Dave,
As a woodworker, I think I'm up to 6 drills, four of them cordless.
I feel your pain! My first cordless drill was a 14.4V Craftsman that I paid $99 for a drill and two batteries, only to find the replacement batteries were $50 each!
What I've done is:
- when the battery dies, I send it off to a fellow who runs a small shop (in PA) I think. He rebuilds them for a very reasonable price. I he uses good cells; I've been very happy with the quality of his work.
Then to prolong the life, I've researched the rules/tips from a variety of mfgs and do the following
- I do NOT run my NiCads down completely anymore. This was the hardest one to get agreement on. And its may differ for Lithium ones, but in any event, as soon as I hear the drill dragging, I switch to a fresh battery
- I do NOT leave batteries on their charges (even the smart chargers). I charge them, then pull them off
- When charging I set a simple dial timer to the specific charge time. My Milwaukee's want about 90 mins, my Bosch batteries want longer
- The dial timer cuts AC power have the desired time, then I come back in the morning or whenever and pull the batteries off the charger and store them in a cool spot
I've been able to eek a few months out of a dead battery using the Freezer trick.
I've never tried the high-voltage shock trick.
I'd be interested in hearing from others on tips and techniques they do to prolong the life.