I have inherited a set of Dewalt 18v cordless tools -- 2 batteries (pretty sure they're lithium DC9096, 18v XRP), charger, two drills, flashlight, impact driver, cutoff saw. I've avoided cordless ever since a Craftsman drill I had several years ago died from inactivity. I just don't use cordless often enough.
What, if anything can I do to keep these batteries usable? I wasn't sure of the charge when I got them, so I charged each of the batteries and they are now on a shelf, off the charger. The Craftsman was NiCad.