30-Minute Charge Time Inside the ENERGY STAR® qualified Rapid Optimum Charger a micro-processor communicates with a built-in memory chip in the battery during the charging process, allowing the charger to recognize the battery’s condition and charging history. Through the use of “Active 3 Controls” the charger then selects the optimal charging method according to the battery’s voltage, current, and temperature. The Makita charger also has an exclusive built-in forced-air system that circulates air through the battery during the charging process to lower the temperature, reducing charge time and extending the overall life of the battery. The result? A 30-minute charge time that’s two-times faster than most 18-volt competitors, so the battery spends more time working and less time on the charger.