CTEK (40-186) D250SA 5 Step Charger - 12V - 20 Automatically selects best and most efficient source of up to 2 that are connected to the charger for charging battery Fully automatic 5 step charger adjusts the charging voltage and current according to the state of charge and temperature of battery Great for "off the grid" applications with its multi-step charging from alternators and solar panels Can be connected directly to solar panels without the need for a regulator