I tow a 2012 Honda CRV with a Roadmaster BrakePro that plugs into the 12V outlet on the CRV consul, behind my Winnebago gas motorhome. After I tow 100 to 200 miles the battery in the Honda goes dead. I've been told I need a charge lead from the motorhome to the CRV. I need information on how to do this. Any help would be appreciated.

This Toad Charge kit should do the job safely (comes with instructions).

OR put a fuse bypass switch into the radio circuit - the one described in the CRV manual for "extended towing" - that'll reduce the battery drain so the brakes won't kill the battery. That's what we had to do to our 2012 CRV.al

Your Winnebago may have this prewired at the coach side. If I recall (don't take my word!) it was a black wire on mine. Then from the receptacle on the toad direct to the battery positive. Voila.Or, use the kit described above!

obgraham wrote:Your Winnebago may have this prewired at the coach side. If I recall (don't take my word!) it was a black wire on mine. Then from the receptacle on the toad direct to the battery positive. Voila.Or, use the kit described above! Pretty close to all that's needed. 03winnead, There's really no need for any "Kit" of any type or manufacturer. All that's needed is what you already know, a charge line directly from the coach trailer plug, through the pig tail, and then, up to the positive battery post on the CRV. Now, first off, the first thing to do is, determine if, you have a 12v pin, in that trailer plug, that's hot, either with the ignition on or off. Many of the 7-pin plugs are pre-wired with such a hot lead and it's normally labeled on the door of that plug, which one it is. You can do the simple test with a 12V test light. Just clamp the ground clamp to any good clean source metal and then probe the appropriate pin and see if it lights up the light. If it doesn't, and the ignition is OFF, then try it again with the ignition "ON". If it still doesn't, then, you've got find out why. If it's not there, on the back sided of the plug, well, then you've got to set one up or, find the one that's supposed to go there. Now, if it does light up the test light, either with the ignition of the motor home on or off, then you're half way home. Now, all that's needed is to continue on, that same hot lead, through the pig tail, into the car and up to the positive lead on the CRV battery. And yes, do install a fuse, anywhere in the line that makes you happy. Some get carried away and add TWO fuses, one near the trailer plug and the other one near the battery post. Your choice. But, with that system, which, is seriously cheap and easy to set up, you'll be just fine in sending a charge to the CRV battery while towing it down the road. If and when you get all this done, then start up the motor home and check the voltage at the pin on the trailer plug on the coach, then check it at the CRV battery post and compare to see if there is any voltage loss in that new system you just set up. Good luck.Scott

I agree with adding the charge line, especially with and aux brake unit plugged in. Even with pulling the recommended fuse, the Honda battery will not last. We accidentally left a reading light on while getting groceries and within a hour the car would not start. Also if we don't start the car for 3 or 4 days, dead battery. Canadian Honda dealer says no problem, wont replace under warranty, Florida Honda dealer says the battery has a short in it and needs replacing but the cant do it under warranty, want big dollars.Your Winnebago should have a charging 12v already in the 7 pin receptacle. The 12v is only live, when the MH is running. We added a line from the CRV receptacle to the Honda battery, 15 amp fuse just before the battery. No problems when towing.Beverley and Ken

charge lead from motorhome to toed | Good Sam Community

DaveG39
Explorer
Sep 08, 2013
I used 10 gauge - easier fit into connector.
FIRE_UP
Explorer
Sep 11, 2013
DaveG39 wrote:
I used 10 gauge - easier fit into connector.

Yep, I agree, the 10GA will work just fine. We towed our '11 CRV all over the western U.S. with a charge line in place and never pulled any fuses. That Honda engine started perfectly fine, each and every time. A check every now and then at the positive post of the CRV battery always revealed between 13.2 and 13.7V. while hooked to the coach and the coach running.
Scott
j-d
Explorer II
Sep 11, 2013
Those with Hondas are supposed to start the engine and go through the gears every so often, right? Does the charge line have to be disconnected? I can see where if one battery was low, the charge line would try to act as a jumper cable and get really hot.
FIRE_UP
Explorer
Sep 11, 2013
j-d wrote:
Those with Hondas are supposed to start the engine and go through the gears every so often, right? Does the charge line have to be disconnected? I can see where if one battery was low, the charge line would try to act as a jumper cable and get really hot.

j-d,
Well Sir, yes the Honda manual, if I recall, mentioned something about only towing for around maybe 6-8 hours or so and then a break was needed to start it up and run it through some gears. I can't remember and someone that's still towing one I'm sure will verify or correct me on that.

Now, as for your assumption of the "charge line" acting as a jumper, well, if it's doing it's job correctly, as in charging the CRV battery, then the Honda starts in about 1-2 seconds, each and every time so, the potential for that charge line getting over heated because it's still connected to the coach, I think is nil. Besides, I (along with most folks) installed a fuse in it so, there's a built in safety factor there too.
Scott
Sooboy
Explorer
Sep 11, 2013
j-d wrote:
Those with Hondas are supposed to start the engine and go through the gears every so often, right? Does the charge line have to be disconnected? I can see where if one battery was low, the charge line would try to act as a jumper cable and get really hot.

I have a charge line setup like FIRE_UP suggests in his post above. Just came back from a trip to Moab, UT and back....and experienced no issues. I've never unhooked to start-up and go through the gears.
Olddud
Explorer
Sep 12, 2013
I installed a charge line from my Winnebago Cambria through the 7 pin connector and then to the battery, using 12ga. wire. It is fused at 10amps at the battery.

Recently, I had a Brake Buddy failure where it ran continuously for 30 minutes and nearly burned up the connector inside the Jeep. The fuse held on the charge line. So the charging line must have never exceeded 10amps. I have since wired a new connector made for the purpose for the BB.
DaveG39
Explorer
Sep 12, 2013
If the charge line is doing its job the car battery will remain charged and the charge line will not overheat. If you are concerned, you can disconnect the umbilical before starting and the charge line will be an open line and not be able to overheat. Then reattach after starting. You would only need to do the starting while tied to motorhome when towing for longer in a day than the car book recommends between starting and putting car through gears.
j-d
Explorer II
Sep 12, 2013
More I think about this, I'd want a relay or some solid state device (that I am incapable of understanding much less designing) that would isolate the two vehicles' batteries when the coach was not running. Otherwise, leaving something ON in either vehicle would run both down.
Starting toad with coach not running (and a relay or such) would not affect the charge line. Starting coach with toad connected would, unless the ACC terminal isn't powered while key is in START which might be true.
Maybe just too cautious... I just think about one vehicle's battery getting low somehow and the other battery trying to crank that vehicle through the charge line. But if all it does is blow a 10A fuse, not so bad...

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