Abstract: This specification discloses a method and apparatus for testing batteries in which a diagnostic cycle includes a discharge cycle and a charge cycle of five charging pulses and another discharge cycle. The discharge cycle durations are respectively one and twenty seconds. A typical duration for the charge cycle is 80 milliseconds. A plurality of voltages measured during this diagnostic cycle are used to evaluate five arithmetic functions. The results of the evaluation of three of the functions are compared against predetermined limits to determine battery quality. Additionally, the results of the evaluation of the remaining two functions are compared with one another to establish whether or not the battery is defective. This test provides a substantial advantage over prior art tests in that the test is substantially independent of battery temperature and battery size.