Brake Buddy power

Use the 12 volt pin from the MH that would be used to charge TT batteries. You will have to make sure it is wired up. That is what I'm in the process of doing.
You will want to run the ground and upgrade the wiring, to a 6 pin connector on the dinghy.
Got the plugs and socket at the auto parts store along with 14 AWG red and black primary wire. Had the tail/marker light wiring already.

I've know a few who would buy a rechargeable battery jumper unit that had a cigarette lighter. They would put it in the passenger foot well and run the BB cord to that.

Electric auxiliary toad brakes all take more amps (for a short time) than a wire from the coach could provide without excessive voltage drop. Better to use that line from the coach to recharge the toad battery.

Said another way, a charge line from coach can provide low amps 100% of the time. The toad battery can provide the high amps needed for short periods of time when the brakes are applied.

Just make sure your +12V line can feed 15 amps, or your compressor will burn up. Don't ask me how I know.

The preferred method is to have a direct line form your truck battery to a "cigarette lighter" adapter. I think Brake Buddy supply's one now.

Gonzo42 wrote:
Just make sure your +12V line can feed 15 amps, or your compressor will burn up. Don't ask me how I know.

That is just the problem. Supplying enough amps AT PROPER VOLTAGE from coach battery through fuse, wiring, plug and wiring in toad is at best very difficult, more probably not practical.

That is why using the toad battery to power the amps (and it will be at proper voltage since the wire run is a couple of feet, not many yards) and have the charge line recharge the toad battery all the time the coach engine is on/all the time the toad is plugged in (depends on how you wire the coach feed).

I agree with Wolfe10 that the 12V line from the coach may not provide enough current.
I use a 12V outlet with an inline 20 amp fuse wired directly to the car battery. The cord is long enough to reach into the car and the brake plugs into the outlet.
In your case disconnect the vehicle ground cable as recommended in the owners manual and connect the outlet ground wire directly to the battery. That way the two grounds are not connected.

Good luck.

I forgot to add that you will also need a separate ground line from the coach to t h e battery ground so the coach 12V line can charge the truck battery while towing.
This will prevent the brake from running the truck battery dead.

http://www.lslproducts.net/ToadChargePage.html

This is what I use and it works great!

TNTraveller wrote:
I forgot to add that you will also need a separate ground line from the coach to t h e battery ground so the coach 12V line can charge the truck battery while towing.
This will prevent the brake from running the truck battery dead.

If the charge line isn't enough to run the break buddy it won't be enough to charge the dinghy battery.
That is why I make up my own and verify the correct wire size in the MH 7 pin. Same as you do with a TV pulling a TT.