I have one that’s opened like that, it wasn’t super noticeable
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We know for sure there’s no way to repair the pinholes right? Like you can’t just solder over it?
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I had no pinholes that I could spot after packs were taken apart. After a couple days with a hole the cell would show a low voltage or what?
These are exciting: https://batteryhookup.com/products/100-brand-new-lifep04-32650-3-2v-6000mah-cells?rfsn=1727885.2bd9ce&variant=35194643120290
6amphour is a lot for the size. “DIY” discount code gets u 10% off
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not many people are into this cell chemistry but by my math these are the most energy dense by volume iron cells available by a long stretch.
7.5 milliamps per square mm for these 32mm diameter cells
4.7 milliamps per sq mm for the common 26mm diameter A123 green b cells.
maybe 4.50 each with shipping for these vs the a123 at like 1.25 and the work to take them apart.
i like the label surprise to see them pull this off
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Out of curiosity, do you know which LiFePO4 [cylindrical] cells - or pouches - are the most energy dense by weight?
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dont see weights often. dont know. like to know. on the hunt for the smallest lightest like everyone
i guess they cant make cylindrical cells out of aluminum. why?
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Well weight is really the only downside of LiFePO4 chemistry when it comes to esk8. Usually but not always the weight is a bigger factor for me than the size. Although sometimes size is a factor as well.
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im a volume man myself
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Some extremely expensive “military grade” bullshit for flying needles into world leaders to deposit mind control nanobots I would bet.
Availability and price are kinda question 0.
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Those certainly use Lipo and not LiFePO4.
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Those look interesting, but only rated for 18A continuous? Weren’t the 26650 A123 cells rated for like 70A?
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Good question, if I’m going to use LiFePO4 then I don’t expect to have concerns about discharge or charge rates being too low or even close to too low
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my guess is that the A123 cells just got the special super power sauce. 18A makes sense to me given the high cap.
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Really hard to use huge cells that are probably good for like 10-12a output considering voltage sag. Need like 6-8p of those fatties.
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hey guys, I’ve got a pack with used A123 26650 cells, 14s2p, one of my pgroups is charging way faster than the rest.
I manually balanced them just 2 days ago, every pgroup to 3.6v, now pgroup 10 hits 3.75v straight away, while the rest are at 3.4.
When I unplug the charger the BMS balances it out (quite quickly, which is a bit suspicious since the LLT BMS only does 50ma balance), but when I plug it back in same thing.
I guess I’ll just swap it out for another pair (I bought 96 cells out of a bus, 12s8p, for 120cad. it was tested to have about 17ah left, from the original 20 or so), but I can’t figure out why it would be charging so much faster. Any ideas?
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i just realize that it’s probable that the pgroup in question is only 1cell due to bad spot weld… I guess if you want something done right you gotta do it yourself
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yeah that’s a pretty good idea. Capacity test through balance leads?
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How are u all testing capacity on these used cells? Trying to find an easy way to do it before assembling the battery. In theory should be able to charge or discharge even a low current and for little time and compare to a graph of what a new cell voltage would change. Would be easy electronics and cheap but way beyond me. work by registering the starting voltage, charge or discharge maybe an amp hour, Then compare the voltage to some standard.
Otherwise best I can think is to throw them all in parallel to get same voltage then discharge individually with a simple discharger w a known discharge rate, and compare
Had another cell that somehow I crushed and emitted the electrolyte out the same area they blow open when they’re over stressed. (The positive that looks like a negative). Smelly.
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Smells like? chemicals?
like that hot metal acid smell?
At first thought was epoxy but sharper smelling. Kinda like a cheddar to a Gouda. Then I had to stick it right up my nose for a solid whiff to make sure. Then I thought maybe was dizzy.
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