AmpEater said:I broke down my 8s 5.8ah 25c turnigy pack with a slightly puffy cell. Ended up dropping one on the concrete floor, so that leaves me with 6 good cells to cycle test.
I'm thinking of a new set of tests
Cell 1 - 4.3v -> 3.0v at 4c
Cell 2 - 4.2v -> 3.0v at 4c
Cell 3 - 4.1v -> 3.0v at 4c
Cell 4 - 4.0v -> 3.0v at 4c
Cell 5 - 4.1v -> 2.7v at 4c
Cell 6 - 4.1v -> 3.3v at 4c
So I should be able to get a good idea of the effect charging voltage has on cycle life, and a good idea of what deep versus shallow cycles do with the charge voltage I expect to run (4.1v)...unless testing tells me otherwise that is
I will start cell 1-3 going on their loops to destruction tomorrow. Interesting note - I'm playing with the slightly puffy cell doing 2c cycles from 4.1 - 3.3v and the capacity is declining amazingly fast. It was 4.6ah yesterday, and maybe 10 cycles later I'm seeing 4100mah, 3850mah, ??? (I'll know soon, I'd guess bet around 3600)...it seems to be loosing 2.5% of its capacity per cycle)
Do you have a good hint on what the cause of the puffiness might be? I hope it's preventable, but it kind of sounds like its random so far. If the cause could be found, then maybe "puffiness" could be prevented.