Abstract: Evaluating the condition of a battery typically includes applying a load to the battery for a first time period, measuring a first voltage at the end of the first time period, removing the load from the battery, measuring a first voltage at the end of a first recovery time period after removing the load, measuring a second voltage at the end of a second recovery time period after removing the load, and analyzing the condition of the battery at the end of the second time period. The condition of the battery may be evaluated by using a hand-held electronic battery tester device that evaluates the condition of the battery by calculating the dynamic internal resistance of the battery in a time period of less than one second.