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Kit allows up to 15 amps from your RV's battery to be used to maintain the charge of your towed car's battery while the car is being towed. Charge line connects to the 6-way or 7-way plug on your vehicle. Requires separate charge line in RV.
Features:
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hey everybody. Ryan here at etrailer. Today, on our 2022 Chevy Equinox, we're gonna be showing you how to install the Roadmaster battery charge line kit for towed vehicles. But before we do that, why don't we check this out and kind of go over why it's a good idea to use one of these. When it comes to setting up a flat tow, oftentimes, there's a handful of small components that are often kind of overlooked or forgotten about that you can use to make everything more complete, make your life a little bit easier, and have things set up the right way. And a battery charge line kit is one of those components.
And matter of fact, this is something that I don't only recommend for the Equinox, but just about every flat tow that I do, I always recommend one. And what this is gonna do is essentially trickle charge or maintain your vehicle's battery whenever you're flat towing it. And a lot of times, you can run your battery low because the vehicle's supplemental breaking system uses the battery power. And so, what can happen is, you know, you're over the road, six, eight, 10 plus hours. Over time, constantly just stealing a little bit of juice from the battery, it can wear this down and make it flat.
And so, you'll get to where you're going, try to disconnect, try to start the car, and it's dead, and then it's a big pain. You gotta deal with charging it, getting the jump box and your cables out, and everything else. So, having this charge line is gonna prevent all that. It's gonna keep your battery topped off and ready to use whenever you go to start the vehicle. Not to mention too, on newer cars nowadays, a lot of things are electronically controlled.
A lot of times, you'll have electric assist steering, electric assist brakes, and everything's computer controlled in a sense. And so, maintaining proper voltage is essential for a lot of those things to work. And with a dead battery, obviously, that's not gonna happen. So, a charge line will keep all that stuff kind of go into, I'm not sure if the Equinox uses all that type of stuff but just generally speaking. And another thing that this can help prevent is premature failure of your battery.
So, a battery will have so many cycles it can go through. So, if you drain this thing down and then fill it up, and drain it down and fill it up, drain it down, fill it up, that's going to decrease the overall life expectancy of it. So essentially, trickle charging this and keeping it topped off the whole time should really extend the life of the battery and keep it in good working condition. The way the kit is gonna work is really simple. It's gonna use some of your motorhome's auxiliary power coming out of the seven-way. That current's gonna flow up through here through a breaker. And this is just a circuit breaker. It's gonna protect everything in case there's a short or something along them lines. And then that current's gonna flow through the wire to your positive battery terminal. Now, you are going to have to have your car battery needs to be in good working condition. This isn't going to bring your battery back to life if it's already dead, or has a bad cell, or something along them lines. And it's not going to affect your motorhome's batteries either because your motorhome has its own charging system. It uses an alternator and there's extra amperage that is sent back to the seven-way that we can use. So, it's not gonna harm anything there or create any issues as far as that goes. Other than that though, at the end of the day, a small but really important component. This could really save you a lot of hassle in the long run. As far as getting it installed, it's really not bad. Essentially, it's two wires and really shouldn't run into too many issues. So, as long as you take the time, it really shouldn't give you any trouble. But speaking of that, why don't we go ahead and hook this stuff together now. To begin the installation for our charge line, we're gonna be here at the front of our vehicle. And clearly, we have the front fascia taken apart. That's because we're doing all this at the same time that we installed our base plate, which is what I recommend doing. We have all this extra room to work. I also suggest doing this the same time that you're doing your diode wiring because this is gonna route in a similar matter, a similar way. And you'll already be in the back of the connector plug here, so just save you a little bit of time. But with that said, you wanna take your charge line wire here, the red wire. Bring it down to where our connector plug is. You'll strip back the insulation a little bit. Something like that. Give those wires a good twist. And we're gonna hook this up to the center post on the back of our six-way connector. So, you just back out that set screw a little bit. Take the wire and carefully place it into the terminal there and then just tighten the set screw back down. Now, that we're hooked up, we can take our rubber boot, put it back over our six-way connector. And you can apply dielectric grease, and sealer, and stuff to the terminals inside there, and tape everything up and keep moisture out. I like to wait till the very end of a flat tow setup though to do that just so we can make sure everything's