Auxillary battery for Patriot brake system

[kathydavidb]

My owner's manual says I need to do a battery cut off switch when towing my 2017 Ford Edge behind my motorhome. The only problem with that is my Patriot brake system plugs into the cigarette lighter plug.(12V). Did any one ever use and additional 12v. battery for the Patriot to plug into? I think Ford does not want a charge line to the MH due to the many electronic devices it now has. So, I want to do as they wish but then need to have another 12v. battery source to power the Patriot brakes. ANY help or info. appreciated.  Dave

[Mark and Dale Bruss]

My 2018 Equinox had the requirement for a battery disconnect.  I put a battery switch on the Negative terminal of the battery.  Directly to the battery terminals, I wired a 12 Volt receptacle and also a battery charger that connects to the motorhome.  Thus the brake system has power and yet the car electronics are disconnected.

[Kirk W]

While mine was for a Brake Buddy, I did install a separate 12V power plug for it that was wired around the battery isolation switch on one of our towed vehicles. It isn't a big deal but make sure that you put an "in line" fuse between the battery and the socket. Just connect the lead from the socket to the battery side of your switch.  Unless your Patriot draws more than the BB you will be fine for 6 - 8 hours of towing without any charging. In more than 20 years of towing with a Brake Buddy using the towed battery to operate and no charging wire from the motorhome, I never had any problems caused by it. 

[oldjohnt]

Kathy & David, here's the conflict you face which it sounds like you're very familiar with.

 If you place a load on the non running toad battery over long enough time (time subject to current draw)  periods it obviously eventually discharges if no charging method is utilized WELL DUH

 However "Ford" to cover themselves has to advise against it, so what's a person to do????????

 What I do (NO Warranty and I'm NOT saying void your warranty or disobey Ford lol) is to run a properly protected at BOTH ends remote charge wire so when driving the motorhome provides at least "some degree" of charge to the toad battery. Its of course ONLY in place and in use when the motorhome is physically plugged to the toad via the cord and plug so there's no other isolation issues.  Since BOTH the motorhome and toad battery provide "some degree" of buffering and stability (in a way like a huge capacitor) and can possibly reduce spike or surge problems I PERSONALLY to date haven't had any problems with spikes or surges harming my toads electronics BUT I CANT SAY WHAT YOU MAY EXPERIENCE !!!!!!!!!!!!!!!!!!!!

How much and what quality of charge the motorhome when driving may actually net deliver to the toads battery DEPENDS on the length of wire and wire gauge and resistance of plugs and receptacles etc etc but in my experience it doesn't take much to maintain the toads battery ALL SUBJECT TO TOADS LOADS.

While I ran a charge wire via plug and outlet (NO isolation problems) and it works great I cant say what you should do THATS YOUR CALL 

John T