My trailer's electrical box design

I thought you shot a video of something.

You have inspired me to make a video of my Dream PC 2006...

I have done it before though... quality of video is low but still fun.

Bye, Skybuck.

With all due respect, just buy something already made. If you have to ask here about how to wire up trailer lights, I fear you may not have mastered the requisite skills to accomplish this task properly.

And as such, you may be putting others on the highway at risk. You would almost certainly be putting yourself at risk (as the design engineer & manufacturer) if you were involved in an accident and the trailer light's functionality were called into question...

Please don't interpret my comments as a "dig" on your capabilities, or as an insult. That is not the intent. If you really want to roll this on your own (no pun intended), at least get a qualified engineer familiar with automotive electrical systems to give it a look over.

The rest of us on the highway would surely appreciate it.

-mpm

Iggy has engaged in some truly ambitious projects, far more complex than this. I'd be willing to bet his trailer will be safer than *many* when he is done.

Ed

Agreed. Plus the lighting standard for automotive trailers is rather trivial... any light you buy will be DOT certified.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Thanks. Wiring up trailer lights is not complicated and does not allow for any mistakes (they either work right, or they do not and it is obvious).

What I want, is, first, to have a nice box with terminals, second, an ability to add a trailer mounted battery that can be charged in different ways, and third, LED lights that show me status of brakes and trailer, so that I can double check that everything is working, from my truck's cabin, using a rearview mirror.

i

Fine. May I make a few suggestions then?

1- Ring terminals would provide more security than spade terminals. Especially, if the box is going to be vibrating all over the roadways.

2 - Soldering the crimp terminals is another good idea. I can't tell if you've done that from the images or not. It does not appear so.

3 - The barrier strip can probably be double-nutted, (or nylon captive nut) so it won't swing in the breeze should one side vibrate loose. At least you could dab it with Lock-tite.

4 - I can't quite read the NEMA nameplate, but with this many holes in it, that rating is completely irrelevant anyway. Still, the inside appears pretty rusty. Perhaps it was out of service for a long time.? Or maybe it's not as airtight as you image?. (Think rust, oxidation, poor conductivity, ice pooling, etc...)

5 - I see you have cord protection, but no strain relief. Interesting choice.

Now, let's get to the electroncis:

6 - Many automobiles use a system that causes a more rapid flashing if one of the filaments burns out. Do you plan on implementing such a system with the LED's or some other POSITIVE indication of a malfunction?

7 - The LED soldering job leaves a little to be desired (if the view is the final version, that is..). You have simply lapped the resistor and LED leads side-by-side and soldered them. This should be a FIRM mechanical connection first, THEN a solid soldering job. (Again, think vibration!!.)

8 - The resistors appear to be simple carbon film resistors. Probably OK, but for another penny you could get flameproof resistors. (Always a nice consideration around fuel.)

9 - I cannot see the rating on the 110V cable. It "looks" like standard "SO-type" cord, which of course is an indoor cable and not rated for outdoor or UV exposures. Of course, that's an NEC rating, not DOT, or whatever Standard might be applicable here(?).

10 - Will the transformer be fused, and will the 110V ground connect to the vehicle's 12V ground? In other words, is the isolation of these two systems totally dependent on the HiPot testing of whatever transformer you are using, and do you know what that rating actually is? I don't even want to think about the condition of a hot chasis and a weak ground, or a loop if the trailer happens to touch the building structure while charging under fault conditions. Or, if the trailer is somehow grounded to earth and a fault doesn't clear on the charging circuit branch breaker. (Or, if the neutral to the building lifts, etc...)

11 - Speaking of DOT, who cares if the bulbs & fixtures are DOT rated? Everyone here knows the DOT has never laid eyes on this thing..., so it's totally unfair to intimate their seal of approval. At least on a systems-level.

12 - The idea of dual use (i.e., electronics & glove box / storage) is a novel idea. Ideally, this would have separate access doors or panels, etc... At the very least, there should be a non-conductive cover (and appropriate warning signage) on all exposed 110V. As well as a rigid divider of some sort between the compartments. Possibly something fire rated, depending on what you might want to store inside this thing. Which brings up another issue:

13 - Have you considered the possibility of liquids being stored and what might happen if they leak on the unprotected barrier strip terminal block? Like a lead-acid battery or...[use imagination]

Anyway, I think you get the point. I completely agree that wiring trailer lights is trivial. And probably well within the skill set of everyone here.

