Striking our Colors and Raising New Ones

BrucePerens · 08-01-2017, 11:00 PM

I've been doing a lot of DC wiring in my Trailmanor, for ham radio, extra DC outlets, and various accessories. The wiring that came with my Trailmanor used black for 120V hot and white for 120V neutral, and black for 12V DC hot and white for 12V ground.

Using the same colors for these two functions is asking for electric shock and mis-wiring.

I finally chanced upon the fact that UL 1426 Safety Cable for boats is available in a pair with red for DC hot and yellow for DC ground. UL 1426 cable is made to a very high specification for commercial vessels.

I am now using Ancor marine grade wire with conductors in red and yellow and a white sleeve. It's really pricey, but you can get it online for about half the price of West Marine. And it will last forever. Much nicer than all of that zip cord and speaker wire.

SMCrane1554 · 09-14-2017, 02:26 PM

Mr. Perens,

I need to connect a Tire Pressure Monitor Bluetooth signal booster to a 12V DC source that is on whenever my TM3326 is in motion. I will probably have to run hot and ground from the source to a point closer to the front of the TM so that the signal booster can talk to the Tire Pressure Monitor in the cab of our truck. What point would you suggest as a beginning connection point? There is a junction box under my TM with a lot of light-gauge wiring in it, which I suspect is all 12V DC. The signal booster has two alligator clips on the electrical leads.
Thanks,
SMCrane1554

**Bill** · 09-14-2017, 04:14 PM

Many people take the power connection from the running lights. Handy. But it means you have to remember to turn the running lights on when towing - which is not a bad idea anyway, and should easily become a habit.

I'm not sure what the junction box under the TM might be, but I'm sure it is not the box that feeds the air conditioner (120 VAC). Right?

And of course, when you finalize your connection point, you will cut off the alligator clips and throw them away. Right?

Bill

SMCrane1554 · 09-14-2017, 05:37 PM

Quote:

Originally Posted by Bill

Many people take the power connection from the running lights. Handy. But it means you have to remember to turn the running lights on when towing - which is not a bad idea anyway, and should easily become a habit.

REPLY: The manual says to connect to an "always on" 12V source.

Quote:

I'm not sure what the junction box under the TM might be, but I'm sure it is not the box that feeds the air conditioner (120 VAC). Right?

REPLY: Correct. There is a box with a whole lot of small-gauge wires of different colors that appear to be 12V DC.

Quote:

And of course, when you finalize your connection point, you will cut off the alligator clips and throw them away. Right?

REPLY: That is the plan.

BrucePerens · 09-14-2017, 09:13 PM

Just call me Bruce, please.

I put that big TireMinder repeater under the front of the trailer on the street side, where it is out of the rain, with the antenna pointing down. It's on the street side, as is my battery cut-off switch, so that it won't attract the attention of curious passers by on the sidewalk. It's attached to the frame with some wire ties. It works, which is more than I can say for the Dill tire monitor I had before.

I ran it to the house 12V in the trailer, because I had already installed a secondary fuse block under the street-side couch and had an existing hole to run the wire through. But it has a big bright green LED which is on all of the time, and a battery drain that I'd rather avoid when not towing, and I don't need it to interfere with the ham radio. So I like the idea of having it on only when the Bargman cable is connected to the tow vehicle.

To get 12V only while the Bargman is connected, you need to put a diode in series with the 12V line from the Bargman to the converter, with the positive end of the diode toward the converter, and then tap off the negative end of the diode to go to the repeater. Otherwise, you get the 12V from the converter coming through to the Bargman all of the time. If the diode works correctly, the tow vehicle powers the trailer and charges the trailer battery (with no current regulation) and the trailer battery will not power the tow vehicle. Use a 30A or more Schottky diode meant for bypassing solar panels, with at least 24V breakdown voltage. They are $5 on eBay. Silicon diodes have a 0.7V voltage drop, A Schottky diodes voltage drop is current-dependent but usually much lower than silicon. Your tow vehicle probably has a 15A fuse on the Bargman 12V line, and most Trailmanors have a 30A fuse on the battery, so 30A is likely a safe rating for the diode.

It probably also works to put the repeater under the back of the two vehicle and power it from the tow vehicle.

tentcamper · 09-16-2017, 11:50 AM

I would run a wire behind the fridge and connect it to the 12v feed wire for the radio antenna power amp. I belive its a 12 gage wire for that fraction of an amp needed for the radio antenna amp.

If you have a power jack, you could tap into that wire for you power. But it would always be powered.

SMCrane1554 · 09-30-2017, 07:38 PM

There is a single black wire running to the Atwood tongue jack on our TM. The TM schematic shows it as a 30-amp circuit. If I connect the positive lead of the TireMinder booster to the black wire, to what should I connect the booster's negative lead?
Thanks,
Stewart Crane

Shane826 · 09-30-2017, 08:07 PM

Frame ground

BrucePerens · 09-30-2017, 11:46 PM

By "frame ground", he means any screw that's driven into the metal of the front A-frame near the jack. There is one just for the ground connection, but you can even drill a hole and drive a new one if it's convenient.

SMCrane1554 · 10-06-2017, 07:55 AM

Got our TireMinder Bluetooth booster installed on our TM 3326. I mounted the TireMinder booster on the angle iron which supports the bottoms of the propane tanks, so it is somewhat protected. I attached a metal surface-mount water-resistant junction box to the TM chassis, then ran the tongue jack's hot wire and the TireMinder wire into the box, where I connected the TireMinder's positive lead to the tongue jack's hot wire. I connected the TireMinder's negative lead to the ground screw in the junction box, and it works fine. I intend to get some wire loom to protect the wires which are exposed to the weather. With a GPS and the TireMinder mounted on the windshield, our tow vehicle looks like the cockpit of a fighter jet. Thanks to everyone for your input.