Understanding battery capacity NiMH

[ku637]

Hi ,

I would like to understand the curve given in an NiMH battery and calculate available energy from the battery for my circuit usage.

Attached is the snap shot of a discharge curve for a 500mAh NiMH button cell battery.

I want to calculate the available energy for discharge current close to 3C ( i..e.1500mA)

The curve says the battery reaches cutoff voltage at 425mAH.

So can i take simply 425mAh x 1.4V ( full charge voltage)=‭595‬Wh as energy available or is it that i need to take the difference for energy levels at two different voltage levels

i.e calculate the energy at 1.4V as E1 and calculate energy at 0.9V as E2 and find the available energy as difference between them E1-E2.

If its the latter case , if any body can show me how to calculate that will be helpful (I'm confused about if i can multiply same mAH i.e 500mAH for both E1 @1.4V and E2@0.9V calculation)

 

[Easy peasy]

easy, 350mA-hr if you go down to 1.05V - the ave volts are approx 1.1 so the watt-hours are 385 milli-watt-hours, or 100mW for 3.85 hrs ... for example ...

 

[Audioguru]

Instead of overloading the tiny battery you should select a larger battery that can produce the amount of power and duration that is needed.