Rob asks: “I have a Craftsman 18.0V cordless drill. I REALLY like it. Yesterday, Sears had a pack of 19.2V batteries on sale. Can I use these in my drill without hurting it? Yes, they fit, but I don’t want to damage my drill.”
This is a great question. My initial thought is that a 1.2V difference won’t do any short term damage and shouldn’t do any long term damage. There’s some precedence for this in the industry. For example, Milwaukee recommends its new li-ion V18 batteries as “backwards compatible” with their 18V tools, though the V18s are actually 20V batteries. Competitive robot builders often over-volt motors, though they’re willing to trade reliability for performance — something I’m guessing Milwaukee wouldn’t be so hot on.
Charging could be another issue, though if you’re referring to the 19.2V batteries that drive the Craftsman drill/driver we’ve got in the shop here, they’re old Ni-Cds, just like the 18V.
Anyway, I hope you don’t mind, Rob, but I thought I’d kick this out to the readers to see what input they might have. If there’s still a lot of question come next week, we’ll jump on the phone and see what we can find out.