I have rewired my trailer to run the interior lights off the 12v coming from the truck as normal trailers will do when hooked up. Mine ran off a battery under the gooseneck.So I have power from the truck. I saw someone on this forum put a female receptacle on their trailer battery and can plug the trailer basically into itself and have power. Ok, I did that. It works.I just bought the Engager brake away kit with the EASY test button and charger. I have to connect the 12v to the trailers 12v and I'm wondering when I plug the trailer receptacle into the trailer battery if I will be taking power from the brake away kits battery or charging the brake-away battery from the trailer battery.Any suggestion...that is if you can understand what I wrote. :)Thank you.