The project allows you to analyze characteristics of unknown/junk battery especially the capacity and variation of the voltage on discharge. It is controlled with a PC via a serial port. No external power supply is required because it is powered by RS-232C signals. It uses ATmega48 as main controller for dummy load and constant current circuit.
For measurement of battery voltage, four-wire method is used to eliminate an error due to drop out voltage at the wires and contacts.