On board air on the cheap

[zopperman]

SKIP TO THE LAST PAGE, MOD COMPLETE.

I'm planning on doing this: 4x4Wire - Portable Onboard Air Installation

in the coming days (minus the tank), mounting the compressor in the engine bay and mounting a fitting somewhere.

I'm confused about how to wire it with the relay.

as i understand it:

pin 30: direct to battery with ring terminal on + with 10 AWG wire
pin 86: ground on the body 10 AWG
pin 86: switch, then flip it around and also go back to battery with ring terminal?
pin 87: power to compressor with 10 AWG

 

[gaterose]

That looks like a cool idea. Do you plan to hard mount it or put it in a plastic shipping tote?

Should be 85 (not 86) to one side of the pressure switch. The other side of the pressure switch should go to a switch you have mounted in the cab that turns your onboard air system on and off. That switch will have a plus/negative from the battery/body respectively.

I'd probably wire the in-cab switch to an ACC positive in case you leave the switch on after wheeling so the compressor doesn't run your battery down overnight.

 

[gaterose]

Use this diagram and replace "attach to factory backup wire" with "attach to pressure switch" and "KC Backup Lights" with "air compressor"

and instead of attaching the blue wire to 87 on the relay, attach it to the other side of the pressure switch.

 

[zopperman]

That looks like a cool idea. Do you plan to hard mount it or put it in a plastic shipping tote?

Should be 85 (not 86) to one side of the pressure switch. The other side of the pressure switch should go to a switch you have mounted in the cab that turns your onboard air system on and off. That switch will have a plus/negative from the battery/body respectively.

I'd probably wire the in-cab switch to an ACC positive in case you leave the switch on after wheeling so the compressor doesn't run your battery down overnight.

Use this diagram and replace "attach to factory backup wire" with "attach to pressure switch" and "KC Backup Lights" with "air compressor"

and instead of attaching the blue wire to 87 on the relay, attach it to the other side of the pressure switch.

Thanks

Nah, I'm going to paint it or plastidip it to protect it from the elements and bolt it to the body, or U bolt it in place.

I wasn't actually going to use a pressure switch since I don't have the tank, though I could be persuaded if you have a good idea for a mounting spot? I'd put the tank where the spare is... but i need my spare and I like all the storage space I can get.

As for the in-cab switch, I'm gonna use a daystar switch. Any ideas on which acc wire to tap that is close to the switch panel on the left of the steering wheel?

i accidentally wrote 86 twice. As i'm seeing, 85 would go to my switch and then to a + source and 85 would go to ground and 87 would be the power for the compressor (wired to the compressor with 10 AWG) right?

 

[gaterose]

I'd mount it behind one of the bumpers or in the cargo area.

I'm not sure it's worth going to this much trouble just to mount an air compressor with no tank though.

I guess you'll save a couple steps connecting the battery and pulling hose instead of a compressor to all 4 corners, but carrying the extra hose will take up the space gained by not just carrying the compressor in the cargo area and taking it from tire to tire. The wire is also much more flexible than air hose so it would be a little easier in some senses to move the compressor from tire to tire than just a coiled air hose.

edit - a real baller would build a roll cage and tube bumpers then use that for the air tank... c'mon don't cheap out on us man.

 

[zopperman]

I'd mount it behind one of the bumpers or in the cargo area.

I'm not sure it's worth going to this much trouble just to mount an air compressor with no tank though.

I guess you'll save a couple steps connecting the battery and pulling hose instead of a compressor to all 4 corners, but carrying the extra hose will take up the space gained by not just carrying the compressor in the cargo area and taking it from tire to tire. The wire is also much more flexible than air hose so it would be a little easier in some senses to move the compressor from tire to tire than just a coiled air hose.

edit - a real baller would build a roll cage and tube bumpers then use that for the air tank... c'mon don't cheap out on us man.

You think? I could easily be persuaded, it just seemed like extra effort since I'm just using it to fill my tires...?

I figured with 50 feet of hose it'll be pretty easy to just A) throw it under the seat never to be seen again B) drag the hose and not pop the hood and hook up the compressor etc.

 

[gaterose]

You think? I could easily be persuaded, it just seemed like extra effort since I'm just using it to fill my tires...?

