Protect your battery life with this 3 stage charger from Minn Kota. Improperly charged batteries will develop a "Memory" that will permanently reduce power capacity. Minn Kota 3 stage technology feeds power in rapidly at first in the "bulk" stage. As the battery reaches capacity, the charger goes into "absorption" mode which tops off the charge. The "Maintenance" stage allows you to keep a battery charged for an extended period of time: whenever the battery weakens slightly, the charger tops it off. *Not for use with lithium-ion batteries.