Well the cells I got are good. If they didn’t have new good deals on better cells I’d have no problems.
there use to be “POWERWALL” for 10% but i don’t think it works anymore
btw very safe carpet capacity testing
DIY. just use DIY.
20S1P or 10S2P for $200 @Arzamenable
12S2P for $250 and you get 1 spare
he links these
reluctant to make Jag35 thread
6200MAH 50C 3.7V LIPO POUCH CELL.STEP (64.6 KB)
200A discharge 3.7V 8AH flat pouch lithium ion cells
I made some guides for using the TE foil crimps here, just select to show only my posts you will see.
Thanks for the link, that circuit board will hopefully be a good way to use these cells.
50C is over 300A and, IMO, is a spectacularly exaggerated rating but you can probably pulse them pretty darn hard and not have to deal with too much voltage sag and heating.
Would love to know what their cycle life is. LOL…no one ever seems to care about that. I guess as long as the pack runs for a while it’s not a big issue for the price. Personally, I rather pay more and not need to replace the pack for years but I think I am in the minority regarding that. …end whining…
I love the idea of using those TERMI-FOIL connectors but I’m not sure how they can be nicely isolated from bouncing around in use and snapping the tabs. I guess lots of foam would need to be involved.
Hmm…or a clever little PCB with tabs the barrels can slide onto and then get soldered? Probably too hard to get a good current rating that way though without a silly large PCB.
Soooo… if some random Duck happened to get his hands on like 50+ Hoyt 10s1p Samsung 25r battery modules in various states of disrepair, and wanted to sell them off for really really cheap, would anyone be interested?
Just, you know, hypothetically speaking
but there’s no discharge graph for them anywhere and especially with them having such a huge claimed voltage range going from 2v to 4.1v i wonder what i should be charging and discharging to if I want them to last. The cells arent on K2’s site and I wrote them and batteryhookup looking for it but havent heard back yet
i tested them with my constant load tool and i got 3650mah with a 3 amp discharge and 3710mah with 1amp discharge between 2.5 and 3.6v. The cell was warm with the 3 amp discharge…thats not good is it? @Battery_Mooch
That 4.1V rating is preposterous. It’s an LFP cell and 3.65V is as high as you want to go. That (useless) “max” rating would be like charging to 4.65V with standard Li-ion cells…ridiculous.
If you want your cells to last then don’t come close to even what the “standard” low voltage cutoff and charging voltages (2.5V - 3.65V) are. How much higher than 2.5V you want to stop at and how much lower than 3.65V you should charge to will depend on how much capacity (range) you are willing to trade off for extended cell life. You’ll have to do some tests.
A lot depends on what you call “warm” but if those are actually 12A cells then they would get warm when being run at 3A, 25% of their rating. At 12A they would be blazing hot…this is normal. They’ll be even hotter when next to other hot cells and hotter than that when all wrapped up in tape/fishpaper/shrink wrap.
You’ll have to run some tests with a small wrapped up pack or just go ahead and build your pack and then see how warm the cells in the middle get. A lot will depend, of course, on how much current per cell you will be drawing. I can’t predict how hot they’ll get for the pack you want to build though, you’ll have to test it or find someone who has used these cells in an esk8 pack.
id planned on potting them too making it even more suspect with that heat. ill add as many in parallel and series as i can to reduce heat and minimum resin.
i normally use between 3 and 3.6v with lifepo4.
K2 says this is the data sheet for the white 26650s
Batteryhookup says they’ve never heard of lifepo4 going to 4.1 and say go to 3.65 max.
I discharged one at 3.5amps and doesn’t warm up noticeably until hit 3v and then starts warming. Im guessing that would be a limit if you want the cells to last the longest.
To me these are the best cells out there if you can accept their power ability.
hypothetically, what is really really cheap? like cheaper than building my own 6 10s3p packs cheap? x)
I would think he wants locals to take some. I would be interested in practicing my teardown skills
if u get those a123 cells from me I’ll cut the cost. Cheaper than if u get them yourself and have to disassemble them from the packs.
I’ve torn them all down already. They show 97.5% capacity.
now thats interesting! i was just gonna grab up 200 p26a and sell off the leftovers. im bothering my investment guy today to hurry tf up putting my money in my bank so i can get to actual purchasing phase, but i could probably swing that this check even if he does take forever xD ill message ya!
unrelated: bro idk what wizard runs my account with fidelity but that shit goes up at least a thousand a month not including my actual contributions.
Lifepo4 for life!
Batteryhookup has brought me to the light and it’s not a cell in thermal runaway.
Won’t bother charging past 3.4v anymore or even below 3.2v and almost all the energy is within a nice .2v for consistent power and speed.
This is what makes then totally awesome in aonewheel, but bad the highly valuable range. 24S1P got mer just over 10 miles on and off dirt trails.