I have some old cordless drills (and tools) that are a pain in the ass to get batteries for, the batteries won't hold a charge, etc. What I did is to attach a pair of (homemade, small) jumper cables from a voltage source to my cordless drill. So, with like a 6 volt or 9 volt cordless drill, I jump power to it directly from a battery charger (set on 12 volts). It spins that drill like a top, plenty of power and plenty of torque.
If you got an old cordless drill your going to pitch in the trash, expose the electrodes on it and slap a power source to it --if nothing else take a 6 volt lantern battery and jump some power to the drill. Cut up an extension cord and put alligator clips on both ends of the cords. Jump the voltage from the battery to the drill. If it dont go, then reverse the wires. If that works, now get your battery charger and apply the voltage from that to the drill. Of course, when you are done (playing for each session), unplug the charger from the wall. Have fun and get more mileage out of old cordless tools.