Battery capacity tester

[electron_misfire]

Hi all,

I'm working on a project to test different batteries and their capacities.
I was thinking of just doing a simple circuit consisting of a resistor and a switch.
My concern is basically that it's just too simple. Does anyone have any improvements? Any tips or suggestions?
Oh and I already know if battery data sheets, I want to do it myself.

Thanks

[Artlav]

Not much complexity required - battery, load, N_fet for low voltage cut-off, AVR or arduino's ADC to log data.

Watch out for connections - a little contact resistance can go a long way at skewing up the results.
Quality breadboards are adequate to get 5% accuracy, but a proper PCB would be more precise and require less maintenance.

Chinese battery sockets look almost the same as good ones, but good ones give consistent contact resistance, while chinese ones give random ones.

Beware of chargers (NiMH related), they can charge to various levels each time, instead of full: https://www.eevblog.com/forum/projects/battery-capacity-measurement-gives-wildly-varied-results/