Okay, I've run into an unusual problem with my power supply/charger. When I go to charge batteries, I always get an Input Voltage error, because the charger is getting around 19v from the ps, even though the ps is only rated at 13.8v. So, I checked the charger by running it off my van's battery and it worked fine, so the problem seems to be in the ps itself. One thing: I had left the power supply plugged into the outlet (but not turned on) for over a week, if that would make a difference.
Pleaes let me know what's going on!