scroxfo Report post Posted June 21, 2017 I have a 2013 Ford Explorer that I tow 4 down. Car battery goes dead during long pulls. Is it really that complicated to charge the car battery off the coach's chassis battery while towing with a single wire harness from battery to battery?? Share this post Link to post Share on other sites
rossboyer Report post Posted June 21, 2017 Should be easy to do. On my coach I have one of the big 6 conductor and big center post trailer connector. One of those is unused, so just add +12 volt line, but add a diode to restrict the towed's battery feeding back to the coach. Don't know what tow bar you have, but I think you can contact Roadmaster for information. I think they sell a complete kit to charge a towed vehicle's battery. Share this post Link to post Share on other sites
scroxfo Report post Posted June 21, 2017 thanks. I am sporting a blue ox and buddy brake (wish I could get a mulligan on that one) Share this post Link to post Share on other sites
rossboyer Report post Posted June 21, 2017 Should be easy to do. On my coach I have one of the big 6 conductor and big center posts. One of those is unused, so just add +12 volt line;, but add a diode to restrict the towed's battery feeding back to the coach. Don't know what tow bar you have, but I think you can contact Roadmaster for information or look on their web site for wiring diagrams. I think they sell a complete kit to charge a towed vehicle's battery. Just because you have Blue Ox shouldn't make any difference. Share this post Link to post Share on other sites
wolfe10 Report post Posted June 21, 2017 Yes, several ways to do this. You could use a diode as Ross suggested, but a regular diode looses .7 VDC to heat. Another option is to use a relay triggered by an ignition-hot source, in indeed you only want charging when the coach ignition is on. A few bucks more, but full voltage would reach the battery. If you always disconnect the toad when not driving the coach or are on shore power so coach battery is being charged, no need for even the relay-- just wire using the parts listed below. Parts: Fuse at positive terminal of BOTH coach and toad battery. 8 gauge wire for both positive and ground. Share this post Link to post Share on other sites
manholt Report post Posted June 22, 2017 Welcome! Why does your battery go dead? Share this post Link to post Share on other sites
kaypsmith Report post Posted June 22, 2017 As Brett said, but be sure to use two wires to your battery as he stated, I emphasized this because many try to use only a hot wire and no good ground from the coach will cause sporadic charging of the toad battery. Share this post Link to post Share on other sites
fad847 Report post Posted June 22, 2017 I have a 2011 Honda Crv and I installed a TOAD-CHARGE System. Simple hookup and is has a diode in the system with indicator lights to tell you it is connected properly, charging, reverse polarity. Haven't had a dead battery yet. 4 years so far. Share this post Link to post Share on other sites
ltmoeller Report post Posted December 18, 2017 I know his is a old post but on my 2013 Ford Edge my 12 volt ports go to sleep in 30 minutes so I installed an auxiliary 12 volt direct from battery to power my RVi 3 braking system and chargewire kit from rv to car.No problems. Share this post Link to post Share on other sites
wayne77590 Report post Posted December 18, 2017 Okay, old but still relevant. 2013 Lincoln MKX and after 4 hours and stopping battery would not have enough juice to start car. Hook up charger while doing set up and unhooking, probably 10-15 minutes and car started right up. Dilemma for sure since manual said to start and run for 5 minutes every 4 hours. Cured by stopping every 2 hours and running the engine for 5 minutes. Gave me time to do the "stand-up," and stretch my legs. Never had a problem after that. Share this post Link to post Share on other sites
martysantic Report post Posted December 18, 2017 I installed the RVi charger. Cheap and works great! Share this post Link to post Share on other sites
