I think the words "deep cycle" are widely overused in the battery industry. Some manufacturers of regular starting batt for cars use the term deep cycle. I was in the camping industry for years in both sales and service and the rv batteries we sold with the campers are the same as most marine batteries bought at walmart, napa, autozone. I hot wire is simply ran from your car battery to your trailer plug and then to your 12v "deepcycle" battery in your trailer to keep it charged.Just install a diode switch inside your trailer to stop the draw from your actual car battery when your using your pumps in the trailer. Now true deep cell or cycle battery such as trojan, crown ect. well those are little more expensive and may be better off with a trickle charge, I have never owned one so I dont know.