Hey Adam, glad it helped! I usually caution folks buying the cells online. Lots of stuff out there of varying quality. Brand names such as Sanyo and Samsung are trustworthy. But if you want to buy online, here’s a link to what I would recommend: amzn.to/3PyP7VI These are 3000mAh (3Ah). You can go less than that, but if you’re going through the trouble of rebuilding this battery pack, I wouldn’t go below 2500mAh (2.5Ah). Let me know if you have any more questions or if there’s any way you think I could be helpful. 👍🏻
The trouble with this pack was simply that it had been cycled hundreds (possibly thousands) of times and no longer lasted as long as desired after being fully charged. So out with the old cells and in with the new. Some chemistries of lithium cells decrease from from 100% capacity to 40% or less after 1000 cycles; while others decrease from 100% capacity down to 80% after 1000 cycles. (These numbers are just for example only and are ballpark at best to convey how the capacity of lithium cells diminish after so many uses/cycles)
You know damn well @zko7022 that lithium ion cells fail internally all the time. Don't even try to act like it's even possible anything other than cell failure.
