Hi...did you discharge your pack below the low-voltage cutoff? My 48V Nicad pack has no LVC control in the pack, unlike a lithium battery pack, so I need to use the CycleAnalyst from ebikes.ca to set a low voltage cutoff in the controller. Ebikes.ca recommended 41 volts for a 48 volt pack, and it will scale back the current, as the voltage drops to this level, to hold the pack voltage around a minimum of 41 volts. If Nicads are discharged too low, you can get cell reversals and damaged cells I understand. I'm not sure of the LVC setting for a 36 volt pack. Otherwise, Nicads are pretty robust.