17-Watt Solar Panel with built-in Battery Tender® 3-step automatic microprocessor controller. 100% portable battery charging and maintenance. Perfect for storage spaces without power access! Once connected, this Battery Tender® Battery Charger will charge and maintain your battery so that it is always ready to go when you are. It's lightweight, fully automatic, easy to use. | Battery Tender ® 17 Watt Solar Charger