Makita 18 V Lithium-Ion batteries resist self-discharge so they're ready for use even after long periods of storage. The Makita rapid optimum charger is a smart-charging system that communicates with the battery during the charging process to monitor current, voltage and temperature. This advanced charging technology helps optimize battery life and deliver a faster charge. In addition, the charger has a built-in fan to cool the battery for faster and more efficient charging, even in hot weather conditions.