I figured with 50 feet of hose it'll be pretty easy to just A) throw it under the seat never to be seen again B) drag the hose and not pop the hood and hook up the compressor etc.

Meh, I guess you're right. I guess I just want a tank.

 

[zopperman]

Meh, I guess you're right. I guess I just want a tank.

fair enough. If i can find a cheap one maybe ill throw it in but it looks like most are like 60+.

Any insight to my other wiring questions/am i gonna blow stuff up? Which +/- should I tap in the dash? I used up my allowance for my cig lighters. Maybe the +for the AC115? I don't know which wires those would be. I need the ground for the LED in the switch

 

[chitown40]

I built a pretty nifty compressor driven OBA system on my old FZJ80 back in the day when I went wheeling instead of working 2 jobs and changing diapers.

Some thoughts:

If you are not going to put in a tank, there is really no reason to permanently mount it in the vehicle. Tank, pressure switch, manifold, air line, etc. can be had pretty inexpensively if you shop it around and pick up some gently used parts on eBay.

Instead of permanently mounting the compressor, spend your time and money and run a fused or breakered 10GA wire from your battery or AUX fuse box to a nice waterproof connector (something rated for high amp marine use comes to mind). Wire the compressor with the other end of the connector. Make sure you wire the vehicle side of the wiring to where you want the compressor to sit when you go off pavement. Then just use your heavy duty plug/connector and save going in under the hood when you need to use it.

I would do the above, but also try and find a slim air tank to go along the frame rail or somewhere in the undercarriage and plum that in the vehicle as well. You'll appreciate the extra capacity. Be creative -- you could use PVC or black pipe to make an air reservoir. You can source an old truck air brake tank. They come in all shapes and sizes. PVC is generally not recommended, but if you only put it under pressure when you need it and not constantly, it will hold enough air to speed things up when you're using the compressor and shouldn't crack or break.

 

[gshadow325]

I'm planning on doing this: 4x4Wire - Portable Onboard Air Installation

in the coming days (minus the tank), mounting the compressor in the engine bay and mounting a fitting somewhere.

I'm confused about how to wire it with the relay.

as i understand it:

pin 30: direct to battery with ring terminal on + with 10 AWG wire
pin 86: ground on the body 10 AWG
pin 86: switch, then flip it around and also go back to battery with ring terminal?
pin 87: power to compressor with 10 AWG

That looks like a cool idea. Do you plan to hard mount it or put it in a plastic shipping tote?

Should be 85 (not 86) to one side of the pressure switch. The other side of the pressure switch should go to a switch you have mounted in the cab that turns your onboard air system on and off. That switch will have a plus/negative from the battery/body respectively.

I'd probably wire the in-cab switch to an ACC positive in case you leave the switch on after wheeling so the compressor doesn't run your battery down overnight.

OK LETS SET THING STRAIGHT ABOUT WIRING!! I am getting scared with the correct and misinformation being passed out.

30 is your input
87 is your output
86 is your positive trigger
85 is your negative trigger

all conditions need to be met on 30, 85 and 86 in order to have anything come OUT of 87. Using that principle, lets apply it to your situation.

If you want it to turn on and off with the car and i suggest using negative to trigger the relay on.
-30 to constant fused 12volt
-87 out to compressor
-86 ignition trigger from steering column
-85 to switch then from stwitch to ground

If you dont want it turning on and off with your car and on at all times, do the following

-30 and 86 wire to constant 12 volt
-87 out to compressor
-85 to swtich then from switch to ground

If you are using a pressure switch all you do is add in the switch in between 87 and the compressor.

Pressure switch uses a 12volt feed in and 12 volt output. so 87 will go to any post on pressure switch then the other side will go to 12v side of compressor, on the compressor the other wire will be to ground. when pressure reaches what ever switch is set for, it will turn off power going to the compressor.

If you noticed, i always say use a ground as a switch opposed to using 12volt or 86 side as a switch because, you dont want current running thru the switch. current running thru switch can cause it to melt and fail. using a ground it will never happen.


Zack, you need to look at my truck before you perform this so called MOD. You will see how a 1 gallon tank, compressor and train horns will fit under the hood of a 4gen 4runner LoL.

