B+K Precision Battery Capacity Analyzers tests Lead Acid Batteries and displays the batteries stored charge capacity as a percentage and displays both the loaded and un-loaded battery voltage. Models 601 and 602 can also display the battery under tests internal resistance. These units identify batteries, which may be defective or deteriorated. They are perfect tools for testing battery back up systems for emergency lighting, alarm, sprinkler systems, UPS devices and any system using lead acid batteries to provide power.