When I first got my house ten years ago, I started buying some Black and Decker Versapak tools because I was needing several cordless tools and it seemed smart to have them all use the same battery. I wound up with a dustbuster, screwdriver, drill, and snakelight. Eventually the NiCad batteries stopped taking a charge and, although B&D had stopped selling Versapak tools, I was able to get two more batteries from Target. That was 2004, but one of the batteries went kaput pretty quickly and had stopped taking a charge at all. Since the dustbuster and drill both need two batteries, I needed something better than these memory-prone NiCad batteries. B&D makes “gold” versions of the batteries that are really NiMH batteries, so I ordered two of those last night. NiMH batteries don’t have memory effect, but I worry that my charger won’t work properly with NiMH (my conclusion was that it would work, but it might take twice as long to charge the batteries).
Today I searched eBay for “Versapak” and found a guy who was selling information for $12.95 on how to rejuvenate Versapak batteries. I’m no dummy, if there is that kind of knowledge available, it is free somewhere on the internet. I did find a site where you would get a transformer and a big resistor and could zap a battery back to life. That seemed complicated.
Then I searched more and learned about chemical “whiskers” that develop in NiCad batteries and cause them to stop charging (or, really, to stop giving off a charge). Searching further about whiskers, I found this page on Instructables. Though the guy uses a welder, basically he is just applying a large DC current to the battery which burns the whiskers out and restores the battery to normal. All he did was touch the ends to the battery. It gives off sparks and the battery is revived.
I don’t have a welder, but I do have a car battery which has a lot of amperage. I put on some gloves and got my jumper cables. The + end of the Versapak battery is inside a hole on one end of the battery and the outside of the battery is negative. I found a bolt that would fit in the + hole and held the bolt in the jaws of the jumper cables. Then I put the – jumper clamp around the battery itself. Wearing gloves to keep myself from getting shocked, I stuck the bolt in the hole and got a few small sparks. I did it again for just a second or so. Is that all there was to it?
Yes. I took the battery back inside and hooked it up to my volt meter. Before the battery was giving off 0.01 mV. Now it was up to 4 V, just like the fully charged good one. I stuck it in my screwdriver. Power!
Amazing. However, the power didn’t really last long. I am recharging the battery in its charger to see if I can get something closer to a full charge.