Truck, on Board Air Compresor & Tank,




I had wanted to build an on-board air compressor/tank system for my truck. Typical uses would be to fill up bike tires, trailer tires, and occasional vehicle tire when camping, or driving off road.  Retail kit systems are over priced, under built, and not the right configuration for my space constraints.  I decided to build my own system, piecing it together from new and used parts. 

I started with a used, non working, 3gal 110V air compressor that I found on CraigsList for $20. This had everything I needed; like a pressure relief valve, pressure switch, drain valve, check valve, and was the right shape configuration I was looking for. (long and skinny)

Step 1:

I stripped the dead motor and compressor head from the tank, and prepared to mate a 12V DC compressor motor to the tank. This 12V DC motor is from Harbor Freight Tools. It is their HD 150PSI unit, which I modified to hard mount to the tank, and plumb its air outlet to the tank.

Step 2:

Step 3:

I reconfigured the pressure switch to trigger the motor to turn off at 110psi (formerly +125psi) This is to reduce load on the compressor motor and keep it from overheating, and hopefully decrease its failure rate. I also completly removed the pressure regulator.

Once the 12V DC compressor was mounted and attached to the tank. I mounted the whole assembly to the truck bed. The tank has integrated rubber feet, which I used as part of the attach points. Now the tank is semi 'rubber mounted' to the truck bed.
I ran a fused 12AWG wire pair directly from the battery to the compressor. But I also ran another pair of wires from the cab, to the compressor to be used as remote ON/OFF from inside the cab. The remote switch powers an automotive style relay, which allows the current to the DC motor of the compressor. See the full electrical and air line schematic below. The schematic shows additional equipment that supports air horns, but I do not cover them in this instructable.

Step 4:

Step 5:

Remote pressure gauge, and Compressor ON indicator LED.



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    9 Discussions


    3 years ago

    How well does it work? I was planning to do the same thing, but Harbor Freight says not to start the compressor under load


    4 years ago

    how did you configure the 120v pressure switch to operate on 12v

    1 reply

    Reply 3 years ago on Introduction

    A switch's "rating" is usually the maximum it can take, because it's basically just 2 pieces of metal coming together or apart. There are some caveats to this that deal with current, wattage, etc, and some having to do with big, heavy high-voltage stuff but generally this works.

    If you're talking about a relay though, that's something completely different.


    4 years ago

    love this setup! just ordered the same pump from harbour freight. would love to see another instructable from you


    7 years ago on Introduction

    I recently purchased a motorhome and I am going to add a compressor like this to it. I think I will have schrader valves at each of the wheel wells, and also provide air for a set of 42" long buell airhorns. This should be a nice touch.


    7 years ago on Introduction

    I really like your idea of sourcing different parts that aren't really designed to work together to acomplish your goal. I'm looking to do something very similar with my Jeep, although I'm using a 110v portable Craftsman compressor, powered through an inverter. The Craftsman compressor gets me a 1.5 gal. tank, 150 max psi. compressor, with a tank pressure gauge, an off/auto switch and an adjustable output pressure, with gauge, and a 200psi blow-off valve, 25' coil hose, and tire chuck for $100. I have a four gauge wire ran to a fused distribution block that is designed to power two amplifiers already ran to the back of my Jeep. One "side" of the distribution block is indeed being used to power a small amplifier for one subwoofer. I'm hoping that the other "side" will be suficent to power an invertor that I've found NewInBox at a local second hand store for $80. I'm thinking that I should be able to leave the switch set to auto on the compressor, and use a solenoid to switch power on and off from the driver's seat for the invertor. I've already purchased a two way tee-fitting and two quick connects; that way I should have one air out put for airing up tires, and another for plumbing for an air-locker in my Jeep at some point down the road. As a by-product of running the compressor off of an invertor I will now have a 110v source in the back of my Jeep when camping etc..


    7 years ago on Step 5

    Nice! I may have to do something similar. Thanks for posting this.