I have a Bosh and a Milwaukee 14 volt cordless drills and both are in need of new batteries. My question is can I replace them with 18 volt batteries?

 

No, you can't just put an 18v battery in the drill without smoking it.

 

http://www.primecell.com/pctools.htm

Higher voltage won't hurt a DC motor, but it may zap any circuitry in the tool if it's not designed to take it. That, and most manufacturers have different physical configurations for the different battery voltages, so they can't be mixed.

Jason

 

Thanks guys for the good advice, I agree that it could be hazardous to the drill's health and I don't want to risk killing them, but I could have swore I have seen 18 volt Milwaukee batteries that have the same type of "interface" as my 14 volt one does and the charger appears the same also. I may end up getting some Lithium Bats.

Thanks, Chet

 

I've got a 9.6v dewalt that I regularly run of 14.4 volt and 18 volt bats