 

[gaterose]

OK LETS SET THING STRAIGHT ABOUT WIRING!! I am getting scared with the correct and misinformation being passed out.

Whoa, let's calm down with the exclamation and capitalization.... There's no misinformation in my post, everything I said will work correctly unless the guys at KC have been wiring up lights wrong for 43 years and all of the accessories on my truck are only working in my imagination.

All switches have a rating for a certain amount of current to pass through, most I've seen are 20A, much less than will be used to trigger the relay, as I described. There should also be a fuse between the positive source and the switch (as shown in the diagram I provided) to keep from overloading the switch.

It sounds like the way you have it described that the entire current of the system is being passed through the switch, just that the switch is on the ground side instead of the positive side.

 

[gshadow325]

Use this diagram and replace "attach to factory backup wire" with "attach to pressure switch" and "KC Backup Lights" with "air compressor"

and instead of attaching the blue wire to 87 on the relay, attach it to the other side of the pressure switch.

Whoa, let's calm down with the exclamation and capitalization.... There's no misinformation in my post, everything I said will work correctly unless the guys at KC have been wiring up lights wrong for 43 years and all of the accessories on my truck are only working in my imagination.

All switches have a rating for a certain amount of current to pass through, most I've seen are 20A, much less than will be used to trigger the relay, as I described. There should also be a fuse between the positive source and the switch (as shown in the diagram I provided) to keep from overloading the switch.

It sounds like the way you have it described that the entire current of the system is being passed through the switch, just that the switch is on the ground side instead of the positive side.

Just because they work does not mean they are wired in the best fashion.

By saying "just that the switch is on the ground side" and trying to play down the importance of using a negative switch.

Sharing information is the key here. Sharing proper information is even more important.

Whatever pissing match you want to get into, I don't want any part of it. I live and breathe 12 volt all day long, so I have nothing to prove. Just give you a experienced experts advice, but hey what do I know. Lol

 

[gaterose]

Just because they work does not mean they are wired in the best fashion.

By saying "just that the switch is on the ground side" and trying to play down the importance of using a negative switch.

Sharing information is the key here. Sharing proper information is even more important.

Whatever pissing match you want to get into, I don't want any part of it. I live and breathe 12 volt all day long, so I have nothing to prove. Just give you a experienced experts advice, but hey what do I know. Lol

I'm not trying to get into a pissing match, you're the one who came out basically insulting me screaming about "scary misinformation."

If sharing information is the important thing here, perhaps you should try to do it in a less insulting and condescending way.

edit- also why is a negative switch important? All you say is that it's important, if it's attached directly to the relay, which is pulling 30A then my understanding is that 30A also flows through the negative side, and therefore the switch in the method you've described whereas my method puts no load on the switch, the switch is only a trigger and would be fine with a 3A fuse on it.

 

[sluggercz]

Whatever pissing match you want to get into, I don't want any part of it. I live and breathe 12 volt all day long, so I have nothing to prove. Just give you a experienced experts advice, but hey what do I know. Lol

Haha you need to calm down buddy
[MENTION=55855]zopperman[/MENTION] That OBA setup looks pretty good, cost effective as well. Only thing I'd want to know is the duty cycle of the air compressor, if it's less than 50% you might want an air tank somewhere in your setup.

I just found an old CO2 tank in our garage, so I'll probably rig up a OBA solution with a regulator, air hose, and chuck with pressure gauge - the whole setup shouldn't cost me more than $70.00

 

[zopperman]

OK LETS SET THING STRAIGHT ABOUT WIRING!! I am getting scared with the correct and misinformation being passed out.

30 is your input
87 is your output
86 is your positive trigger
85 is your negative trigger

all conditions need to be met on 30, 85 and 86 in order to have anything come OUT of 87. Using that principle, lets apply it to your situation.

If you want it to turn on and off with the car and i suggest using negative to trigger the relay on.
-30 to constant fused 12volt
-87 out to compressor
-86 ignition trigger from steering column
-85 to switch then from stwitch to ground

If you dont want it turning on and off with your car and on at all times, do the following

-30 and 86 wire to constant 12 volt
-87 out to compressor
-85 to swtich then from switch to ground

If you are using a pressure switch all you do is add in the switch in between 87 and the compressor.

