A battery tester, includes a voltage controlled display. The battery tester is disposed on a battery with a first voltage divider having a terminal coupled to a terminal of the voltage controlled display and a second voltage divider having a terminal coupled to a second terminal of the voltage controlled display. The second voltage divider includes a non-linear device. A major advantage of the tester compared to other testers is that a consumer can merely look at the tester on the battery to determine whether the battery is good or not. This tester eliminates the need to hold the battery and depress a switch to engage the battery tester.