18V 10W Portable Solar Panel Battery Charger with Cigarette Lighter Plug and Battery charging clip line, for Mobilephone Automobile Motorcycle Outdoor Camping Hiking Fishing Climbing

It requires direct sun to be able to work. Though the panel is inside your car even if it is in direct sun orientation but if your car is cold it won’t charge. The clip wire connection was not weld correctly and it is flimsy. When this clip keep on twisting or moving the wire will definitely break and you have to solder again. Usb sometimes working and sometimes not. I almost return it but realize that it relies on the temperature of the panel to work. If you’ll charge your car battery with this it will take more than a day.