i got a 4800mah off ebay
it is half transparent and indeed you can see 4 cells inside.
the balance plug reads 3.85v for each of the 3 first cells, and 0.05v for the last cell.
the main wires reads 11.5v....
which is clearly the 4th cell is totally empty, or it has some bad connections there inside...
what would you advise in assumption that i don't return it to the seller ?
Replies
Sorry about your purchase, Seller should refund your money, I would not return it, as it is al fire hazard now.
Please, NEVER !! buy a used lipo unless you can personally test it,
Even then you will not be able to gauge it's remaining life,
Just buy the new Nano technology types with high charge rate of C4, These seam to have the longest life and are a little more tolerant of abuse. With lower internal resistance they don't heat up as fast too. Charge at 2C vs 4C for longest life.
E-Bay should ban selling used lipos. just like ammo.
When one of these batteries burns or explode in a post office or delivery vehicle USPS may stop shipping them.
If you convert to a 3 cell be very careful, only work on one exposed terminal at a time to prevent accidental shorting!
I'm sure many people will tell you, you can recover these cells, but with the amount of potential for explosions and fires I don't think it's worth the risk.
If you are very confident you are completely sure you know what you are doing, you might want to make the battery a 3S and not the 4S it sounds like you have.
Regards
Martin