EZ 12V Power Adapter for Pickups & SUV's

[bdhsfz6]

I got tired of having to pop the hood every time I wanted to connect alligator clips to the battery. Cigarette lighter sockets used to be a convenient place to tap into 12V power, but many new vehicles don't have them. They are also limited to less than 10 amps and often controlled by the ignition switch. This simple, cheap adapter makes it a snap to hook up portable compressors, 12V tools, battery chargers, etc. without having to lift the hood.

It works on any vehicle with a 7 pin trailer wiring harness connector, and provides a convenient place to connect alligator clips. Most pickups and SUV's have a 20 - 40 amp trailer auxiliary circuit which is always on and not controlled by the ignition switch.

It's made from a trailer harness plug such as this one:

Amazon.com

Using #10 wire, connect the appropriate connector pins, usually red & white in the diagram, to bolts placed thru holes in the handle. The bolts make a convenient place to connect alligator clips.

It took about a half hour to put together and cost less than $15.

 

[Topzide]

That won't handle that much amperage for long. The wires in the truck aren't that big. Need the amperage to push the power through the different connectors in the harness.
Easier to do it right and wire in a heavier wire with an Anderson type power connector. Wire like you were using a small winch on the back of your truck.
That adapter that you made, would work nice to check wiring or much lighter loads, IMO.

 

[LittleBill21]

That won't handle that much amperage for long. The wires in the truck aren't that big. Need the amperage to push the power through the different connectors in the harness.
Easier to do it right and wire in a heavier wire with an Anderson type power connector. Wire like you were using a small winch on the back of your truck.
That adapter that you made, would work nice to check wiring or much lighter loads, IMO.

have to agree, that's a very long run, generally with small wire, and on new trucks may be integrated into a expensive module, i would use it for very light loads.

 

[bdhsfz6]

It isn't intended to jump start another vehicle, just provide 20 to 40 amps (depending on the vehicle) for lighter loads like tools, chargers etc.

The circuit has a 40 amp fuse on my pickup and is rated for that according to the manual.

 

[Topzide]

For example, 30 amps in a vehicle would require 12 ga stranded wire, maybe 14 ga if they're pushing the limits. I know that electric brakes have 12 ga wire to handle that load. You have to remember that they won't wire vehicles with the best and heaviest wire they can. Things go out to the best bid. Most wires in today's vehicles is 16 ga and smaller.
Not trying to say it'll jump-start a vehicle, but putting a 20 - 40 amp load on that connector isn't recommended either! Manuals can be confusing with all the trim and options level available.

 

[ning]

12V at 30 amps on 12ga over 15' gets you 10.19V at the end - 15% voltage drop.
We're going to need more copper.
And yes, 15 feet.
On my truck ('97 F350 CC LB) it took over 20' to run from the left side battery to the back bumper (you can't exactly go in a straight line)

 

[Racer4]

Great idea. Thanks for posting. I could use this for my R/C battery charger!

 

[WranglerX]

THE 12 volt lead in the 7 way RV plug is primarily for charging battery in trailer breakaway brake systems or charge a battery to run some simple utility lighting in things like horse trailers and box trailers....

 

[chim]

On a somewhat related application - I have a dual purpose set of jumpers made of 2/0 welding cable. A lot heavier than most standard jumpers, but they do handle the loads. First to power a winch and then as jumper cables. There's a 350A Anderson connector under the hood on both the tractor and the Trailblazer. Then a 25' set of extension cables with an Anderson connector at each end. Then another 6' long set with an Anderson connector at one end and Visegrips on the other.

There's more than enough length to reach the rear end of the Trailblazer for the receiver-mounted winch. Still didn't get around to welding the front receiver tube in, but when that happens the winch tail can plug into the vehicle tail without using the extension. Tractor is set up like that now.

As jumpers, the vehicle tail plus the 6 footer with the Visegrips was able to reach twice for jumping another vehicle when access was available. The tails plus the 25' extension are long enough to park behind the dead vehicle and still reach its battery. Or I could reach the front of the tractor if it dies in the shed and simply plug it into the Trailblazer without even using the Visegrips.

The connectors only go together one way. It's nice having everything automatically being polarity matched right up to the Visegrips. Never had jumpers with a connection like the Visegrips provide.

 

[bdhsfz6]

The above trailer wiring harness alligator clip adapter is really meant to replace the cigarette lighter socket which neither of my vehicles have. It isn't meant for heavy amperage equipment. The circuits in my vehicles are fused at 40A.

I use it mainly to power my Viair 400P air compressor, to connect a battery charger / maintainer, a small portable winch, and a couple of other low amperage devices.

Sure, I could have wired a separate connector to my vehicles, but that would mean wiring a mating connector to each piece of equipment I use, as well as any equipment I buy in the future. Alligator clips are fairly "standard" and all my gear uses them. This simple adapter saves all the work.