I forgot to mention earlier that some UEI remotes have low battery detect logic. Common rechargeable batteries are Nicads. Nicads are very tricky to do low battery detect on. A device designed for low battery detect on non rechargeable alkaline batteries has no hope of getting the low battery detect even close for Nicad (most often and most annoying it reports low batteries as soon as even a small fraction of the full charge has been used, so you get a low battery warning almost all the time). Even a device designed for Nicad batteries has a hard time doing decent low battery detect.

Rechargeable alkalines have very similar low battery characteristics to non rechargeable alkalines, so typical low battery detect logic will work OK. Rechargeable alkalines are also practical and economical to use in a remote.

NiMH batteries have complex low battery detect issues, different from either alkaline or Nicad. I don't know how consumer NiMH batteries affect the low battery detect in a 15-2116. I guess from DLF's experience it must not report low battery too early by much (or DLF would have noticed). If it reports low battery too late, that may be a non issue since you might be in the habit of recharging before the low battery report anyway. (I don't know if Mike is even planning to use them in a remote with low battery detect).