A developed-in charge controller prevents overcharging; charging stops every time a battery is topped off and automatically resumes once the battery is drained. It's advised that you simply charge these batteries each and every 30 times as a way to avoid battery Demise and maintain All round battery overall health. https://hukums.com/products/elephant-12v-electronic-car-tyre-inflator-pump-with-copper-winding-motor-and-aluminium-body-ap-01