Two B&D 18v NiCad batteries. They both fit my old 18v B&D EPC18 drill, but only the 2-pin/prong A18E battery works. The 3-pin ML:HPB18 is completely dead in the drill, but, after testing, seems to be fully charged (16.6V = OK for a not-new battery?).
So, is this because the batteries are...