I got the same problem when my sanyo batteries exhibit low charge on the camera batt indicator, sent an email to eastgear and got this reply
"Hello
NiMH rechargeable batteries are typically rated at 1.2v whereas
alkaline and lithium are rated at 1.5v. Thus you have a total voltage of 7.2v
versus 9v when using alkaline or lithium. While rechargeable batteries
start at a lower voltage, they are able to maintain this voltage for
longer than alkalines which have a linear discharge curve.
The lower voltage also means the battery indicator will show the
batteries are at partial instead of full power. One way to test would be to
compare the number of shots you can take with alkaline versus NiMH
rechargeables. The NiMH should be able to take more despite being at partial
power.
Using AA batteries in the BG-E3 is usually meant only as an emergency
measure.
Regards
(name)"
