A Designed-in charge controller helps prevent overcharging; charging stops whenever a battery is topped off and automatically resumes when the battery is drained. Just Remember that using a 2-amp battery charger, it can easily take a complete day or two for it to recharge an individual battery. Don't just that, https://hukums.com/products/xtra-power-angle-grinder-xpt-407-disc-dia-125mm-speed-11800-rpm