re: Pic added for illiterates;Electricians: can I change a 6 volt motor

I'm just guessing but it sounds like your battery has built up "memory". I don't know exactly how that happens, but nicad batteries tend to adapt to how you use them. Google can probably explain the science. But if you don't fully discharge them before recharging, they tend to only last as long as the time period you discharge them. In other words, if you are in the habit of taking it off the charger and only using it for 10 minutes at a time, eventually a charge will only last 10 minutes. It's better to completely drain the battery for it's full duration before recharging. To some degree you can usually get some of that back by discharging it all of the way and starting over. Turn the car over on its back (wheels in the air) and jam the throttle so that it runs until it is completely dead. Let it rest (without charging) and do it again until it is good and dead, then recharge. Try that a few times and see if the run time gets longer.

My son had the pw jeep and the battery went bad. I bought a riding lawnmower battery and cut out the engine compartment so it would fit. That worked well. Of course that was 12vdc, but perhaps you could do the same with a 6vdc motorcycle battery. Just be sure it is rigidly installed so it doesn't tip and spill acid.