Pressure switch uses a 12volt feed in and 12 volt output. so 87 will go to any post on pressure switch then the other side will go to 12v side of compressor, on the compressor the other wire will be to ground. when pressure reaches what ever switch is set for, it will turn off power going to the compressor.

If you noticed, i always say use a ground as a switch opposed to using 12volt or 86 side as a switch because, you dont want current running thru the switch. current running thru switch can cause it to melt and fail. using a ground it will never happen.


Zack, you need to look at my truck before you perform this so called MOD. You will see how a 1 gallon tank, compressor and train horns will fit under the hood of a 4gen 4runner LoL.

I'd love to see how you set it up. I'm around tomorrow AM if you'll be at the shop, shoot me a PM. Or post some pics here

Whoa, let's calm down with the exclamation and capitalization.... There's no misinformation in my post, everything I said will work correctly unless the guys at KC have been wiring up lights wrong for 43 years and all of the accessories on my truck are only working in my imagination.

All switches have a rating for a certain amount of current to pass through, most I've seen are 20A, much less than will be used to trigger the relay, as I described. There should also be a fuse between the positive source and the switch (as shown in the diagram I provided) to keep from overloading the switch.

It sounds like the way you have it described that the entire current of the system is being passed through the switch, just that the switch is on the ground side instead of the positive side.

This is what I thought - the current would never exceed 20 amps (switch rating) just to trigger the relay, right? So I could just do that with like 14 AWG wire?

Just because they work does not mean they are wired in the best fashion.

By saying "just that the switch is on the ground side" and trying to play down the importance of using a negative switch.

Sharing information is the key here. Sharing proper information is even more important.

Whatever pissing match you want to get into, I don't want any part of it. I live and breathe 12 volt all day long, so I have nothing to prove. Just give you a experienced experts advice, but hey what do I know. Lol

I appreciate everyone's opinion and information

I'm not trying to get into a pissing match, you're the one who came out basically insulting me screaming about "scary misinformation."

If sharing information is the important thing here, perhaps you should try to do it in a less insulting and condescending way.

edit- also why is a negative switch important? All you say is that it's important, if it's attached directly to the relay, which is pulling 30A then my understanding is that 30A also flows through the negative side, and therefore the switch in the method you've described whereas my method puts no load on the switch, the switch is only a trigger and would be fine with a 3A fuse on it.

You edit is how I understood it to work. I was going to fuse that line with 5A

Haha you need to calm down buddy

[MENTION=55855]zopperman[/MENTION] That OBA setup looks pretty good, cost effective as well. Only thing I'd want to know is the duty cycle of the air compressor, if it's less than 50% you might want an air tank somewhere in your setup.

I just found an old CO2 tank in our garage, so I'll probably rig up a OBA solution with a regulator, air hose, and chuck with pressure gauge - the whole setup shouldn't cost me more than $70.00

Can you elaborate on how you would do this? I may be able to get a tank, i guess, but I'm not certain of how to put the fittings on and stuff. I've never owned a compressor let alone done anything with a tank.

I believe the compressor has an auto off switch to prevent it from over heating, i think they said it can be run for up to 20 mins without needing to cool down at 45 PSI.

 

[eddiebx]

OK LETS SET THING STRAIGHT ABOUT WIRING!! I am getting scared with the correct and misinformation being passed out.

30 is your input
87 is your output
86 is your positive trigger
85 is your negative trigger

...

Not to nit pick here but since you're trying to straighten out all the misinformation, I'd like to add a few points that might help other's when planning out their circuits.

85 and 86 are connected to the coil that actuates the relay once powered by the power source...you can hook positive and negative anyway you like, the simple magnetic coil inside won't know the difference. The only time polarity would matter is if the coil is protected with a diode (to dampen voltage spikes and what not); in this case you need to follow the pin layout according to what direction the particular manufacturer connected the diode across the coil.

30, 87 and 87a (on an SDPT) are not directional as you have suggested. 30 is the common terminal, 87 is the normally open, and 87a (if applicable) is the normally closed. Kind of self explanatory here, but basically when the coil is not energized 30 and 87 would not be connected (at the same time 30 and 87a would be connected); when the coil is energized 30 and 87 will be connected (at the same time 30 and 87a would not be connected).

