Daniel Prince wrote:
Sometime ago, I bought a used camera on eBay. It uses two AA cells.
I noticed that I was not getting very good battery life with Kodak
2.1 ah pre-charged cells.

Yesterday when the camera said that it needed new batteries, I
checked the voltage of the cells. One was 1.288 volts and the other
was 1.292 volts.

As someone else pointed out, you need to test the batteries under load.

Buy the battery tester at

"http://www.nimhbattery.com/zts-mbt-1-battery-tester.htm" or
"http://www.thomasdistributing.com/zts-mini-mbt-battery-tester.htm"

which will do a pulsed load test on your batteries. Of course the cost
of such a tester would buy a lot of new batteries.

You can see a graph of battery capacity versus voltage on the battery
data web site, at "http://nordicgroup.us/battery/nimhdischgrid.gif" but
it's for four 2700 mAH batteries, so adjust accordingly. Basically, once
the voltage falls below 1.2V, the remaining capacity falls very rapidly.

The flat discharge curve of NiMH batteries is both a blessing and a
curse. The problem is that it's extremely difficult to have an accurate
battery fuel gauge for NiMH cells because the voltage falls by such a
small amount for most of the capacity.