Need some advice from someone with a bit of electrical knowledge. I have a Craftsman 16.8 volt drill with a dead battery pack. Sears wants $60 to replace it. I notice in their stores several much cheaper packs but of a different voltage. They all seem to have the same physical plug-in shapes. What happens if I put a 19 volt pack in my 16.8 drill? Will I burn up the drill? How about the charger? What happens if I put a 19 volt pack in a 16.8 charger? Does it then only charge to 16.8, thus becoming OK for the drill? Help appreciated.

A better solution would be to have your battery pack rebuilt. I have send a number of rechargeable batteries to: http://primecell.com/index.html They come back even stronger than they where originally and at a reasonable price. I would never purchased another new battery pack again. I am sure that there are other places that will rebuild your batteries but I mention Primecell because I have had a great experience with them.

Good suggestion. In many areas there are Batteries Plus or Interstate All Battery Centers that can do it.

A little experience I have is that the connectors might look alike but on closer inspection there are variations on the connector shape. I know the 18V battery won’t fit an 19.2V charger. Don’t know about the other voltages but I’d assume they change the shape of the connector so a wrong battery won’t be connected to the wrong charger.

No, it is not OK. There’s more to it than capacity. There’s also the rate of charging. A mismatch between battery, recharger and tool risks overheating the recharger, the tool, or a battery explosion. The manufacturers do this on purpose – change up their batteries so when the battery or the recharger dies, you have to buy a new drill. This the reason I specified “Corded drill” when I put that item on my Christmas Wish List. I received a battery powered drill. I used it for years until the battery charger died. Then I went out and bought myself a corded drill like I wanted in the first place. Bonus: choosing my own meant I could try them out and got a drill that was not too big (read: fatiguing to use) for my small lady-size hand. I just don’t need to use my drill in places where my long orange extension cord can’t reach. The house is only 42 feet long!