Wagan Solar ePanel Charger for 12 V Battery converts daylight into electricity to charge 12 volt batteries, extending battery life. This power supply is ideal for batteries stored in caravans, boats and vehicles in long-term storage and is suitable for trickle charging a wide range of batteries and power packs. It can also be used to charge laptop computers, cell phones and other DC powered items. This power supply requires only daylight (not direct sunlight) and is ideal for indoor and outdoor use. The Solar Panel is made of high efficiency mono-crystalline solar cells embedded in transparent vinyl acetate behind tempered glass with heavy back sheet ensuring maintenance free performance. Specs: Peak Wattage (Pm): 12W, Peak Voltage (Vmp): 15V, Peak Currency (Imp): 0.77A, Open Circuit Voltage (Voc): 18.8V, Short Circuit Currency (Isc): 0.87A.