20 Watts 12 Volts Polycrystalline Solar Panel Module Battery Charging RV Boat High- efficiency silicon solar cells ensure high performance of solar modules and create maximum power output. 25-year transferable power output warranty: 5-year/95% efficiency rate, 10-year/90% efficiency rate, 25-year/80% efficiency rate. Small in size and easy to take. Perfect for 12-volt battery charging or multiple panels can be wired in series for 24-volt battery charging or for grid-tied applications. High transmittance low iron tempered glass with enhanced stiffness and impact resistance. Outstanding electrical performance under high temperature and low irradiance conditons. Corrosion-resistant aluminum frame for extended outdoor use, allowing the solar panel to last for decades as well as withstand high winds (2400Pa) and snow loads (5400Pa).