The goal of this article is to give you a practicalunderstanding Lead Acid batteries. We won't address the underlying chemistry, we'll treat them as a black-box and we will discover their characteristics and how to keep them healthy. I'm an amateur. I have absolutely zero relevant background in battery technology or electronics. I just scraped some information together in a hopefully useful manner. The common rule of thumb is that a lead acid battery should not be discharged below 50% of capacity, or ideally not beyond 70% of capacity. This is because lead acid batteries age /. Lead acid batteries can put out so much current that you can use them to weld2. They are widely used in ICE cars to power the starter motor, which needs hundreds of amps at 12 volt to turn.