The Ryobi RC18120 ONE+ Compact Fast Charger charges at a rate of 20Amph meaning you can charge a 20Ah battery in 1 hour It is compatible with all ONE+ 18V Lithium-ion batteries Indicator lights show the status as batteries are charged and maintained Intelligent condition monitoring evaluates the batterys voltage and temperature while charging ensuring long-term durability Ready-to-go indicator shows when the battery has reached 80 capacity