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Trailer pigtail on a 6 volt truck.


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I have a 1954 International R110 pickup that is all original... still running the 6volt electrical system... and I'm almost done restoring my 1954 Crestliner boat that I would like to pull behind it...  I drive both vehicles pretty regularly. I was wondering has anyone wired a trailer pig tail to a 6 volt system?  How'd it work with the trailer? I also pull the boat with my late model pickup so if possible I'd like to use 12 volt bulbs and what not on the trailer...  just curious what you all have done, or what you think...  trying to get ideas before I finish the trailer.

 

 

Thanks

 

 

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Use those tail lights that the plastic lens pops off with a screw driver.

Swap bulbs accordingly.

12 volt bulbs powers by six volts will be disappointing.

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You might want to consider using 6v LED lamps for your trailer when it’s connected to your old truck.  They would not strain the truck electrical system and the turn signal flasher might even still work ok as the LED current draw is small compared to regular incandescent bulbs.

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The trailer pigtail neither knows nor cares what the voltage is.  So long as the bulbs are correct, you're fine.  Of course, 12V trailer brakes will NOT work with your 6V system. The other potential problem is that voltage drop due to the longer wires and typical questionable trailer wiring practices will be exacerbated by the lower voltage.  Half a volt drop is a much greater percentage of 6V than it is of 12V.

Edited by joe_padavano (see edit history)
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Thanks guys!

Sounds like just swapping bulbs between rigs might be the way to go. 

 

I appreciate the info... gonna start restoring the trailer here soon. 

 

I'm pretty stoked to have a truck, and boat with a outboard motor all the same year. It's been a very fun project.  Hopefully I can post some pics soon and show her off

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3 hours ago, Hans1 said:

but do not trailer w/ 6 volt car.

Why not, what has voltage got to do with towing ability.  I have towed a 27' float with ten or fifteen people on it in a parade for years.

I have also flat towed (towbar) a 26 Studebaker, a 52 Studebaker and a 29 Buick hundreds of miles with my Pontiac.  Never had a problem except when the 26 blew a rear tire and that had nothing to do with voltage.

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I just had another thought.

I think I was talking to one of those guys with all the LEDs on display at a car show one time and he commented that some of his stuff would work 6 or 12 volt.,

They would most likely be polarity specific but a possibility.

 

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On 4/18/2019 at 2:01 PM, JACK M said:

I just had another thought.

I think I was talking to one of those guys with all the LEDs on display at a car show one time and he commented that some of his stuff would work 6 or 12 volt.,

They would most likely be polarity specific but a possibility.

 

I was just researching that myself... they do have some leds that can range in voltage fro 5 through 24v.

 

I'll deffintily be looking into getting some that'll be universal for both my rigs.  

 

Thank you

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I can't answer exactly, but here's some food for thought.

 

It is always a good idea to use relays to trigger the lights on the trailer. It might matter less with LED's, because they draw less current. Back in the day, cars that towed had a lot of trouble with melted wiring, switches, etc, because you typically tapped into the lights at the back of the rig. The headlight switch, signal switch and the brakelight switch often weren't big enough for the current draw of extra bulbs on the trailer. The wires themselves were often too small and ran hot. By the early 70s, many factory tow packages used relays.

 

If you are required (or are going to) have a breakaway switch on the trailer, and you have to carry a battery on the trailer anyway, you could put the relays on the trailer instead of the tow vehicle(s). You could probably find some 12v relays that would trigger reliably on 6 volts. The relays wont care if they see positive or negative ground (just don't get junkyard ones with a diode inside), and so it would solve any polarity issues.

 

In the 50s and 60s, I don't think the voltage of the trailer brakes was an issue. They were adjusted with an adjustable resistor block under the hood of the tow vehicle. If the brakes are "of the era" they should be fine, but you may need a resistor block in the 12v vehicle, or better yet both of them. If the brakes are modern, I can't comment.

 

Another trick that could be done (and I have not personally tried this), is to run a tiny 12v alternator (Geo Metro or Kubota) in the 6v vehicle, and hide a small 12v battery somewhere. The 12v system could be negative ground and coexist even if the 6v system was positive ground.

 

And yes, you can tow with 6 volt vehicles. In the 20s, my grandparents built a "House Trailer" for camping that looked a lot like the "tiny houses" you see people building on trailer chassis these days out of regular building materials. In the 30s, my grandfather drug it up to Grand Coulee with a 27 Studebaker to work on the dam. A Lincoln "L" and a Packard 120 were among other vehicles that pulled that thing around. After the war they got a factory-built trailer. Much lighter. Still 6 volts.

 

One thing to keep in mind when towing with old rigs like your 1950s pickup, is that 50mph was maximum towing speed period, and that was under ideal conditions. Of course it was much slower up hills if you didn't have a powerful rig, and down them to keep the speed under control and the brakes cool. As recently as the 80s that was still true. I know that everybody today has a diesel 1-ton dually pickup, and an equalizer hitch, and a swaybar and so on and they tow at 70mph on the freeway. It makes me nervous. You just NEVER did that with the old equipment. Be safe.

 

 

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6 volts  system will  not work  on a 12 volt system efficiently. Use 6 volt bulbs on the trailer. You can buy readymade magnet tail lite assemblies with either 6 or 12 volt L E D . All wired up and ready to go. The  trailer brakes  must match the voltage you intend to use. I will not compromise safety. In an emergency you might end up in a pretty nasty situation.   

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14 hours ago, trini said:

6 volts  system will  not work  on a 12 volt system efficiently. Use 6 volt bulbs on the trailer. You can buy readymade magnet tail lite assemblies with either 6 or 12 volt L E D . All wired up and ready to go. The  trailer brakes  must match the voltage you intend to use. I will not compromise safety. In an emergency you might end up in a pretty nasty situation.   

 

Not likely that this boat trailer has electric brakes.

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