Some batteries do indeed have a tester,
www.youtube.com/watch?v=k6Gz5Gom5NI
As they are a thermal process they probably use a fair ( or unfair ) amount of energy which might shorten the battery life a little bit.
www.youtube.com/watch?v=k6Gz5Gom5NI
As they are a thermal process they probably use a fair ( or unfair ) amount of energy which might shorten the battery life a little bit.