lost a cell in my lipo 8000 today..help!!

[billmck]

wow, i keep an eye on the balance of my packs and today i noticed that the neg side of my maxamp 8000 was lower that the positive side. i cut the heatshrink off to find a pack just starting to puff and i bent the lower pack. where it puffed was twice the thickness within a 1.5 inch area on the corner. that probably happened when i was put into the monster truck class and got slamed pretty hard after leading the qual for 3.5 mins. ok, enough about that...question is can i just repair this pack by replacing the 1 puffed cell and the other suspect lower cell which is kinda bent? looking for you lipo guys here.....


bill

[tcolesen]

You can't just replace the cell with a new one, for the reason that a new cell will give slightly better performance than the one that is being replaced. Since it will give more capacity, it could cause another cell to dump sooner, possibly damaging that cell.

[billmck]

You can't just replace the cell with a new one, for the reason that a new cell will give slightly better performance than the one that is being replaced. Since it will give more capacity, it could cause another cell to dump sooner, possibly damaging that cell.


well, the pack isn't that old, in fact, i have less than 20 runs on it. so i think that it will just settle right in, who knows,,time will tell. thanks for your help man..

bill

[tcolesen]

Personally I wouldn't risk it. 20 runs can lead to a 5% difference in capacity in the long run, leading to an accelerated deterioration rate.

[billmck]

ok, i guess i'll just get another 8000 pack. which would be better, the maxamps or thunder power, or is there something else i should get?


bill

[tcolesen]

Thunder Power is lighter, but also a lot more expensive. The Maxamps pack is a much higher value.

Are you using proper LVC and balancing equipment? If you're not, it might be worth it to help prevent puffing.

[billmck]

Thunder Power is lighter, but also a lot more expensive. The Maxamps pack is a much higher value.

Are you using proper LVC and balancing equipment? If you're not, it might be worth it to help prevent puffing.

i'm pretty sure that the pack was damaged from getting tboned from monster truck(those guys at my local hobby shop don't care). i got the loa from apogee and i charge each side of my pack seperate if it isn't equal. it takes longer but it gets balanced. i should get a seperate balancer though.

on a side note, yesterday, the local hobby shop had a trophy race and i was the only 10 st truck period and i got 2nd place trophy in the monster truck A main! - yea.. i ran with them, the ran from them, funny they couldn't catch up. 20 min mains are fun!!

bill

[JCSS]

"puffing" is the cell venting internally. ie- ruined.

And when you buy junk cells like MA's, you need to balance them after each run and strict LVC.

[tcolesen]

And when you buy junk cells like MA's, you need to balance them after each run and strict LVC.

Why do you define them as "junk"?

[billmck]

"puffing" is the cell venting internally. ie- ruined.

And when you buy junk cells like MA's, you need to balance them after each run and strict LVC.

you are 100% right as far as my 8000 pack is concerned. i had to charge "each side" because i saw imbalance from day 1, so that made me concerned. the best thing i had available to "balance" was to charge each half of the battery pack -center tap and ether pos or neg. and compared to my orion lipos, they bleed down like nicads.. so tell me, what other options do i have if i want another big battery???


bill

[Maxx42]

I use 2 maxamps 8000 2s packs in my emaxx with a 7XL motor and never had a problem with the cells falling out of balance. I do use, however, the hyperion balancer when charging. Also when I plug the balancer in right before charging, the balancer says that the cells are in good balance all the time.

[khyron]

Why do you define them as "junk"?

Probably because he paid a lot more for something else. ;)

[tcolesen]

Probably because he paid a lot more for something else. ;)

That's a logical explanation :p.