I took apart 2 cordless drill batteries and there were 13 cells in each one, which were Ni-Cd 1.2 volts each. Also there were the numbers C DE35ND on them if that helps at all. I cut 3 off in order to form a 12v battery (it was originally 15.6v) but I dont know how I can safely charge it. I no longer have the charger that went with the drill, but I was wondering if I can just use a wall adaptor to charge them or do I need a better charger? All comments and answers are greatly appreciated!!!