working and stuff. That way, If it's not, it's not a big mess in here. But for now, we'll go ahead and just mount this up to our base plate. And then the wiring is gonna get routed inside of the engine compartment. So, just ran it along through here and up where it comes in. Essentially, right underneath our headlight. So, here's where our charger and wire comes up in engine compartment. And this is gonna get routed to our breaker, which I have mounted right here. So, I just remove this nut using a 10 millimeter socket, put this over it, and tighten it down. So, these screws, or the nuts rather, on the breaker, go ahead and take those off. Careful with these. They're easy to drop and hard to find. So, we'll get them off. Then we're gonna take our wire and cut it to length. So, we'll go about right here. Cut that. Strip back the insulation. Take a small ring terminal then crimp that on. And then this is gonna go over the gold post. It's gonna be labeled battery, so you might be tempted to hook this up the other way, but since the motorhome is essentially acting as our battery, this is how we do it. We'll reinstall the nut. Come back with the a 3/8 socket and then snug it down. Then for our other wire here, we're gonna strip back both ends. One end we're gonna crimp on a small ring terminal and the other end is going to receive a large ring terminal. Get them connected. The small end will go over the silver post there. Get that tightened down. Once that's snug, this is gonna go over to our positive battery terminal. So, we should be able to pry this up. Let's see if I can get this whole piece off. Make it a little easier. And we will be connecting this to the positive terminal there. I'll take this off using a 10 millimeter. And a lot of times, these aren't designed to come completely off, at least very easily. And if that's the case, not a big deal. We have a way around it. Loosen this up and this is one of those. So, I'll show you what we're gonna do here. We'll loosen this up quite a bit. About like that. And then we'll take our ring terminal and you're gonna cut a small opening in it. And then with this being a little bigger, what I like to do is kind of pinch the ends closed again and then recut it out. It just kind of gets a better bite around it, I feel like. And we're just gonna slide this in like that. And then I'll just tighten the nut back down. Once this is tight, that's really all there is to it. And that'll finish up our look at and our installation of the Roadmaster battery charge line kit for towed vehicles on our 2022 Chevrolet Equinox..
Customer Satisfaction Score:
96% were satisfied with this product
4% of customers were not satisfied
Ratings & Reviews
My installer, from you guys, did a GGreat job, no issues!
I had this professionally installed and it didn’t work the way I thought it should. When my tow vehicle was hooked up to my RV and the RV wasn’t running the Tow vehicles battery would feed back into the RV and the radio, back up camera, and GPS would remain on in the RV. This would ultimately drain the tow vehicle’s battery. I ended up replacing this with an RVi unit.
Everything was there for an easy instal lation
Everything has been very reliable.
Great product from a very reputable company. Easy to follow instructions!
Easy to install and a must have to keep your battery charged on your towed vehicle.
Exactly what was needed for keeping my battery charged while towing our jeep. Great price and happy with the result.
Excellent customer service provided all parts as described.
Easy install. Especially when installing in conjunction with the towed vehicle wiring kit. This will keep your battery charged due to battery drain from the turn signal/brake/tail lights on your towed vehicle.
Everything fit and works well. I’m happy with the etrailer instructions I installed everything myself didn’t take long at all
Really simple install if you dont drop a screw into the engine compartment…lol. Could use a little extra wire, maybe 12 inches to account for ‘things’
Solid option for a charging solution while towing. Easy DIY install.
Works great, I was having trouble keeping my car battery charged while flat towing. I have to keep my car key in the acc position and its electronics and the power brake has to get plugged in the car lighter eating away at my battery so when I stop usually around the second stop and restart the car the battery is dead. With this charge line kit my battery stays charged! It’s a win. I hope I explained it properly
I never knew I needed this for flat towing. Sales rep helped me pick the right item. Shipping was in a timely manner and the price was fair.
Ron
12/20/2025
The Roadmaster accessories work great - the brake switch in the car is ideal for turning it on and off as required.
Works as promised and has kept the battery charged
have successfully completed the installation of the following items that I purchased from etrailer:
> Nighthawk RM-676 tow bar
> RM-524458-5 base plate
> DEMCO Stay in play DM86VR
> RM-152 diode wiring kit
> RM-156-25 charge wire kit
> RM-88400 brake switch relay kit
I work slow but methodically. I had no issues other than the high degree of difficulty for a 68 y/o man working alone. This project exceeds the abilities of someone NOT mechanically inclined. There is also the need for some specialty tools. I found that feeding the wiring through the dash, firewall, and underbody was more difficult than installing the front baseplate. Overall, I am satisfied with the function of this installation. I am glad I did it myself rather than having it done.
