Onboard Air...

Mcclegend said:

Can I ask what pressure your going to set your cut off switch to, max for the tank or something else?

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on at 80psi and off at about 120psi - the tank is plated to 145psi

wammers said:

A/C compressors are not suitable for compressing air. They work from a swash plate and rely on system pressure to return the pistons and need upper cylinder lubricant. That is why they will not engage with low system pressure or they will be destroyed.

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I'll have an oil drip going in and a coalescing filter before exit

huffhuff said:

I'll have an oil drip going in and a coalescing filter before exit

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Ok but how much air do you actually need on board to work lockers and the odd tyre inflation. There are lots of fairly cheap 12 volt units about that would do the job and be a lot less complicated to set up.

wammers said:

Ok but how much air do you actually need on board to work lockers and the odd tyre inflation. There are lots of fairly cheap 12 volt units about that would do the job and be a lot less complicated to set up.

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Ha, well I don't have lockers (yet) and rarely need to pump my tyres up. Also, I have a 12v heavy duty double pump already.

So why do I want to do it? Just because I do. You can honestly say you've never over-complicated something because a) you want to test yourself a bit or b) the simple fact you just can? I see it as a little project that keeps me busy in the few spare hours I have each week and it's only costing a few quid to do.

Each to there own I guess.

This is how mine fits. Used for the Rear diff lock and blowing tyres (and occasional airbeds) up.

From the pump head there is a 4 way manifold, so 1 inlet, 1 output to diff lock, via the short tube to the solenoid, 1 output direct to the air connector, one output to the pressure switch, 75 to 110 PSI (or thereabouts) The diff has a switch on the dash, which opens the solenoid, the air connector is piped straight in, so only needs coupling to let air flow. The pressure switch is fine for anything, tyres only go to about 30 psi ish, if not less when laning. The long black pipe goes to a bulkhead connector then straight to the diff lock.

OK, it looks a tad amateurish right now, but it works and I keep saying I'll tidy it up, like moving the swit earth and power somewhere less vulnerable, and maybe cover it or something ... one day ...

huffhuff said:

Thanks guys,

Are you saying I got the wrong sanden compressor and that all the other people that have successfully done this with what I thought was an a/c compressor are using something else?

Ta

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Look at it this way, yes it will work, it has been done by many guys here and I suspect all around the world, it is not the best solution because as said the compressor is purpose built for closed loop refrig systems, but it is neat and is driven by your engine, the chances of wearing the compressor completely out is slim, it will not have to run continuously, you have already thought about lubrication issues, some of my mates here run them without any and they seem to keep going.
If I didn't need the a/c so badly I'd use my compressor for a better volume of air than the ARB unit I have fitted.
So as you say, have a go it's worth it.

Paul that's the same compressor I've got can I ask how you wired in the cut off did you add a relay under the black cover to do with the 35amp draw. Would like todo this with mine, (not perment install) just want the out switch off, so I can use a standard tyre inflation and turn it off and on at the trigger rather than the back of the unit. I do rate the t max compressor, bought it off a review of the rugged guide and has served me well the few times I've used it.

Sorry if I'm hi jacking the thread

Can't tell you, sorry, I just left the on/off switch and relay in situ, and added a dash switch so I have to 'arm' the compressor, then use the dash switch to turn the diff on or off .. So long as there are no air leaks it stays quiet. The air fitting is surprisingly good, better than the ARB actually at not leaking! I use the stock Tmax air fitting, so it just runs constantly when I plug it in, which doesn't unduly bother me.

If I were to do it as you want it I'd add a solenoid inline with the air fitting and use the trigger to switch it on and off via the existing pressure switch, but keep the original on/off switch and just arm it when needed.

My idea is quick release male to one way valve then air horn pressure switch to quick release female, then can plug in normal tyre inflators. the shut off switch contacts just going to a relay that will cut the power if the line is pressursed and when I pull the trigger pressure drops and will start up again.


Where do your cables go to from the pressure switch

Mcclegend said:

My idea is quick release male to one way valve then air horn pressure switch to quick release female, then can plug in normal tyre inflators. the shut off switch contacts just going to a relay that will cut the power if the line is pressursed and when I pull the trigger pressure drops and will start up again.


Where do your cables go to from the pressure switch

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To the existing compressor switch. The switch arms the system, which will start the compressor to fill the manifold for a second or so till the pressure gauge turns it off. Then when I flick the dash switch it opens the solenoid to lock the ARB, the pressure sensor works to allow air through till the ARB has enough and shuts off again. If the ARB leaks then every once in a while you get a brrr as the compressor pumps the pressure back up again, depending on what the sensor reads. With the pump and pressure switch armed, the air fitting is always live, so anything plugged in doesn't need switching on, or if it has a normal air trigger it'll work on that trigger.

Cool, lots of scope to add a small tank and regulator if you want to run air tools.

Next addition will be a 6 port manifold for a front locker and maybe for a winch freespool .. and a tidy up of it all ..