Power meter for low power (equipment advice)

[micro571]

I'm looking for a power meter for doing power measurements of a low power device. Voltage is 3.7V and the current expected will be in the range of 0.5 mA - 60 mA.

I'm looking for a device that will tell me the WHrs as they accumulate.

I've seen power meters for measuring radio-controlled models, but those are meant for measuring many amps.

Any suggestions?

 

[RadioRon]

Watt-Hour meters used for mains measurement are special because they correct for power factor and distortion. If your measurement is of a resistive load where current and voltage are sinusoidal and roughly in phase, then a simple logging Ammeter is all you need and the results can be multiplied by the constant voltage after the fact. One tidy way to do this is to get an inexpensive data acquisition card with a USB port and use your PC. You would have to interface the DAQ to your circuit in a way that allows isolation (probably) but otherwise this is simple measurement of voltage across a precision sense resistor.