Onboard air in an R50.

[Rebelord]

You can do a spectra filter. Same thing half the cost.

 

Sent from my Moto X!

 

 

[stioc]

 

 

But being in government service for so long, I always go overkill and as efficient as possible.

 

...

[96Pathfinder4x4]

Just to be clear...I don't write policies. Navy Veteran and now contractor. The better I am at my job, the easier it becomes....being slightly neurotic helps also. I can get OCD at times. Sometimes it's a blessing....other times, it's a curse. I say the same thing about the inability to wear beer goggles.

[96Pathfinder4x4]

Air filter, MV50, and tire cover ordered over the weekend. Should have everything by this evening.

[96Pathfinder4x4]

Well...maybe this evening. I ship everything to my bud's house so the package doesn't get stolen. I'm swinging by tonight on my way home.

 

In my search, I've run across this. 10-32 psi low pressure switch. Opens at 10psi and closes at 32 psi. If I'm aired down to 15psi, then this is what I need..

http://www.zorotools.com/g/Pressure%20Switches/00018675/

 

I will have to use a relay for the power. It will probably take some bench testing since I may be the only one trying this (no hits on google)....and the 1/4" fitting might change the pressure. In theory it shouldn't...but...best to check. Any HVAC techs here? If I figure correctly, this switch is used to protect the motor if pressure falls below 10psi. In my case, it will do the opposite, turning it on at (or above) 10psi and cutting it off at 32psi, so a handy dandy relay may be needed. I have plenty of them lying around. 8)

 

After more thought, I'm going to add the removeable tank. I'm going to keep an eye out on Craigslist for a cheap air compressor...3 gallons seems common for oba systems. Just need to do some shopping at Home Depot and pick up some brass fittings.

[SilverPath]

I would look for a higher open/close pressure switch, the ARB unit comes with a 100/70 switch that seems to work very well. By compressing the air in your tank to only 35 PSI the volume is going to be cut down drastically. It will cause the compressor to be running continuously. With that having such a low cutoff is going to reduce your flow rate thus increasing your fill up times on your tires. I scanned in my copy of the wiring diagram that is included for the ARB compressor. It is pretty straight forward to follow and copy with your setup and some wire.

If you want, PM me your email addy and I can send you a copy of the entire installation manual for a reference.

[linkinpark]

That switch turns on if the pressure is 10 psi or lower. So if it is above that then it wont even turn on.

[96Pathfinder4x4]

That switch turns on if the pressure is 10 psi or lower. So if it is above that then it wont even turn on.

 

Using a relay, you can reverse that operation to function in the reverse. I will explain when I set up my test. At 10psi, there will be 12VDC to the compressor. At 32psi, the power will be removed.

 

I would look for a higher open/close pressure switch, the ARB unit comes with a 100/70 switch that seems to work very well.

 

This switch would be for the tire fill function. The switch for the tank will be matched to the rating of the tank I get.

 

You can do a spectra filter. Same thing half the cost.

 

Thanks for saving me $20!

 

Quest, as in Nissan Quest (minivan). The stock Nissan Quest alternator output is ~120a whereas the Pathfinder is ~90a.

 

I don't know if there are pressure switches that will shut off precisely at a typical tire-inflation pressure. They usually have a range, such as as off@105psi, on@85psi, so you will need both a pressure switch and a regulator for automatic operation.

As noted earlier in this thread, my version of the 4air system uses my sliders.

 

I'll look in to that alternator. Thanks!

*Quick disconnect (3) and air chuck added to shopping list*

 

I don't think I'll need a regulator...I don't plan on limiting the air flow. Is there another need for a regulator?

 

How do you drain the condensation from your sliders?

[linkinpark]

That's what the switch does normally. With those switches they turn off at the desired pressure. Which would make the switch open. Then the switch doesn't close the curcuit till 10 psi which turns on the pump till it once again reaches 32 psi and opens.

 

 

Now another idea would be to put a pressure regulator I. The line so that it never goes above the pressure you want. Does your pump have an automatic off at say 100 or so?

[96Pathfinder4x4]

I don't think so.

 

I would prefer that the switch cuts off the pump.

However a pressure regulator might be a nice addition as a safety feature in case the electrical switch fails....cheap insurance.

 

Switch description states that it opens at 10psi and closes at 32 psi. I will need a relay to switch the 12V on to the pump when the circuit is open and shut it off when it reaches 32. This is strictly for auto-filling 2 tires at a time. I will add a switch to bypass this functionality for when I'm in need to fill the tank, providing 12V to the cutoff switch that will cutoff the pump at the tank's pressure.

[96Pathfinder4x4]

Drew this up quickly. Here's my initial thoughts...it will help clarify things. ...I hope.

 

As I was uploading to photobucket, I was thinking and I might switch it to supply the grounds to the MV50, rather than the 12V. I need to research the Bosch relays current rating and what the MV50 current rating.

