BatteryBeak: Utility of making internal resistance and state of charge measurements

[Ether]

I believe you are correct that the 3 terminals are hi, lo, and ground. Connect the battery thru your ammeter¹ to two of the terminals and measure amps. Whichever gives you closest to 3 amps is what you want.

You can measure the volts periodically if you wish. Use the manufacturer's published discharge curves as a reference for what the voltage should be² as time progresses. If the battery voltage drops well below where it should be, you can stop the test - the battery is weak. If you're getting good readings and you stop the test too soon, you may get a false result - you may think the battery is OK when in fact it is not.

WEAR SAFETY GLASSES and FOLLOW ALL SAFETY PROCEDURES.


¹ make sure the ammeter is set to 10 amp (or more) scale or you risk burning it up.

² ask if you need help deciphering the curves