Fixing a bad cordless battery

I remember reading somewhere that most NiCD batteries fail because the material inside crystallizes from charging cycles. In the article, they said to get a barbeque pushbutton lighter and use it to "recondition" the batteries. I think this was in a Nuts and Volts from last year. Basically, they said to hook the + to one wire and the - to the other and press the button a few times to break up the crystals. I haven't had to try this yet, but since you found replacements, you might give it a shot.

| My Ryobi cordless drill developed a bad battery, and the price of new | replacement batteries is so high that it's usually cheaper to buy | another drill with batteries. I wanted a better solution, but I don't | use cordless drills enough to warrant buying a better more expensive | model. | | So I noticed that at American Science & Surplus they | were selling item #16970, a 7.2 volt 1200mah C-size NiCad battery packs | at $5 each. I bought a couple and took apart my dead Ryobi battery and | replaced the cells. It fit perfectly, I only had to cut & fit a couple | of connections and those I was able to do easily by soldering to the | nickle strips - I never had to solder to the battery itself. I did have | to put about 1/2 amp into the pack for about 5 min to get the voltage up | to the point where the automatic battery charger would take over. | | The installation seems to be sucessful, I'll try to give you more | feedback in a year or 2, after the surplus batteries are long gone & | sold out.
If you have a local shop that sells and services all kinds of batteries, they should be able to replace the cells in your battery pack for a whole lot less than the standard option. We have in my neck of the woods and they do this a lot.

I guess you are talking about one of those piezoelectric ignitors, and I doubt that one would have enough energy to do that job. I have used low voltage power supplies and capacitors to do what you suggest, and you can only resurect the batteries for a short period of time. To do it properly, you really need to open the pack and "zap" each cell individually. If you are going to that much trouble, you might as well replace the cells why you are at it.
The bottom line is that a bad battery is a bad battery. Replace the cells with new, or toss the whole pack.
Vaughn

I just had the same problem and wound up buying a new Ryobi 14.4 drill / flashlight combo for almost exactly the same price as the two batteries alone. So now I have two drills, a flashlight and two good batteries. Since much of time they are being used at my work bench, anyone know how to go about hooking up a 14.4 volt power supply to just run one directly off a plug?
Steve.

Why not just try a 12 volt lead acid car battery, that's 13.2 vdc and is probably close e nough.

Your local hobby shop should have a stock of 1200 - 1400 MAH sub C cells, they are commonally used in electric R/C cars.
Hugh

Better yet, 2300mah AA NMh cells. 4 fit in a space not much bigger than a c. You can usually fit sets of 3. That gives you almost 7 ah of power in the same space!!!!

Ever since they put those recycle your used NiCad battery bins in a few places I never want for replacement cells. When they go bad it's only one cell usually in the pack. You can scrounge quite a few spares from the recycle bins. I sure would like to know how they weld the leads on looks like a spot weld, I guess a short would melt solder.

I make up packs from standard (tabless) cells, using desolder wick as links, and a 140 watt Weller soldering gun. Hit 'em hard and quick..