LIPO - out of balance cells?

[Cardnim]

Hi all,

Im new to lipos and have just received my first charger and 2 batts (one brand new Speed Power, the other an older 2nd hand GM.)

Good practice with NiMH was always to discharge the cells before charging again (to prevent cell capacity memory)

So, plugged in my 2nd hand GM lipo (2 cell, 5400mAH, 45C) and plugged in the balance board that came with my charger.

Set the discharge rate to 1.0A

It went for 73mins but by the end, cell 2 had dropped out of sync with cell 1. Before that, they were much the same.

The charger ended the discharge, with the following spec:
- cell 1 - 3.42V
- cell 2 - 2.80V

I have read that discharging lipos beyond 2.8 is very dangerous, but I am surprised at the difference in voltage - surely the balancer should have prevented this? (or at least stopped discharging cell 2 while continuing to drain cell 1 till it was level)

Can anyone shed any light on this? The Internet is filled with scare mongers who say "my granny once looked at a lipo funny and now she is on fire" - so its hard to filter the fact from fiction.

Thanks as always guys.