ECO-WORTHY 10W Solar Car Battery Charger Maintainer 12V Waterproof Solar Panel Portable Solar Trickle Charger for Car Truck Boat Lawn Mower RV Trailer Tractor ATV Utility Vehicle BatteryFunctionSuitable for keeping vehicles boat battery charged during the weeks unused. No need to disconnect the battery or have someone start the vehicle periodically. The indicator light on the back can observe the charging state. And its waterproof, you can safely use it outdoors(After experimental test) ProtectionThe 10w monocrystalline solar panel uses trickle charging to charge the battery without causing overcharging. Built in blocking diode