Re: Dry cell recharging
It certainly is possible. When I was about 11 years old, an electronics magazine published a very simple circuit that rectified a 50hz voltage and put it through the cells with a high-wattage resistor in series. I used it to charge the 'D' cells in my bicycle lights, they lasted about 2 to 3 hours on a charge (once the initial life was 'used up') and seemed to withstand about 5 recharges before the time dropped significantly.
I now have a commercial MCU controlled unit that definately does work. Torch cells and similar high-usage cells are the ideal ones to recharge. If a cell is drained very slowly, for instance in a remote control, it will usually not recharge as the electrolyte itself has degraded with time.
If I can find the circuit, I will post it, but we are talking about 25 years ago! I'll have a look this weekend.
The key, I remember, was to charge in current pulses, *not* continuous as this could boil the electrolyte. I don't recall the voltage used. Maybe just experiment with low rectified (no smoothing capacitor) AC voltages from a small transformer, remeber the resistor to limit current, until you succeed? Start with a set of equally discharged cells and charge each with a different current, then see how long each lasts with a bulb.
Cheers,
FoxyRick.