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The_Works's avatar
The_Works
Explorer
May 23, 2016

Tow Vehicle Charge Wire

Our 2013 Winnebago Itasca Meridian has the factory installed 7 pin trailer/tow connector on the rear of the coach. The connector cover shows the turn/brake function of each pin plus a - pin and a + pin. I measure +12vdc on these pins. I'm going to assume, for now, this is the charge wire for the tow vehicle battery. I have a 2016 Chevy Equinox tow vehicle with the Patriot brake system that drains the battery when were using it. The vender where I bought the coach was suppose to install a charge wire but when I measure across the tow vehicles dead battery while connected to the running coach, I measure 5.5vdc. The vender did install a 2 conductor cable from the tow vehicle Blue Ox connector to the tow vehicle battery but it appears they did not connect the two wires on the correct pins on the connector. Further looking at the 2 conductor wires the vender installed, they have both conductors connected to the positive side of the battery, no negative or ground connection. Seems to me since the coach is providing both + and - connections, one would connect on conductor to the + and the other conductor to the tow vehicle ground. Seem correct? My first question is, is my assumption correct that the coach +12vdc is the charge voltage for the tow vehicle? Second question, should the - side of the coach provided 12vdc be connected to the tow vehicle chassis/ground? Thanks for your time and input.
  • The_Works's avatar
    The_Works
    Explorer
    May 24, 2016
    WyoTraveler wrote:
    Assuming that both your tow vehicle and MH has a minus ground then yes both chassis are common ground. Go to etrailer dot com and they will have plug wiring diagrams. My MH has +12 volt available on the trailer socket whle my ignition key of the MH is on. However, some MHs have some wiring wired to the other side of the relay. For example, my MH requires the ignition o be off before I can operate the slides. Therefore the toad battery will feed back into your Mh. Solution is to add a diode in that charge line. Radio Shack has some cheap 6 amp diodes. If I recal 3 for about $4. I mounted 3 in parallel in a small Radio Shck project box. It prevents your toad battery from feeding back into your MH when the ignition is off. I have measured the charge current and my charge current has never been above 10 amps.

    I made up my own cable connecting my MH to my toad. 7 pin on the MH to 6 pin on the toad. I have used the diode isoltion for 3 years and works well. I also use the Patriot braking system.

    Thanks WyoTraveler for the input. I looked at the BlueOx website and they sell the blocking diodes but I'd rather do what you did. My question is, you have a positive 12vdc coming from the coach, connecting to the three parallel diodes, do you connect the +12vdc coming into tow, prior to connecting to the battery to the anode(+) or cathode(-) side of the diodes? Thanks for the info and your time, safe travels.
  • WyoTraveler's avatar
    WyoTraveler
    Explorer
    May 23, 2016
    I have about $10 to $12 invested in my charge line. I think the brake buddy charge line with fuse and diodes is about $25. Not a bad price if you don't have the time to build one. It should work as well with the Patriot as the Brake Buddy.

    For me it is just more convenient to know my toad will start anytime. If I were to break down on a trip at least I don't have to worry about if my toad is going to start every time.
  • Gonzo42's avatar
    Gonzo42
    Explorer
    May 23, 2016
    Brake Buddy also sells the diode and fused charge line. They also say their system will not discharge the battery until about 3 days of use.
  • WyoTraveler's avatar
    WyoTraveler
    Explorer
    May 23, 2016
    Assuming that both your tow vehicle and MH has a minus ground then yes both chassis are common ground. Go to etrailer dot com and they will have plug wiring diagrams. My MH has +12 volt available on the trailer socket whle my ignition key of the MH is on. However, some MHs have some wiring wired to the other side of the relay. For example, my MH requires the ignition o be off before I can operate the slides. Therefore the toad battery will feed back into your Mh. Solution is to add a diode in that charge line. Radio Shack has some cheap 6 amp diodes. If I recal 3 for about $4. I mounted 3 in parallel in a small Radio Shck project box. It prevents your toad battery from feeding back into your MH when the ignition is off. I have measured the charge current and my charge current has never been above 10 amps.

    I made up my own cable connecting my MH to my toad. 7 pin on the MH to 6 pin on the toad. I have used the diode isoltion for 3 years and works well. I also use the Patriot braking system.

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