Battery Load Tester With Automatic Cutoff

A splash screen shows up as we
start that says set voltage to 0 and then press Start for help.

This project is a simple use of an Arduino Nano to make the smarts for a simple but useful test tool.

Here is how a load test is run:

The voltage of the battery under test is shown as BatV.   A cutoff voltage to stop the test is selected with a knob,  About 3.5 volts in this case.

The user presses 'Start' and a power MosFet connects the load to the battery.
While the test runs the runtime minutes,  TMin shows up and battery voltage slowly drops.

The 'Loading' led shows and the 'Running' led blinks as the test progresses.
When the battery voltage drops below cutoff (Cov) for a couple seconds, test stops.
User can come back and see the test has stopped and note the minutes it ran.
Mark-World - Tech Projects To Amuse The Curious
Battery Load Tester

This is a device I had wanted for a great many years and got around to making one.

The Battery Load Tester has two connections to hook up a battery of your choice to be tested and then a load is connected to model your needs for the load you want to test.

In this case a LiIon 81650 high current battery is tested with a 10 ohm resistor.

The tester automatically stops a load test at the knob defined cutoff voltage (Cov).  Stopping the test prevents bringing the battery below its lowest safe discharge level which can and will damage a battery.  Before this tester I had forgot tests and  degraded batteries.  NO MORE!

Several common small battery connectors or connector for a cell phone charging battery are attached in this picture. 

Due to very large currents when I test 12amps and up to 24V this tester has large copper screw terminal connectors.   Not required here but does come in handy to attach most any battery.