I’ve pieced together my horns and got myself two tanks and a compressor and am unsure which route to go. I picked up an air tank off of a semi from a semi junkyard, the tank measures 9in. around, and 28in. long, 26 at the end seams. Thats probably what a 5 gallon tank??
The air compressor I have, I don’t know much about. The label says 840 Air Compressor, specs include Max Pressure: 110ps. Max Duty Cycle: 25%. Flow: 2.03 CFM. Would this compressor work alright for that big of a tank?
I also have the same tank from that kit which includes a pressure switch. Should I just run that tank with the compressor for now? If you guys think I’d need a bigger compressor for my big tank, I’ll just forget about that tank and run the smaller one at 110psi.
Really need to know what horns your running and at what psi they should run? At those measurements thats atleast a 7.5 maybe 8.0 gallon tank…That little compressor will work over time to fill that big of a tank.I would run 2 compressors,like 2 viair 380’s or 2 viair 444’s and run atleast 150psi…Just my opinion!
I planned on running the compressor to a switch, that way I could run it whenever I felt like running it, that way I don’t have it running all the time. I still need a pressure switch…if I was to get one to run up to 150 psi…will that air compressor still work alright since it says 110 on it?
If the compressor is rated at 110psi it will not push 150psi…And after seeing what horns your using,you dont need a 8-9gal tank for those horns,that compressor your asking about will struggle to fill that tank.Go with a much smaller tank or a much better compressor.A 2-4gal tank is plenty for those horns…
Thanks, I’ll just hang onto my bigger tank for now until I can find a bigger air compressor down the road and use the smaller tank that I have which is the same tank as the one I posted in my first post.
Now, my question is, how do I wire the compressor into the pressure switch in this tank. Its got two small terminals coming off of the pressure switch.
If you just have the cheap little pressure switch that just has 2 prongs on top of it you dont want to run power thru it,you want to use it as a ground to trigger the compressor.I will try and explain…You will run a power wire from your battery to the power wire of the compressor,but use a 50amp fuse inline with it.Then go to your pressure switch and run a wire off one prong to a good ground on your frame,then run the ground wire of the compressor to the other prong of the pressure switch.When the pressure switch kicks on it will complete the ground circuit and cause the compressor to come on.Most people dont know it can be done this way,but it saves your pressure switch and relays from going bad.By doing it this way,you prevent running high amps thru your switch and do not need a relay.BUT make sure you dont have any air leaks or the compressor will come on everytime your pressure drops below your pressure switch rating.OR spend a couple dollars and get the pressure switch/relay all in one from hornblasters.com its just as simple to wire up and it will only let the compressor come on when your ignition is on.
I want to put a switch inside the cab and want to run a small LED indicator light for when the compressor is running.
If I was to achieve a key on power with a relay…I’d find a key on accessory source from the fuse box under the hood, run that to the relay. Ground coming off the relay. Power wire from battery going into relay and a wiring going to the switch. Would this be somewhat correct. I’ve messed with relays once maybe twice before.
Your figure shows the compressor’s motor power circuit flowing thru the pressure switch. Only do this if the pressure switch is rated for the current draw of the motor. In this situation, it doesn’t matter if the pressure switch is located in the positive or negative side of the compressor - in a series circuit current is the same throughout the circuit. So all components in that circuit (fuse, switch, pressure switch, motor) will be subject to the same current flow.
A better circuit would use a relay to power the compressor and your switch and pressure switch to power the relay. This way the pressure switch / switch are only subjected to a few mA of current flow required to pickup the relay and the beefier relay contact can better deal with the large current draw of the motor.
Don’t overlook wire guage either when it comes to the power for the compressor. Too many people only worry about the ampacity of the conductor versus the current draw of the motor. This is important, but the voltage drop due to line resistance is just as important. It doesn’t take a lot of resistance over the length of the wire to drop the voltage. And, when dealing with only 12-14 V there isn’t much room for loosing any volts.
Battery positive goes to pin 30 (use a fuse near the battery - sized for the compressor)
Pin 87 goes to the compressor positive
Key-on to small fuse to toggle to pressure switch to pin 86
pin 85 goes to ground
As he mentioned you can also put the pressure switch on the pin 85 ground like your diagram shows.