I really don't see anything wrong with Zooperman's and Gatersose's circuit layout (besides the obvious mis-numbering of 86 twice, lol). Remember, there's more than one way to layout a circuit in order to achieve an end result. Just because you were taught differently does not mean someone else is wrong; nor does it mean you are wrong. The path you choose is mainly all just preference IMO

 

[eddiebx]

I'm planning on doing this: 4x4Wire - Portable Onboard Air Installation

in the coming days (minus the tank), mounting the compressor in the engine bay and mounting a fitting somewhere.

I'm confused about how to wire it with the relay.

as i understand it:

pin 30: direct to battery with ring terminal on + with 10 AWG wire
pin 86: ground on the body 10 AWG
pin 86: switch, then flip it around and also go back to battery with ring terminal?
pin 87: power to compressor with 10 AWG

:focus:

So out of curiosity...if you're planning to just use a cheap 25 dollar pump and no reserve tank, as that link suggests, what is the point of hard mounting it besides cool factor? Just my opinion here, but it seems rather pointless and maybe even a bit counter intuitive considering you could just throw the portable compressor in the trunk and plug it into the closest cigarette lighter outlet when airing up. That rolled up 50 ft air coil probably takes up more room than the entire compressor in the trunk, lol.

Are there any advantages that I am just not seeing? Not trying to knock on you here, just wondering

 

[zopperman]

:focus:

So out of curiosity...if you're planning to just use a cheap 25 dollar pump and no reserve tank, as that link suggests, what is the point of hard mounting it besides cool factor? Just my opinion here, but it seems rather pointless and maybe even a bit counter intuitive considering you could just throw the portable compressor in the trunk and plug it into the closest cigarette lighter outlet when airing up. That rolled up 50 ft air coil probably takes up more room than the entire compressor in the trunk, lol.

Are there any advantages that I am just not seeing? Not trying to knock on you here, just wondering

A) 60 dollars :rockthrow:
B) cool factor
C) has to clip to battery, would draw too much and blow cig lighter fuse
D) cool factor
E) fun project

and most of you guys are convincing me to get a small tank. I just can't seem to find one that can hold 80+ PSI and is only 2 gallons or so and will fit in my engine bay. or behind my bumper. I just can't find a tank. I looked around for old small fuel tanks but they're pricey too. On that link the guy claims he found one for 20 bucks that was 2 gallons.

 

[eddiebx]

A) 60 dollars :rockthrow:
B) cool factor
C) has to clip to battery, would draw too much and blow cig lighter fuse
D) cool factor
E) fun project

and most of you guys are convincing me to get a small tank. I just can't seem to find one that can hold 80+ PSI and is only 2 gallons or so and will fit in my engine bay. or behind my bumper. I just can't find a tank. I looked around for old small fuel tanks but they're pricey too. On that link the guy claims he found one for 20 bucks that was 2 gallons.

hey it was your link that said 25 bucks, lol. That's why I figured it was just a cheapo one that plugs into the cigarette lighter. But yeah if you need to clip it to the battery anyway, I see why you want to permanently mount it up

Have you looked into VIAIR cylidners? I think they have a real slim/long one that fits in tight places...I saw some of the guys over on the 5th gen forum using it.

EDIT: Here is a link to the one's I'm talking about: VIAIR Corporation - Air Tanks

Seems like they have a lot of flavors for the picking, good luck with the project!

 

[sluggercz]

Can you elaborate on how you would do this? I may be able to get a tank, i guess, but I'm not certain of how to put the fittings on and stuff. I've never owned a compressor let alone done anything with a tank.

I believe the compressor has an auto off switch to prevent it from over heating, i think they said it can be run for up to 20 mins without needing to cool down at 45 PSI.

I'm roughly doing the same thing as this thread: Build Your Own CO2 Tank System – High Quality & Lowest Cost

A CO2 tank is completely separate entity than a compressor with air tank, but like others have mentioned you should get a beefier compressor if you are going to hard mount it, as well as getting an air tank - could mount it in the engine bay(although it'd probably only be a 1gal so I'd advise against that), in the front bumper, or underneath the truck(if you've removed the spare tire there's plenty of space there).

Mine will look something like this when finished:

Portable, cost effective, and very simple - I'm more focused on its reliability and functionality rather than its looks.