Li-Ion battery capacity tester

[microbug]

I just wanted to share my quick Lithium-Ion battery capacity tester. It's based on an Arduino Mega (although the Uno or pretty much any other MCU could be used), and discharges the battery through a 4-ohm load for approximately 1A of current. I've attached the Arduino sketch as a .txt file as the .ino filetype isn't on the forum whitelist.

Yes, I know it's yet another Arduino project / whatever, but I spent some time on it and the info might be useful to someone in order to save them the effort .

I'm testing 18650 batteries which I pulled from old laptop batteries.

EDIT: I didn't bother with a schematic, but the hardware side is as follows: the battery is connected through a 4-ohm 7W load to the N-channel enhancement-mode MOSFET's drain. The source is connected to the battery's negative terminal and to ground. There's a 47k resistor across the gate and source pins and a voltage sense wire coming from the point the battery's wire gets to the breadboard.

[void_error]

You can use a constant current sink to discharge the batteries. There's an EEVblog video on that.

[microbug]

Yes, but I can't be bothered with a heatsink etc. this does the trick!