discharge problem

[korn_2956]

i bought a cheap venom lipo, 2s 2000 mah. problem is that one of the cells stops discharging at 3.66v. it did it in my rig(saw it on my lipo alarm that went off when the one cell was at 3v and one was at 3.6) and so i thought maybe a couple cycles would help so i charged and discharged a couple times today and it balances and fully charges fine but when i discharge it the one cell stops at 3.66 everytime while the other continues to discharge. i only get about 1700 mah out of it because of this. i know its a cheap battery but is there anything i can try maybe to fix it or is it always gonna do this. also why would it do that. maybe its not the 3.66 cell thats bad, maybe the other one discharges from 3.66v to 3v to fast and the cell that seems to stop at 3.66 is just does that because its discharging normal and the 3v one sets the alarm, what. i dont know im kinda new to this stuff. any ideas on a fix and a reason would be awesome. thanks

[Charlie-III]

The cell that drops more is weak, it tanks too fast as you guessed and it causes the LVC to kick in.
Doing more running on it "may" bring it back, but it's doubtful.

If you want to try, take the pack & charger outside and charge/discharge it @ 1.5C (if need be, double the mah rating of the pack when setting the charger up), you will either possibly clear an internal issue or burn it up. Keep in mind this is a good way to start a fire/destroy the pack. But it works at times.

[korn_2956]

ok but why does it stay balanced all the way down to 3.66 and then it dies.

[Charlie-III]

Originally Posted by korn_2956

ok but why does it stay balanced all the way down to 3.66 and then it dies.

It likely has a small short internally which shows up under load. I see it all the time with large UPS batteries (I work in the UPS battery industry). The battery/cell can look great, until you discharge it.

[korn_2956]

ok thanks man. ill try the 1.5c deal later with an extension cord in the neighbors yard

[Charlie-III]

Originally Posted by korn_2956

OK, thanks man. I'll try the 1.5c deal later with an extension cord in the neighbors yard

Bring marshmallows......

[Charlie-III]

BTW, your thread title makes me laugh every time I read it, sorta a "go see a Doctor" kinda title.........


[Thinking along the line of Frank Zappa's, "Why does it hurt when I pee?" sorta thing....]

[korn_2956]

haha yeah didnt think about it like that.