I’ve got several cordless drills. 1- 7.6v, 3-12v, 2-18v. Also one 18v skil-saw. Probably, in fact surely, a couple of other old dogs in there. Major drillers these days are “Mastercraft” branded versions of Ryobi tools. Most all have One-hour chargers.
The last 18v drill I bought was pretty much the same 18v as before but with a THREE-HOUR charger. Decided to keep it as I have so many good batteries and chargers.
This is the question….Why do good, (one hour)batteries have three terminals. The three hour batteries have but two. They look identical except for this factor. When the 3-hour batteries are inserted in the one-hour charger, the “charged” light allumes, preventing charging.
What does that third terminal do?
Can I some how charge my 3-hour batteries in my 1-hour charger??
Replies
Most likely they are used to measure the temperature of the battery.
Controlling batter temp is the single most important thing that can be done to extend battery life.
So you can have a very simple trickle charger that takes hours (6-12).
A programed ramp charger that takes a couple of hours.
Or a use a "smart" charger that can force as much current as the battery will take without overheating (less than an hour).
There are several other ways that 3rd terminal might be used, but most likely it is for measuring temp.
Thanks for replying, Bill. Do you think the batts. could be retroed to work in the 1-hour charger?Alan Jones
You might find that some of the battery rebuilders have done this. You have the problem of not only getting the appropirate temp sensor (probably no problem once you find out what is being used from one of the 1 hr battery packs)
But you also need to add the contact to the battery pack and that is probably a more dificult problem.
You can try a google on "rebuilt nicad battery packs" and similar.
Thanks again. I'll let you know what I find out.Alan Jones