How To Keep Battery Topped Off When Flat Towing A 2022 Jeep Wrangler JLU

Updated 06/01/2026 | Published 05/22/2026

Products Featured in This Question

Roadmaster Battery Charge Line Kit for Towed Vehicles

(1435)

$52.03

Roadmaster Battery Charge Line Kit for Motorhomes

(152)

$56.90

Question:

I installed a BX8848 Blue Ox LED wiring harness on my 2022 Jeep Wrangler JLU and additionally installed a 12V power supply for my Patriot 3 brake system. After towing the Jeep and then disconnecting it from the coach I had a gotten low battery problem in the Jeep which only cleared up when I ran it for awhile. I never had the problem with a 2018 Jeep JKU which I towed previously with the same Patriot 3 system. Is there a way to wire it so the power for the system comes from the coach to avoid draining the battery. I have a 7 way to 6 way cord from the coach to the Jeep.

asked by: Willy W

Expert Reply:

Hey Willy, thanks for reaching out. Yes, there is a pretty easy way to fix this. All you need to do is wire in a charge line. We have a kit you can use for this, the Roadmaster Battery Charge Line Kit for Towed Vehicles # RM-156-25. This will connect to the 6-way on the front of the Jeep and allow it to charge from the motorhomes battery line, assuming it already has one present (most motorhomes do). That way you can keep the battery topped off without having to start the vehicle every few hours.

I'd say just take a tester and make sure your motorhomes 7-way has an active 12v charge pin. It should, but if not, you can use the Roadmaster Battery Charge Line Kit for Motorhomes # RM-156-75.

Do you usually take your motorhome and JLU on a lot of long-haul trips?

expert reply by: Jesse M

Roadmaster Battery Charge Line Kit for Towed Vehicles
(click to enlarge)

Rolf W.

5/27/2026

The charge line kit worked fine for our 2020 JL Wrangler but we did use a heavier gauge wire than the one that was supplied

Jesse M.

5/27/2026

@RolfW Ah yea that makes sense. Good call! Thanks for sharing!

Richard

5/29/2026

We installed this on our JT and it appears to prevent battery charge loss. We use an NSA towbar with mechanical supplemental braking so the only draw is the LED rear lights...so not much electrical draw. An issue we saw with this kit is the lack of insulation on the terminals, one of which will be hot all the time. We used heat shrink (because that's what we had) to protect the threads / prevent arcing. However, we are considering using rubber thread protectors (we've seen them on sites like Home Depot) instead because they're much easier to install and to remove for maintenance / necessity.

Jesse M.

6/1/2026

@Richard Thanks for the review, Richard! It's great to hear the kit is doing its job and helping keep the battery charged while towing. I also appreciate you pointing out the terminal insulation concern and sharing the heat-shrink solution you came up with. The idea of using rubber thread protectors is a good one too, especially for anyone looking for something that's easier to remove during maintenance. Thanks again for sharing your setup and experience!