You would have to have a seriously tiny battery to get "cooked" by that panel, 18V at 100 watts is 5.5A. Any substantially RV usable 12V battery would laugh at getting 5.5A charge for the absolute max of 4-5 peak charging hrs you would get per day.
But to get that 18V you must use the "port" on that panel which looks like a small "barrel" connector (take a good look at the cable and universal connectors in the pictures).. That "port' most likely accounts for one of the three "outlets" and most likely has two 5V USB outlets..
That advertiser mentions plugging in laptops to it, I personally would not trust plugging any laptop into a unregulated solar panel unless you really want to take a chance that it won't go up in smoke in full sunlight..
It must have some sort of voltage regulation in order to allow one to plug a laptop into it.. Not all laptops accept 18V, some are 17V, some are 18V, some are 18.5V, some are 19.5V.. That is the reason for all of those little adapter plugs, those plugs tell the regulator what to set the voltage to..
But for your purpose, even if that panel offers 18V (standard for most "12V" panels) it is going to be 5A or less which unless you have it hooked to a small motorcycle battery, most likely won't harm your RV battery unless you leave it hooked up for months at a time.. Battery of 200 Ahr or greater, 5A for a few hrs per day is a bit above trickle charging..
But personally, that is one horribly expensive panel for the small amount of wattage..
