Compressor Wiring

[Antichrist]

Yes, use a relay. 50amp relays aren't uncommon.
Having the switch close ground is safer if there's any chance of the wire from the switch to the relay abrading. If it's well protected there's little additional risk.

 

[Sheep Shagger]

Another question, this time regarding the switch.
I want to leave the switch at the compressor ON and turn it on/off via a switch on the dash. I could use recommendations on how to do this. I'm assuming I should use a relay. Do I need a special relay for amperage this high? What about wiring the switch to close ground? I've heard this may be safer but have never done it.
Thoughts?

Yes you should use a high power relay. If you want to be safe, I'd put it under the hood next to the battery and fuse, not next to the compressor in the cargo area.
BTW, Quick look at the spec on that, it states 1HP peak. 1HP=746 Watts. 746 Watts @ 12V is 62 amps. So according to the spec, running that will peak at 60amps, the 30A rating is probably just average running. So personally I'd be looking at a 60 amp relay & fuse and wiring.

 

[fishEH]

Sounds good. Looks like I'll be getting some 2ga welding cable for a good price. I'll pair that with a high amp relay.
Question though. The wire coming out of the compressor is maybe 6ga. Is that going to be an issue?

 

[slomatt]

I helped a friend mount a Puma on a 1st gen Xterra. We mounted the compressor under the rear bumper, the tank between the rails, and the pressure switch and adjustor inside the engine bay. From what I remember we used 4 awg for the power wires and it has held up fine during ~5 years of use. The most difficult part of the project was finding the proper fittings to remote mount the compressor and the tank. To handle the high heat we ended up using solid copper line from the compressor to the tank which required the use of a flaring tool.

Currently I have a MV50 mounted in my 4Runner, but every once and I while I eyeball my Puma thinking of places I could install it. The Puma is MUCH more powerful than the MV50, but of course it is a lot bigger and harder to fit in the truck.

- Matt

 

[Sheep Shagger]

Sounds good. Looks like I'll be getting some 2ga welding cable for a good price. I'll pair that with a high amp relay.
Question though. The wire coming out of the compressor is maybe 6ga. Is that going to be an issue?

It's all in the run/length or wire as that's where the resistance comes into play. From the below URL, it looks like 6ga at 60amps is good for about 35ft of wire.
http://www.rallylights.com/hella/SensibleWiring.aspx

 

[fishEH]

Picked up the 2ga wire tonight. It's actually Warn winch wire so should be fine. The more I think about it I think I want to run the 2ga to an aux fuse block in the cargo area. Then run the compressor, some cargo area LED's, and an inverter off that.
Here's a pic of the compressor installed. Just need to plumb and wire it......still.

 

[Antichrist]

It's all in the run/length or wire as that's where the resistance comes into play. From the below URL, it looks like 6ga at 60amps is good for about 35ft of wire.
http://www.rallylights.com/hella/SensibleWiring.aspx

That chart is way off for optimal wiring. 35' @ 60A should be #2 to keep volt drop under 1/2 volt. Important for optimal light brightness and for motor life if it's a motor driven load.

Picked up the 2ga wire tonight. It's actually Warn winch wire so should be fine. The more I think about it I think I want to run the 2ga to an aux fuse block in the cargo area. Then run the compressor, some cargo area LED's, and an inverter off that.

You'll be good for up to a 150A load, assuming a 15' run.

 

[TheAlmightySam]

The more I think about it I think I want to run the 2ga to an aux fuse block in the cargo area. Then run the compressor, some cargo area LED's, and an inverter off that.

If I may make a recommendation, Blue Sea Systems fuse blocks are AWESOME. They come in a variety of configurations, and the ones I'm familiar with can handle a 100A simultaneous load, more than enough to run your OBA, an inverter, and some lights.

 

[fishEH]

Whew its been a while. Finall got my locker and HD axles installed so this and the switches are the last piece of the puzzle.
Dilema:
I have 2GA from the + battery to compresor, about 16'. I also have about 2' of 2GA from the compressor to the frame for ground. everything works great. Except my Ground cable is about 6" too short to mount everything ideally.
Question:
For the short length of ground, about 30", can I use some 4GA welding cable I have? Thanks.

 

[LandCruiserPhil]

Do you have a ground from your battery to frame? Most vehicle battery grounds go to the engine block.

 

[fishEH]

Do you have a ground from your battery to frame? Most vehicle battery grounds go to the engine block.

Yeah, there's a lead from the negative terminal to the frame.
Soooo, think the 4GA will suffice for that 30"?

 

[G_fresh]

4AWG is fine for 30" carrying 60A. Less than 50mV (5/100 of a Volt) drop. And, less than a 35 degree Celsius rise in temperature of the wire...

All this assumes Wikipedia's AWG table is correct!

 

[LandCruiserPhil]

No problem at 30" given most jumper cable are #6 or #8 at best. I just test voltage and amps on a friends PUMA install using #6 at ~12' never dropped below 12 volts at full load of 42A. I do find a throttle lock on my set up at ~1200 rpm helps, cutting 15sec per tire off refilling time.

You will love the PUMA

 

[fishEH]

Its done, finally!! Thanks for the help guys. I made a push last night and got everything hooked up.
Quite a disaster!

Compressor switch on the left, pneumatic switch for air locker on the right. More on that later.

Blue Sea fuse block, relay and large separate fuse holder for the compressor. Looks messier in the pic than it is. Everything gets covered behind some trim.

And everything put back together.

Everything is hooked up. Compressor runs great. Locker works. Though its so quite i had to raise the back end and spin the wheels to make sure it was working.
The only snafu was the pneumatic switch for the locker. It has air line two ports on one side and one out the back. I thought the ports mounted face down and carved out the foam in the dash under the switch to accommodate the fittings. Turns out the ports face up, so when the locker is ON the toggle is UP. So for now the compressor and locker switches are down=on, up=off. That will get changed when I get some more time though.

 

[fishEH]

Well it's been a year and a half and the Puma is still kicking butt. Haven't had one problem with it either for airing tires or lockers.
I swapped out my rear ARB for an Ashcroft and got one for the front at well.
New switch pics.