It will be a discharge of a battery of solar panels at night without special equipment?
I am interested in buying a 5-watt solar panel for connection Cars to a battery.
You can get one with a diode. This will stop the discharge. Why do you want to charge the battery with a panel solar? You may charge only the battery and make it wear out sooner. It's best to leave the car to charge the alternator for you. Unless, of course, has other electrical items connected to drain the battery.
DIY CHEAPEST Solar Panel System Ever Part 2