I forgot to switch of the power switch to my Sherman last night and now discovered that the battery is flat...registering approx 1.5 volts...My GO-PEAK charger won't recognise and charge the battery...A quick search in the garage revealed an old 500 ma charger from my model flying days, I've hooked this up to the Batt to raise the voltage to a point where the GO-Peak will recognise it...So far so good the Go-Peak is charging it now and all seems fine...I'm unfamiliar with Ni-MH Battery packs and the long term effects of virtually flattening them...Do you think I've harmed them in any way.