Battery Checker Circuit - Capacity Measurement

Close switch after starting! This circuit is a good way to get an accurate measure of battery life by loading it as it would be in a real circuit, batteries have internal resistance which increases as it is discharged which is why measuring a battery open circuit can give false results, this circuit can also be used to measure the capacity of the battery, a worn out battery will have reduced capacity resulting in fast discharge. The circuit consists of a constant current source set by the lower potentiometer and a comparator which lights a LED when the voltage falls below a set point, this is set by the upper potentiometer, this circuit is designed for 5V operation up to 2A but can be adapted for any voltage and current.

published 10 years ago