Comment Voltages.... (Score 1) 210
Alkaline cells are 1.5v. Neither NiMH or previous generation NiCad cells are that high... NiMH is around 1.2V under load. For some devices this matters. There's one device that I have to coach people on using at work, with NiMH cells, the battery charge indicator always looks half-used which freaks the users out... even though it will work longer at about "half-used" than the original alkaline cells would starting from "full".
Some things don't work at all at the lower voltage.