The JumpStart Intelligent Fast Charger is a ?smart? charger. It has sophisticated monitoring circuitry that controls the charging process, and it is also capable of ?renewing? batteries by running full controlled discharge-recharge cycles.The charger shows battery voltage and charge status on its digital display. It has four separate charge channels so you can charge one, two three or four batteries AA or AAA at a time ? even on individual charge programs. This allows you to test one battery while charging the others.