Charge Travel Trailer Battery Via the 7-Way RV Connector on a Jeep Grand Cherokee  

Question:

Expert Reply:

You have a couple options available but first, yes, it is possible to provide a trickle charge/maintenance charge to your campers battery from the 7-way RV plug on your Jeep Cherokee and this is done through the number 4 pin that is at the 1:00 position when looking at the vehicle. Please note the attached image. I suggest you first place a voltmeter to the pin to ensure you do not already have a hot pin. If your vehicle has the tow package you should already have voltage present on the number 4 pin.

If you do not have a hot # 4 pin, then you can run a wire to it and then you will need to have a wire on the corresponding pin on the trailer side going to the RV's battery bank. I recommend using 10 gauge wire such as # 10-1-1 to best carry current as a smaller gauge wire will limit potential. Keep in mind that providing a charge current to your battery through the number 4 pin is a great benefit that and relatively easy to accomplish at very low cost. However, this is a trickle charge and will be limited by what the alternator is putting out in meeting the demands of your Jeeps crank/start battery. This will not be reading the voltage of your camper's battery and adjusting charge rate according to its needs. While that is okay, not proficient charging profile, but it works for lead acid batteries. I would not however go this route if your camper's battery bank is Lithium chemistry.

But we do have a rather cost effective product available that does use the energy from your Jeeps electrical system when driving to efficiently charge a battery bank on your RV. I especially recommend this you have a lithium battery bank in your camper. The Redarc In-Vehicle Battery Charger - Single Input, # RED96FR at 12 amps. Or, the dual input, 25 amp version, # 331-BCDC1225D that also works as a solar charge controller. Use this version if you want integrate solar panels.

The Redarc In-Vehicle BCDC Battery Charger - Single Input, # RED96FR will keep your trailer's battery charged using a single-input, DC-to-DC smart charger. This is a multi-stage charging algorithm that ensures a complete charge on campers battery without overcharging it. It has a boost stage that provides a constant charge, then steps down to an absorption charge profile that keeps voltage stable but adjusts the current. This is done to avoid overcharging while bringing battery up to 100-percent state-of-charge. It will then move in to a float stage that maintains charge on the auxiliary battery. This can be used to charge AGM, gel, standard lead acid, calcium, and Lithium ion (LiFePO4) batteries.

expert reply by: Michael R

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7 Way Trailer Connector
(click to enlarge)