 

 

 

[XPLORx4]

You're overthinking the automatic inflation part.

 

With your 10-32psi switch, if you start up the compressor with no load, it will shut off at 32psi. Then you connect your tires, which will probably be aired down to something around 16-20psi. The compressor won't do anything, because the total pressure of the system (compressor and tires) is above 10psi. You would have to be aired down to BELOW 10psi to activate the compressor.

 

Plus, you may want to inflate your tires to higher than 32psi. I sometimes air up to 35-38psi at high altitude locations after wheeling to compensate for the tires being warm and the higher altitude.

 

Instead, I would opt for a high-pressure switch and a regulator, rather than the low-pressure switch you are considering. The compressor will cycle on/off at a high pressure, but the regulator will prevent the tires from being inflated more than what you set with the regulator.

[XPLORx4]

Also, your wiring diagram is wrong. You only need one relay:

30: +12vDC (batt)

87: +12vDC to compressor

85: ground (for the relay coil)

86: +12vDC (acc) + dash switch + 85-105psi pressure switch (replaces "valet switch" in below diagram)

 

http://www.mp3car.com/imagehosting/12527647e9129233622.bmp

 

Also, the pressure regulator is not electrical, it is pneumatic. It is plumbed in-line between the compressor air output and your tire air-up kit. If you are creating your own 2-air hose system, consider having the pressure regulator installed on a manifold on the 2-air hose, and the compressor having only a quick-connect fitting.

Edited December 11, 2013 by XPLORx4

[96Pathfinder4x4]

They're both cutoff switches. "regulator" inside the box is misleading.

I couldn't find a 35 psi switch, which is what I air my tires up to on the street. Looking at Jeep forums (and my buddy), they run 32 or less on the street.

 

I only need one relay if I don't use the 10-32 cutoff. It's only $10 and I love tinkering and making something that noone else has. (I once built a remote cutoff for a 50cc motorcycle using a $5 RC car 8) )

 

I will be picking up my pump tonight. Going to call around some HVAC supply places to see if I can get the air pressure switch locally so I can bench test next week.

[XPLORx4]

I'm not sure what you're trying to accomplish. It looks like you are trying to have 2 "modes": a high-pressure mode (SW1) and a low-pressure mode (SW2). You don't have a mode in which no power is being consumed ("OFF" mode).

 

I'm not sure what advantage there is to having the low-pressure switch vs a basic pressure regulator.

 

I assume the unlabeled switch on the far left is your main 'power' switch. The problem is, when that switch is off and pressure<10, then your compressor will run because it's on 87a of relay2. It will continue to cycle on/off as pressure fluctuates between 10-32psi.

 

Also, cutoff sw1 cannot be installed between battery power and the compressor, because of the amperage. I think the MV50 draws around 30 amps.

[96Pathfinder4x4]

I plan to run my tires at ~15psi...so I think it should still turn on after connecting the hoses....I should only loose 1 or 2 psi...it's all about the testing.

 

Yes. 2 functions to my dementia. Plan now, but plan for the future.

 

The amperage I noted in my initial post...I am not sure what the bosch relay is rated at....and just received the M50 today, so wasn't sure what the current draw was on it either. I didn't see anything on the Amazon description. Quick google search: A like this is rated for 30-40A, so if the MV50 max is 30A, I should be fine.

 

Good call. On the drawing I am missing a main power from the battery to the box that I will mount the relays inside. The switch will be in the cabin, so when I do have my tank, I will switch it on when we are close to camp. I plan for it to be a small removable plastic box, so if the electronics fail I can connect directly to the battery.

 

I will hook up the lines from the compressor to the tires prior to turning on the compressor. 3/8" hose, I'm not 100% certain that it will not drop below 15psi prior to the compressor coming on. If so, during testing, I will adjust as necessary. It may turn out that I can only run one tire at a time on auto. Even then, I will be able to let it run until it shuts off. I figure a pressure regulator set at 40 (to the tires) for redundancy failure. They tend to cutoff prior to their set...slowly letting through more air. The electric switch should cut it off at a similar point every time...and 32 is max for street use on a 32" MT.

[96Pathfinder4x4]

Guess I'm mounting it under the pathy or in the cargo compartment....no room under the hood.

[XPLORx4]

If you don't have the Bose system, or you used to but have since replaced your HU and done away with the Bose amp, you can probably fit the compressor into the cavity behind the left rear cargo panel.

[96Pathfinder4x4]

Gathering and pondering.

 

I now have a 15 gallon air tank and the compressor. Just need time to figure it all out.

[96Pathfinder4x4]

It's been a year and things are finally ramping up again for the PathGrinder!!! ©

 

I bought a house in July and have been busy remodelling. I haven't even had time to get the garage together...

Everything is still together and as I've left it. She's turned into a tow rig....towing a trailer to Lowe's and back.

 

Going to get started on the onboard air as my next project. I haven't even made it offroading since I moved. All in good time.