Battery Tester for Home and Workbench Tests 9-volt, D, C, AA, AAA and N Cell Household Batteries. This handy battery tester can be used to test a variety of battery sizes, including the most typical and widely used. The tester reads the amount of voltage remaining to determine how long it will last. Fresh batteries always work best, but if you need to identify how much life remains in rarely used batteries, this simple battery tester will determine if they can, or should, be used as a safe and effective power source.
