Camera indicates low battery even for fully charged battery.

I have connected my PowerShot A2000IS that was doing the same thing for me and I discovered the following:
1) The unit works fine even down to 2.5V providing the supply source (i.e. batteries can deliver 500 mA for a short burst during startup, i.e. when the camera's lens is extended). The camera draws 300mA with screen on after the initial startup current has settled. This means that the camera may not work with batteries like normal alkaline as these don't normally supply large currents, like NI-MH and NI-Cd can.
2) I found that if I lowered the voltage down to (using my bench power supply) that the low power indicator come on at just under 2.5 Vs, BUT once it has indicated low battery, turning the voltage back up to 3V didn't remove the low battery indication.
3) Finally I connected my fully charged (with combined voltage of 2.7V) Ni-Mh rechargeables (old and well used) using wires to allow me to measure their voltage and I found that when I turned on the camera the voltage dipped to 2.3V, but come up after the lens was deployed.

Conclusion and recommendations:
a) Get some new high quality Ni-Mh cells.
b) Don't use Alkaline cells (even Duracell brand might not handle it).
c) Forget Ni-Cd as terminal voltage would be at best 2.6V which doesn