How can undercharging harm my Discover battery?

In many respects, undercharging is as harmful as overcharging. Keeping a battery undercharged or continually undercharging allows the positive grids to corrode, lead sulphate to build up, and plates to shed, which can dramatically shorten life. Also, an undercharged battery must work harder than a fully charged battery, which contributes to shortened life as well. A constantly undercharged battery has a significantly reduced capacity because of the effects of acid stratification. It will easily be inadvertently over-discharged and eventually damaged.