Adding and Charging Two 6V Batteries to Trailer Battery Bank for Desert Camping

Question:

I am trying to use the 5th wheel trailer cord connection to charge 2 6 volt golf cart batteries in the back of my pickup while towing a trailer with the ball hitch. I have no 12 volt coming out of the 5th wheel connector. These batteries will be connected to the trailer in tow with #2 battery cables hooked together at the bumper via a fork truck battery connector setup. I need the extra 12V capacity to supply 2 inverters in the trailer, 1-1500W and 1-3000W, while sitting in the desert this winter. The Ford dealer says I blew the trailer module somehow. Is that possible and will my idea for extra 12lV capacity work?

asked by: John P

Expert Reply:

Just to make sure I understand correctly, you have two 6V batteries in the bed of your 2017 Ford F-350 that you will connect to the battery bank on your bumper pull trailer. If you have your 6V batteries connected to your in-bed 7-Way at the same time as your bumper pull trailer (with batteries) then that could very well have blown something on the pickup side of things. You'll want to check with your local Ford dealer about how to get the trailer module changed out or you'll need to run new power wire through a circuit breaker like part # 9510 from vehicle battery back to your 7-Way connector.

To help make sure everything is connected properly you need to also make sure that your two 6V batteries are the same type as the batteries on your trailer and that they are connected in series (see attached) so that they are a 12V system as well. If this is the case then your idea will work as you can always add more batteries to a battery bank provided you have enough room.

Typically you only get a trickle charge out of a straight 12V connection to your batteries. This means that they will have a maintenance charge that basically keeps them from draining when not in use. To make sure that your batteries get the best charge available I recommend installing the Redarc BCDC # 331-BCDC1240D with the Kit # 331-FK60. The BCDC is a unique charger that is able to read what batteries are connected to it and then boost the 12V charge power accordingly. This also has a multi-stage charging system to get your batteries to 100% charge quicker and then you can even tie in solar panels to this system so that you can still get power while boondocking out in the desert.

expert reply by: Jon G