Lipo / Dead Cell

[Serum]

you charged it without the balancer and then it went from 4 to 0 A?

Here is something you can do to test, but you need to be VERY careful; Pull the balancer plugs slightly loose, so you can put the pins of a multimeter between them, and measure the voltages during the charge process of the bad cell. Compare them to the good cells, and if they differ a lot, it seems that the cell is dead. Since a charging process is happening in series, and if one cell isn't charged at all, the cell must be dead or completely full. Simple by measuring its voltage you know which one of the two option it is.

Do you balance the packs every charge process or every now and then?