48V 2kWh Battery w/BMS is $590 on ebay ....... a photo of 1 of those [pouch?] cells next to either an or cell so we can see the difference in size ?Would be interesting to know how you went about testing the cells for c/d capacity, IR, etc.
battery advice needed
Been pondering this and I don't think I have great answers, but I do think this is worthy of doing it the right way and thinking it through carefully because we're not talking about a trivial amount of current. Are you modding/creating in a host, or altering an existing light, or just trying to save pennies on the batteries it was designed for?
Ultimately, it makes so much more sense to change the host parts in a way that they will take ordinary-length cells, rather than having to change each cell each time and attempt to get their lengths consistent.
If the tail spring board is easy to remove, totally try a longer spring there that can handle the current and retain all or most of its height while doing so over time. If that can/should be done on both ends, assuming the driver board is compatible and accessible, then do that...or perhaps a button/slug can replace a spring.
I really really do not recommend soldering cells. Spot welding is the way to go, when done correctly, but soldering adds a lot of risk especially on the negative end, and you need to add a considerable amount here, not just a little dab. If soldering is the way you want, then do it on the positive end/cap and be careful about it so you don't short, and quick about it so you don't damage seals or cause it to vent. Overheating the negative end can spell bad news for the cell either in performance or safety and that's true of these high drain cells that can take a lickin' as well as it is for ordinary lower drain cells that are somewhat more sensitive. And of course if you were to use protected cells then you wouldn't be able to solder on the negative end anyway. I've soldered buttons and blobs and tabs on dozens of NiMH and NiCd batteries over the years, but I won't solder lithium...did once, but all things considered it's not worth it to me unless it's just a blob on the top to make a small button but I haven't needed that in any of my lights in a very long time. I just wonder about all of the heat and current in this application. Plus soldering to nickel can be unreliable even with scuffing. We've seen springs literally melt from high current that was done wrong, and cells that overheated to a dangerous level through current or accidental shorts, so I wouldn't put a lot of faith in solder here even though their melting points are above what we'd expect to see.
I searched the forum for a bit but couldn't find posts that I think I'm remembering from the past about magnets and resistance/current limit. It may have been from Dale (DB Customs) in some thread, really can't remember. But I was thinking that there was a medium-level of current that was a practical limit for magnets but of course most who use them are using tiny ones as buttons/spacers, not thicker ones to fill up space and cover a larger cell. I would try some kind of slug to use as a spacer on the tail end if you don't want to modify the light itself. If nothing else, a copper pipe cap could be trimmed and filled with solder - a 1/2" is around 5/8" o.d. and I think a 3/4" will be too wide without a fair amount of sanding. I looked on Amazon to see if there were any convenient discs/slugs and there are lots of jewelry stamping blanks but most are way too thin - thickest I saw was 1/8" and they were pretty expensive for a smaller quantity of 10 or so. Washers and bushings present the problem of the spring going in the hole, so you don't get the effect you're after. If you have a very well stocked hardware store there are copper bolts that exist and you could cut the head off of one and grind it to suit....a little pricey but you could do the same with an electrical split grounding nut thingy. Heck, really for this purpose I think aluminum would be fine and if you can score a short length of 3/4" bar you could just trim pucks from it.
So the cost of parts and consumables, repeatedly for a trio of cells and more cells in the future, plus risks that are not zero...sounds cheaper and better to just spend a couple extra bucks on the ridiculously priced cells that fit the design of the light...and don't buy lights like that again. :)
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