Resurrecting a 'defective' NiCad battery
Not sure how useful or already-known this tid-bit o' info is, but it worked for me just now and saved me from having to spend money on a new battery, so I figured I'd share it ... My Craftsman 18v battery was showing as being 'defective' when I put it in the charger, and would not take a charge at all. The 3/8" driver/drill & flashlight set it goes with is a few years old but still in excellent shape, so I had no desire to replace it. It's my 'other' set anyhow ... I use my Makita for the heavy work, and was told that I could not buy any more new toys for a while :-) A replacement battery was looking to cost me at least $50-65 because it's an older model and hard to find for some reason. So, I took a known-good 18v battery, identified the positive & negative leads, MacGyvered that to the 'defective' battery with a couple of lengths of mechanics wire, let it sit for about 10 mins, and voila ... quickly showed on the meter as holding around 15v. Then I slapped it back in the charger and it's humming along like a champ now. No need to replace it!
Not pretty, but it worked and saved me some $$, so that's a victory any day!