Right size resistor

[JimmerG]

So I understand that to correctly measure a battery's charge (Volts) you need to stick a resistor across the terminals (briefly) whilst checking with a DMM.

I'll be checking 2500mah protected 18650s, and I've got a 10ohm 3 watt resistor - should this do the job?

Will this also work with Nimh AA's?

Thanks for your help.

 

[Mr Happy]

The use of a resistor to provide a small load is mainly applicable to primary CR123A cells and alkaline cells.

With a lithium ion cell like an 18650 you can just measure the voltage directly. No resistor is required.

 

[lctorana]

...I've got a 10ohm 3 watt resistor - should this do the job?

10 ohms will be fine. Observe the no-load voltage, and then see how far it drops with your ~0.4A load.

Will this also work with Nimh AA's?

Yes. You can also use a 1.2V bulb.