charging batteries

[snowball]

when I talked with the mobile teck about the generator he reminded me that I could
plug the trailer into the truck and charge up the batteries (the sun has been clouded over and although it charges not as full as it typically will get with the panels) I forgot to ask if the truck needs to be on assume so but have learned never to assume... so does anyone know would appreciate knowing what to do
sheila

[Bethers]

Yes, the truck needs to be running.

[snowball]

thanks Beth