Speaking of which, it's possible that one of your rechargeables is bad. Do you have a voltage tester?

For the past few years I've had a rash of bad alkaline AAA batteries (I go through a lot). Doesn't matter if they're Energizer or Duracell, it seems that 1 out of every 5 AAA has no charge out of the box, but I don't notice right away. I put 4 in a remote, use it for a couple of weeks just fine, and then it's suddenly giving me a low battery warning. I *know* I just replaced them, so I test each in a battery tester and sure enough ONE of the four is as dead as a doornail with 0 volts, the rest are just a bit lower than full.

This has happened about 8 times or so to me, with different batches of batteries, so it's not just a random fluke...