Trailer Plug: Where Can/Should I get 12V for Trailer Battery

[FFaust]

Any suggestions as to where I should get the 12V to charge my trailer battery through the trailer connector on the coach?

I would prefer a switched power source and am considering tapping into the output of the Xantrex echo-charger.

Any better ideas out there? Where do you get yours?

[palehorse89]

I ran a #10 wire from the batteries to a 20 amp auto reset circuit breaker and the to the 7 blade plug on the Coach. If you desire to be able to switch the power on/off, just install a toggle switch that is rated like the breaker.

[dpinvidic]

I would keep everything on the Chassis side (don't use House batteries).
On my Phaeton, the 12V to the trailer plug goes thru a relay which is controlled by the ignition.

The benefit here is that it disconnects the toad charge line when the ignition is off. This prevents any current draw FROM the Toad to the Coach when you are parked. Or you could use a isolator module which you can purchase from amazon.

Battery Maintainer

Regards,

Dan

[tom chelbana]

Your 7 way plug should have a 12 volt charge terminal on one of the terminals we use to charge the tow car. Use a test light to see which terminal is hot all the time.

[FFaust]

Thanks guys.

Chassis side for sure; I am struggling enough as it is to manage the house batts without adding extra loads.

Reason I would like a 'switched' source is so that the trailer doesn't drain the chassis batts when parked, but then I could just disconnect the trailer plug when not needed.

I have checked the plug for voltage on the proper pin but there is nothing. That's why I'm trying to find a wire that I could use back in the engine bay.

[nothermark]

FWIW If you are dealing with a Ford chassis the 12 VDC is controlled by the ignition switch. The key needs to be on to get power.

[JohnFreyja]

Francois did you check for power when the ignition was ON?

[FFaust]

Originally Posted by JohnFreyja

Francois did you check for power when the ignition was ON?

Couldn't remember if I had, although you would think so, so I just did, and no, there is nothing. Thanks for asking.

Haven't undone the connector on the coach, but I'm pretty sure that there is simply no wire connected to it for power, which is what I have assumed until now.

BTW, unless I am reading it wrong, I don't understand what CC is trying to do in the owner's manual, on page 3.20:

It sounds as thought the coach came with the 7-pin plug pre-wired but with a loose equipment pigtail to wire into the trailer. Only problem is that the way CC tells us to wire the plug makes no sense to me, it is different than 'standard' way???

BTW, it looks as though I just gone through my second tail light converter, sheesh. I'm certainly open to suggestions here.

This is what I'm talking about:

[Mr_D]

When we bought the Magna we were assured several times that the #4 pin was wired to carry power to the van. The shop foreman had to come in on a Sat and wire it because CC didn't do it on our rig. He wired it through from the relay/wiring compartment under the driver.

[FFaust]

Thank you, that's what I think is going on here.

We've had it for a month and are still trying to tame the beast. So far:

Slide-out leaks.... check
Smart wheel controller (cause we lost all running lights).... check
Trailer connection.... getting there

Next stop, house batteries: We have only two 4D batts (spec says they should be 8D). They are recent but the voltage goes down by 1V overnight, so I might try to add a third 4D, a third 8D, or maybe convert to 6V Group 31.