I have had a Ryobi 18 volt rechargeable tool kit for 5 or 6 years now and the batteries simply quit charging. This is the kit you could buy at Home Depot with the drill, small circular saw, flashlight and reciprocating saw. I was about to shell out $40 for a new set of batteries and thought I would check out the 'net for any possiblities of reconditioning. I saw one method that I thought was totally NUTS (but free)....so of course I tried that one first. The poster said to put the battery in a freezer for a couple of days and then recharge it. Run it down, refreeze it and recharge it once again. After the first freeze/charge cycle I did get some response from the battery but I really did not have any hope. The drill ran very slowly for 60 to 90 seconds and stopped. I put it back in the freezer for a couple of days and then back on the charger. The battery was probably on the charger for 3 or 4 days as I had forgotten about it. I saw it today and thought "what the heck". WELL!!! I popped the battery in the drill...pulled the switch and danged if it did not run better than new. You better not hold the chuck end and pull the trigger...it will blister your hand. I put it in the circular saw to see just how quickly it would run the battery down and after 3 minutes of continuous run it was still going strong. Same way with the reciprocating saw. I have no idea the physics behind how/why this worked but as most of us on the SMF are DIY'ers and probably have these types of tools I thought I would share. I did put the batteries in a plastic box for the freeze cycle just in case of rupture. I would cry for months if I ruined my meat supply. As always...your mileage may vary...what works for me may not work for you...but this really did work. I had tried charging the "old fashioned way" a month or so ago with no luck.