Tow vehicle: 2021 Entegra Emblem 36U
Towed vehicle: 2018 Ford Fusion Platinum Energi
Jeffrey
11/19/2022
I have no regrets with this purchase. Items preform as advertised with no issues. I am very satisfied with Roadmaster and Demco products.
I ordered all the parts required to safely flat tow out 2017 Jeep Cherokee Trailhawk from etrailer.com. The only part they didn't have was the Mopar Flat Tow Enhancement kit Jeep requires to flat tow this model.
Ordering from them was great, the website is easy to use and I was able to locate all the pieces compatible with my specific vehicle. The expert recommendations help my decision choosing the right parts. I ordered from etrailer even though I found some of the parts on other websites a little cheaper. I chose to pay a little more because of all the effort etrailer has put into installation videos and guides. I was very pleasantly surprised to learn from etrailer that they have a price match guarantee!
So my equipment consisted of the following
Mopar Flat Tow Enhancement Kit (from Jeep)
Roadmaster Battery Charge Line Kit for Towed Vehicles
Mighty Cord 7-Way RV Style Trailer Connector - Trailer End
WesBarg 7-Way, RV-Style Connector w/ 6' Long Coiled Cable Trailer End
Pollak Black Plastic, 7-Pole, RV Blade-Style Trailer Socket - Vehicle End
Hopkins Custom Tail Light Wiring Kit for Towed Vehicles
SMI Stay-IN-Play DUO Supplemental Braking System
Roadmaster Brake-Lite Relay Kit for Towed Vehicles
Blue Ox Alpha Tow Bar - Motor Home Mount - 6,500 lbs
Blue Ox Base Plate Kit - Removable Arms
Blue Ox Tow Bar Cover - Aladdin, Aventa LX, Aventa II
The installation videos are great but not all inclusive. Take the time to read the instructions that come with the parts. This is a major project, I took about 30 hrs over a full week but as you'll see in the pictures I took s few extra steps to make a cleaner look.
Some of those extra steps:
The base plate install requires the bumper be modified cutting off a flange on each side, I spray painted this to prevent corrosion.
In the install video of the baseplate on the drivers side they use an extra quick link (not included) to run the safety cable around the wiper fluid reservoir. I took the time to remove it and run the safety cable behind it.
I didn't want our nice new vehicle to look like it can be towed so I played the brake away switch and 7 way trailer plug behind the license plate, so when not being towed our vehicle looks great!
Some things to be aware of. The Brake air cylinder that mounts to the brake pedal with four bolts may need longer bolts, it did on our Jeep. Spend the money for weather tight heat shrink crimp fittings. The Hopkins wire harness was about 1.5 feet short to get to my plug location. Buy extra zip ties, electrical tape and split loom.
I recommend reading all the various installation manuals and watching all the videos because the various components integrate together and if you install one at a time you'll be doing a bunch of extra work.
The brake light relay is a real pain in the butt, not because of the hardware but because of the location of the brake light switch which is very hard to get to.
Overall I am very happy with the products and how the installation looks. We haven't towed it yet but do not expect any problems.
Roy
7/30/2018
Still very happy with our purchase. We’ve towed over 10k miles and have had zero issues with our tow setup. I’ve shared my experience with several other RVrs and recommended your company for their needs. Thank you,
I read that this is a must have for the Bronco. Evidently the battery can go dead while towing which could cause the Bronco to come out of Flat Tow damaging the transmission. This is cheap, easy to install insurance.
Easy to install and Jeep battery is always charged arriving at the campsites.
Ken
2/27/2026
Great little product. Worked great while we needed it flat towing and the brake controller and lights were being activated. Now the Jeep is babied , trailered and enclosed.
Gwendolyn Y.
2/27/2026
Works great, keeps battery charged while Jeep is towed.
An absolute necessity if towing a vehicle. Easy to install and you won’t have to worry about a dead battery while towing.
Works well keeping our towed battery ch arged!
This kit should come with a diode included. The kit works, but you get feedback to the plug which causes the rear car lights to stay on. I am sure that a diode will fix this problem.
If you are flat towing a Ford Maverick Hybrid, save yourself some grief and add this item from etrailer to the tow package!
Worked as advertised. Keeps towed vehicle battery charged while using Patriot 3 breaking system. Customer service (Dominic) was excellent. Don't get too creative with wire routing. Though the wiring is long enough, there are limitations. I used an aluminum bracket from a rain downspout as a bracket - see picture.
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Condition: Like New
Notes: May have damaged packaging or minor cosmetic blemishes.
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Victoria H.
1/9/2025
That's awesome Ron! I will let them know you reached out.