has the attached convertor but we are at odds as to how it works. Obviously, when the trailer is plugged into electrical
(as in at a campsite), the convertor gets switched to Transformer and everything is good. Likewise, when the trailer isn't plugged in at a campsite we put it on battery
What we don't fully understand is what to switch it to in order to charge the battery
. Is the battery
charging when we're at a campsite and have the trailer plugged into the site's electrical
? Also, when we're driving and the trailer is plugged into the truck, should the convertor be on battery or on transformer?