12 volt to trailer wiring

[LouWon]

Ok, I would like to use a the following
A step 24 V to 12 V step down
The lights
The trailer
Trying to be politically correct, hope the pictures work

 

[DatGuyC]

I also pull a trailer with my Humvee, I did install the led bulbs, but they don't seem as bright, and I want to try the LED trailer lights, but they are not available for the 14 V
So I was going to try one of these, I would need three of them, one for each brake/signal and one for the parking and marker lights
https://www.amazon.com/Nextrox-Conv..._rd_t=40701&psc=1&refRID=54YCCT3TJDTFE1HK6F6P
These are the lights I want to install
https://www.superbrightleds.com/mor...MIzaGmrp743gIVm7jACh1fAAE6EAYYBSABEgLV6vD_BwE

My first idea was to use converters on each wire so I wasn't pulling all the power off the E pin, but I found that the converters don't turn on/off fast enough for a turn signal flash. I tried it on incandescent trailer lights that pull decent power so with LED's the turn signal might not even flash if the converter still has residual power long enough to keep them bright over the flash cycle. I'm also thinking it might shorten the life of the converter if it does a lot on on/off switching but I'm not 100% on that.

 

[McSpeed]

My first idea was to use converters on each wire so I wasn't pulling all the power off the E pin, but I found that the converters don't turn on/off fast enough for a turn signal flash. I tried it on incandescent trailer lights that pull descent power so with LED's the turn signal might not even flash if the converter still has residual power long enough to keep them bright over the flash cycle. I'm also thinking it might shorten the life of the converter if it does a lot on on/off switching but I'm not 100% on that.

I'm happy with just pulling a 12 volt off the back battery and routing through three relays. It is very clean and neat when installed. You can keep the NATO plug in place and just splice into the needed 24 volt signal wires, or tuck it away and replace it with a standard 7 pin or even 4 pin. If using a brake controller, that would need to be wired through the 12 volt battery anyway, then fed back to the pin on the 7 plug so that's no big deal.

I've got about $40 in the whole set up and it seems to be plenty sufficient.

I should have taken pics as I went...but didn't. Maybe I could snap some with it done, but the relays are 100% hidden in the water proof box so you really can't see anything (which was the goal all along anyway).

 

[LouWon]

Yes, the relay set-up is starting to sound good, I think that I will take that rout once I get it out of storage. Thank you

 

[TOBASH]

Subscribed but I'm also considering using your diagrams to make a breadboard circuit board to fit into a box.

Just bought 12 pin connector and once wired I will buy 7 pin connector.

I also will avoid wiring for electric brakes until I need it. Currently just a 4x8 trailer with GVW about 1800lb.

 

[McSpeed]

Let's see how these photos post.

 

[TOBASH]

How many amps do the incandescent (non-LED) tail lights draw? I mean each one separately, and not a total value?

 

[McSpeed]

I would say less than 5 - 10 amps per bulb. Amps x volts = watts. So if you know the watts of the bulb you can figure the amps. These relays will hold a standard trailer on old school bulbs no problem.

 

[cwajciec]

I think normal 1157 bulbs are 30W so around 1.25 amp. Less for marker lights.

 

[DatGuyC]

I used my cable yesterday to tow a little 5x8 trailer with all LED lighting, worked like a champ.

 

[TOBASH]

So, given the step down converters are relatively cheap, I have decided to just buy 3 converters and do away with the relays. Seems more reliable, more easily repairable, and less finicky.

13-15 bucks per step down converter should cover incandescent and LED bulbs.

MHO, and if someone wants to check my math, I'm cool with that.

T

 

[Milcommoguy]

It was noted that the converters are not instant on. Previous posts. That being said, the flashing rate of the 12 volt side will not start or maybe completely interrupted, failing to flash the lights.

The solutions given for the electrically inclined are easy, reliable and simple, building the relay box and one converter. Understand that the converter must be supplied with 24 volts when the master lighting switch is on.

For the electronic inclined my suggestion would to use LM7812ACV voltage regulators in each of the leads feeding 24 volts for the 12 volts lamp circuit. One for left / stop, right / stop, markers, etc. They are dirt cheap (75 cents), readily available, solid state, rated 1.5 amps. This should be fine for flashing one tail lamp or all the LEDS you can muster. If you need a 3 amp load use the LM350T and two simple resistor to set the voltage to 12 Volts.

Advantage = No converter, no moving parts, more or less water proof, cheap and it works.

Search the part numbers and under "data sheets". I believe this is the best way to eliminate this headache for mix and matching 12 volt incandescent lamped / LED trailers... Unless you re-bulb with 12/24 volt LEDs.

From the lab of CAMO, Build it and they will come.

CAMO