So I purchased this driver kit a couple of years ago, but never used the batteries in it. I finally got them out and found one of them showed broken on the charger. I sent it in to Milwaukee and they wouldn't fix it under warranty. I decided to try jumping it with another battery to increase the voltage so the charger would proceed. It worked! It took less than 5 minutes of work. Why couldn't Milwaukee do that and charge a nominal fee? Oh well...