www.amazon.com Wagan 2017 Solar Car Battery Charger. Wagan Solar Car Battery Charger is the easy, maintenance-free way to keep your car battery charged and ready to use whenever you need it. If you don’t regularly use your car, the battery slowly discharges to the point where the engine won’t start. To prevent this situation, simply plug this item into your car’s 12 volt DC cigarette lighter socket and leave the solar panel on the dashboard or where it can absorb direct light. The solar cells will automatically charge your battery even on cloudy, overcast days. LED blinks to indicate the charge and the solar panel is made of high-efficiency mono-crystalline cells embedded in transparent vinyl acetate behind tempered glass. The device is waterproof, scratch and UV resistant. This is an excellent battery maintainer that will keep the battery topped off when the vehicle is not in use. It constantly replenishes your vehicle by sending a maintenance-level charge to the battery of your vehicle and uses male alligator clips as well. Lighter adapter requires a lighter socket/power port that works with the key out of the vehicle. With the solar car battery charger, not only are you keeping your battery running efficiently, but you can do so with clean energy directly from the sun.