Yeah, having a (mostly) dead Battery every time you go to use your Cordless Tools drive me nuts
I have a nice set of Craftsman, C3, (19.2V) Cordless Tools, and the bleep Batteries (3 of them) were NEVER charged when I needed to use the Tool(s)
So now, I keep one plugged-into the Charger at all times
Every time I go into the shop, I switch-out one, and this does seem to keep them all (mostly) charged
Also, I use the "Flashlight Tool" to fully drain, then re-charge each Battery once the given project is done