Somewhere I came across an article on the Internet about reviving NiCd batteries (nickel cadmium) that no longer hold a charge. The method is to "jolt" them by applying a voltage equal to or a little greater than the battery rating. The current is to be 1-amp for 30-seconds. This dissipates a kind of chemical cobweb in the battery that forms over time, especially when the battery is used infrequently, shorting it out. After the jolting the battery is to be charged normally.
I have a 5-year-old 18-volt drill that came with two standard NiCd batteries. They worked well for about 3-years and then began less faithfully holding a charge, eventually becoming useless. 2-years ago A replacement NiCd battery was about $60. This annoyed me because I originally paid $80 for the drill kit and could go buy another for about the same price. What a waste of a good drill to trash it because of the price of batteries, so I procrastinated. Today there is no replacement battery available for the drill, but I could rebuild the battery using individual sub-C high capacity NiMh (nickel metal hydride) batteries for about $65. A few days ago as a last resort I tried the jolt method on the dead batteries. It worked! It did, however, take four charge/discharge cycles for the batteries to reach full capacity. For a Power supply I used my home's doorbell power supply transformer (estimated 1-amp capacity, transformers are current self-limiting),a full wave bridge rectifier, and 4-jumper leads. A talking volt meter was used to make sure that I got polarity correct. Caution: Current must be limited in amount and duration. Too much could cause overheating or worse, an explosion. - Gil Laster, Charlotte, NC [Non-text portions of this message have been removed]
