I always try to have fully charged batteries before leaving for a camping trip. It does take battery power to raise and lower(unlock safety bar). I always carry jumper cables to jump from the truck battery to the trailer battery (if the trailer battery goes dead. Towing, I run the refrigerator on 12 volts. Check this forum for charging battery while towing. I had to upgrade my system. Also, I leave the trailer pluged in to 110 volts until I see the whites of my wifes eyes (she has gotten delayed at work before and my battery almost went dead).
Congrats on the trailer, your adventure has just begun!!! If you have questions, we are here to help fellow Hi-lo-er's. Many of us have done mods to are trailers, it's either we have some form of OCD or we (like me) are banned from making any more holes in the sheetrock in our home after the remodel.
2006 22ft towlite (replaces 97 21TL)
2006 Toyota tacoma pre-runner 4.0 L V-6 quad cab
w/ 98 chevy Powervision towing mirrors