On Tuesday, August 27, 2013 11:00:26 AM UTC-4, wrote:



Both to some extent but sitting idle, either on the charger or off, is
tough on batteries (particularly Ni-Cads). That is why cordless drills
get such a bad rep from homeowners and contractors seem to be fine
with them.

New battery technology has help tremendously. Unfortunately, the base cordless dremel is still NiCad. You have to spend more to get the lithium-ion batteries.

Problem with nicads is that they lose charge just sitting, so when you want to use it, you have to charge it. If you leave it on the charger (most cheap chargers, like the dremel's) it cooks the nicads. You can get a cheap AC timer and set it to turn on 1 hour a day. Plug the charger into it, and the battery will stay topped off and ready to go without overcharging.