Best path to 12v battery for flat towing

[Bill Aggie]

I was curious if there is a shortcut pathway to drop a 12 volt line to the Maverick 12 volt battery from the back of a motorhome. I realize there are probably a number of ways to get to the battery but I was curious to know if there's a shortcut possibly a tap under the hood that gets to the battery versus trying to penetrate a firewall or by what other means necessary to get to the 12 volt.

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[mapnerd]

Why do you need to penetrate the firewall? Or are you talking about going from the Maverick battery into the Mav cabin to power the auxiliary braking system?

I used the Demco AF1 for many years pulling my F150 and was very happy with it. We went through the firewall on that truck using the existing penetrations, the grommets usually have just enough space for one or two more lines to come in.

 

[Bill Aggie]

No I want to go from the back of my motorhome where there's 12 volts to the 12 volt battery in the Maverick to keep it charged while being flat towed. If the battery dies the flat tow mechanism also fails

 

[mapnerd]

Then you don’t need to go through the firewall (at least not for that). You may need to install a kit, but the back of your motorhome will have a tow bar and electrical wire. That electrical wire from your motorhome will terminate with a typical 7-pin connector. The 7-pin carries a 12v aux which will be connected to your Maverick battery and will trickle charge the Mav battery from your motorhomes 12v electrical while towing. The others will be used to activate the Mavs lights brake and turn signals according to what signals your motorhome is sending, as well as brakes on the Mav as well.

depending on your tow vehicle’s aux braking system, you likely may still need to send 12v in to the cab to power that system correctly.

what kind of motorhome do you have, which tow bar and which aux braking system?

 

[Bill Aggie]

I haven't purchased a brake system yet. Its on my list. I have a 2016 Challenger. My question is how do you get to the 12 volt to charge the battery? Yes I realize I could connect directly to the battery but I was looking to see if there was some place to pick it up under the hood.. if anyone's had any experience with that. I'm trying to keep the 12 volt battery charged while under tow using the 12 volts for my coach. I understand I have to isolate it with a diode so that the Maverick cannot back feed the coach.

 

[mapnerd]

This or something similar gets installed under the hood: https://www.etrailer.com/Accessories-and-Parts/CURT/RVI74FR.html

 

[mapnerd]

2016 Challenger, that’s a gasser iirc?

 

[fastgascar]

Just run the positive to the jump post under the hood and the negative to any factory ground.

 

[MakinDoForNow]

I haven't purchased a brake system yet. Its on my list. I have a 2016 Challenger. My question is how do you get to the 12 volt to charge the battery? Yes I realize I could connect directly to the battery but I was looking to see if there was some place to pick it up under the hood.. if anyone's had any experience with that. I'm trying to keep the 12 volt battery charged while under tow using the 12 volts for my coach. I understand I have to isolate it with a diode so that the Maverick cannot back feed the coach.

I just checked my noco 5g on my 2022 hybrid lariat. Looks like it's on standby after running my approximately 90 days charge followed by the optimization/desulfation routine. ETA: The rectangular cover to a threaded jump post tips towards the front of the truck.

 

[Bill Aggie]

Yes, gas.

 

[mapnerd]

ok. pretty sure that's on the ford v10 chassis and pretty sure that chassis uses hydraulic brakes. I would consider you look at the Stay-In-Play Duo system from Demo (https://www.demco-products.com/rv-towing/supplemental-brakes/stay-in-play-duo) for your supplemental braking system.

For your charge line, there are plenty of kits for that. Personally, when it comes to the importance of these systems I like to keep them all in the same brand to maximize compatibility and ensure things work, so inline with the above recommendation I'd offer this for your charge line: https://www.etrailer.com/Accessorie...YXmNDSQa5xbc_7PF-6-n6KNOGY9jIVChoC2GoQAvD_BwE.

I would still strongly recommend a charge system like the one that @MakinDoForNow or I recommended previously. These systems will prevent your towed vehicle from charging your RV's battery and also manage your battery for you, ensuring it charges only when it needs to.

You might find better advice over on rvforums.com. Lots of very experienced and knowledgable folks there that do this every day.

 

[fastgascar]

I use a blue ox tow bar with a roadmaster baseplate, RVIbrake3 for the auxiliary brake,towed charging system, remote breakaway and tpms all works in harmony. I plan on upgrading to the roadmaster nighthawk as the lights that are integrated into the arms is a nice feature when traveling at night. Until then I use a tow-n-glow

 

[Yetiman]

As previously mentioned, the best thing is to use the jump points in the hood to to charge the Mav battery when towing. I installed an RVI Brakeshaow unit on my Mav and that has a built in battery charger function. Double check your RV. I have a 2018 Coachman, and Coachman does NOT run a 12v hot line to the 7 pin terminal on the back of the RV. I had to run a 12ga fused line from the battery to the 7 pin on the rear of the RV.

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