Recommendation for Wiring Breakaway and Marine Battery on Enclosed Trailer

Question:

I have a enclosed box trailer with a marine battery to run lights and such charged by the tow vehicle. The charging/power source is the same for both. If I install the breakaway kit with the additional battery, how does that prevent drainage of the breakaway battery in the event that the trailer battery is overused?

asked by: Jeff C

Expert Reply:

For your enclosed box trailer, it is best to let the breakaway battery run the breakaway system and use the accessory battery to power your trailer's interior lights (or other parts). This is the best option because your breakaway battery needs to be completely charged at all times and it's possible that the interior lights can drain the battery of the trailer.

As you mentioned in your question, when charging two batteries on the same circuit, there is the potential for draining both. A solution for this is to simply install a diode like # RM-690 to prevent this from happening. The diode will only allow power to flow to the battery and not from the batteries back to the 7-Way (or each other). I have attached an image that shows how this will be done.

expert reply by: Chris R