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How to Keep Deep Cycle Battery Charged for Winch and Trailer Light Usage


Hi, Im installing a winch and stand alone 12 volt deep cycle battery in my auto trailer. Ideally I want to tap into the 12 volt positive from the 7 pin connector to top off the deep cycle battery while towing, and use the the deep cycle battery to run interior lights and fan when the truck is disconnected from the trailer. My concerns are tapping into the hot from the 7 pin and possibly back feeding into the truck when it is not running 2018 Ram 2500 with factory tow package and grounding. Can I land a ground from the trailer battery straight to the trailer frame, and T into the hot from the 7 pin to power the lights and top of the battery. Is it that simple or am I missing something? Cheers


Expert Reply:

The positive terminal on your deep cycle battery will connect to the 12V circuit from your 2018 Ram 2500 to provide a maintenance charge and you do ground the battery from the negative terminal to your trailer frame.

With that being said, the 12V power from the alternator on your Ram will provide a trickle charge at best (which keeps the battery topped off when not in use) and it won't actually charge the deep cycle battery completely.

Since it sounds like you are looking to use your battery fairly often I highly recommend installing the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1225D for a few reasons. The first is that it uses smart technology to read what kind of battery you are using and then it boosts the power that it is getting from your alternator so that you battery can be fully charged. It also has a built-in isolator so if your Ram still provides power to the 12V pin when the truck is off this will keep your trailer battery from draining your vehicle battery.

One of my favorite features of the BCDC is that you can add a solar panel like part # 34273836 and the charger uses both the power from the solar panel and from your Ram to charge the battery. This is also useful to help keep the battery topped off for when you have your trailer sitting for long periods of time.

expert reply by:
Jon G

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