I read your article in HP113 about battery-powered lawn mowers and it brought to mind how I handle charging mine. Two years ago I decided to move the mower out of the garage to a shed away from the house. To charge it, I had to move it back to the garage to get the electricity. What a pain. I decided to add a solar-electric system to the shed, and bought a pair of small, 12-volt, 5-watt modules.
My mower is a Black & Decker. The wall wart is merely a 120 VAC to 24 VDC transformer, and the charge control is built into the mower. I cut the wires from the wall wart and spliced the panels in series to the mower input connector. This should work for almost any device using a transformer on the wall, if the solar-electric module and transformer output voltage are approximately the same.
Greg Sykora • Livermore, California
That should work fine as long as the module is small, and the mower does in fact have internal charge regulation. The mower has a sealed battery, and overcharging could damage the battery. If a cordless mower lacks internal charge regulation, then an external charge controller may be necessary.
Michael Welch • Home Power