My point is:

I've seen enough injury accidents, fatalities and "near-misses" to CONVINCE me that things are NEVER as trivial as they first seem to be. And further, that when one of these "gotcha's" does bite you in the _ _ _, you can always go back and figure out what you could have done differently to better protect life and property.

I've said my peace. You can agree or disagree. And I'm truly not looking for royalties on any of my above suggestions! (Feel free to incorporate!.)

Oh, one more thing. When you do mount the transformer, you might want to use a shock- absorbing mount (rubber bumbers, pads, etc...) Those things are pretty dense. You wouldn't want it flying around inside the cabinet when you hit a pothole (or a deer, elk moose, etc...)

Oh, and of course, the forces involved in an accident are tremendous. So the obligatory statement about making certain it's affixed permanently....

Sorry. One more thing. You mentioned there would be a battery in the trailer box too. If this is a standard lead-acid battery, the charging space needs to be ventillated. (Was this going in the cabinet too?) And of course, the charge would need to be regulated somehow to prevent overcharging, loss of electrolyte, release of explosive gases, etc... But I'm sure you knew all that.

Sorry. One more: What if you have to jump start the truck with the trailer connected? Is this a problem? (From a harness current-carrying point of view.)

Good luck with the project!!

-mpm

Thanks, great points, see my replies.

good point.

I believe that proper crimps done with proper tools, do not need soldering.

There are lock washers under the nuts.

No, it was not at all rusty, it was very dirty but not rusty. Lots of oil grime, most of which I took out.

The 110v cable is going to be almost completely inside the box, with only a couple of inches outside.

The cables going to truck will be tied to the frame, they will not flop around.

My LEDs indicate status of electric brakes, not brake lights.

Yes. That was not a final version.

I will check it out, the resistors seem to be at about 70 degrees C.

The 110v cable will be only used for battery charging, not when riding the trailer.

The transformer acts as a counterweight so that the box does not fall off the table. :) It has no place in the finished product.

I am not sure, here, but all clearance/rear lights on the trailer are DOT approved.

No exposed 110V.

I appreciate.

I guess it is proper to put the battery outside the box.

Should not be a problem, worst case, disconnect a trailer.

u

u -

Is there any 110 inside the box? If not, you might consider a different style connector. People see a standard cord and immeditely think house current.

Just a thought.

-mpm

u -

For the 110 cord, you might also consider one of those NEMA style twist lock receptacles. These could be flush mounted to the box, and then you'd have no cord hanging out!!

I'm thinking a NEMA L5-20R twist lock here..... That's still 110V, but much less common in a residential environment, and thus, much less likely that someone is accidentally going to connect 110 volts to this thing. (I would still search out a low- voltage connector if that's what the design calls for - even if low- voltage / high current.) It is just safer in my opinion.

If you did go with a twist-lock, you could make-up a small adapter cord if you needed to charge it away from "home base". I did not realize the xfmr was not going inside the box.

-mpm

I am going to use 110v for one purpose only, to run a hardwired (no exposed wires) battery "smart trickle charger" when the trailer is in my driveway. So I cannot see much risk of damage here.

i

I don't understand...

In the photo, the box has a standard (110-volt) type plug hanging out about 10-12 inches or so, clamped with a Romex fitting. You later state the transformer is not going in the box.

So what "IS" in the box? And is it going to run on 110 or something else?

And "IF" it's something else, what will happen when some idiot (unknown to you or I) tries to plug this thing into the nearest wall socket.

That is my (safety-related) concern & question.

-mpm

I am going to put in a small 1.5A 110v battery smart charger, in the box, and hardwire it to that 110v cable. Nothing else is going to be connected to 110v. If some idiot plugs it into 110v, the small smart charger will be activated. That's all.

i

Nice welding job. I wonder where you got the welder. :-) :-) :-)

How did you flip the trailer body over & back?

I like the pictures!

Ed

I have a hobart cyber tig that I modified and installed a microcontroller programmed in BASIC.

The source code is GNU copyrighted.

When I brought it in, I used just a chain hoist. When I made a frame on the upside down bed, I used a shop crane to lift the tongue, and chain hoist to lift the rear, and two sheave block to keep it stable.

thanks

i