John Hermans tells us how he made his favourite pastime solar powered.
I love drilling holes. I’m at it every day, using one of at least eight different machines. But the two that I use most regularly are my 14.4 volt keyless and cordless drills. They were given to me by my tradesman mate Tom, who upgraded to the 18 volt version, with more grunt and storage capacity.
The nickel metal hydride battery packs that came with the drills had been given a good run already and refused to accept charge after I’d used them for about a year. My preferred replacements, lithium ion batteries, would have cost so much that I could have purchased a whole new drill with new ni-cad batteries. This option being against my principles—I wanted to keep these perfectly functional drills working—I ended up buying two NiMH batteries online at a competitive price.
Two years of drilling went by and my replacement NiMHs were suffering the same fate. Using any one of four similar chargers, the charging period would only last for 15 minutes or so. Lifting the battery up and dropping it into the charger again soon became futile.
I decided to have a go at charging the batteries using solar power. A couple of years ago I was the happy winner of a 17 volt, 20 watt solar panel in ReNew’s Sustainable Sheds competition. [Ed note: read all about John’s super sheds in ReNew 107.] The output terminals of this panel were connected to the positive and negative terminals of the NiMH battery packs. They were given just a few hours each of high quality East Gippsland sunshine and wow, they have all taken the charge, although admittedly at less than their initial capacity. I now have four very functional battery packs again. The solar panel puts about one amp into the battery, so the 3Ah battery needs a good three hours to complete its charge. I’m a little unsure how the battery will respond to being left on the solar charger all day, such as if you fail to time it right. I try to start the charge mid afternoon, so the fading light tapers the charge.
Thanks ATA—what a saving in cost and resources!
This entry was posted on Wednesday, March 23rd, 2011 at 1:51 pm