Getting rid of old lipos...

Physical damage is obvious, but just getting warn out is harder to notice.. although it can be argued if you can't notice it then its not a problem.

As cells age their internal resistance will go up and their capacity will go down.... and really I guess instead of 'age' it shoudl be more 'as cells wear out' or something. In any case less runtime, packs warmer after use than they used to get, maybe puff up a bit more, less punch when you pin throttle. All the changes are slow though, so it can sometimes be hard to notice them until you get a new lipo and go "wow this is so much punchier than my old pack".

A nice feature of fancier chargers is they'll meaure cell's internal resistance while charging. So you can kinda keep track, new cells maybe 10 mOhms. Older packs all cells will be 50 mOhms. With RC cars/trucks lipos last me forever. With quads I've yet to have to throw one out because its getting old. All of them end up being damaged in crashes...

Well the 5 lipos I was getting rid of:

One 4S got pretty bent up after slamming into the ground at full speed with warpquad, oops. This happened like a minute into flight, lipo was still at like 3.9v/cell. I put lipo in ammo can to dispose of later on. Month or two later now I opened ammo can last night and it smelled like chemicals and that bent up 4S lipo that was charged is very dead, wouldn't light up light bulb or power up lipo alarm. I did not go get multimeter.

1 4S lipo again after some crash it got damaged, but I didn't even until I went to charge it and: http://i.imgur.com/UY83VFo.jpg Cell 1 was at 33mOhm resistance while 2-4 were all at 5-6mOhm. Looking closer at pack there was a little cut on the side, it didn't look like it had actually damaged the cell but apparently it did.

1 6S pack is a few years old from 1/8th scale buggy, onces I was driving around without body and I forget what happeend except lipo got ejected in a crash and balance lead was cut up a bit. I still used it for awhile but its now years old, resistance was like 50mOhm/cell, which is really really high for a 3300mah pack.

2 3S packs, I bought 2 lipos and both were always flakey, I think it was a bad batch or something, it is not a bad brand but both failed way too early. First one I was flying around and alarm goes off, land and two cells are at like 3.6v and one cell is at 2.5v. I was unsure how that could have happened. No physical damage. I then ended up not liking 1300mah fora 250 quad so I ended up not even using the 2nd one that much and it just sat there. Few months pass and I grab that lipo and 2 cells are still at 3.8v storage and the 3rd was really low, I forget exactly how low. But fuck those packs, they were garbage.

/r/Multicopter Thread Parent Link - i.imgur.com