Napa Air compressor

[GOOSE3]

I wanted a setup to air up my tires but didn't want to spend a ton, so I started a project. I want to get some ideas and thoughts from you guys. The compressor itself is pretty amazing and powerful, its a knockoff of all the others, but at $120 with coupon, I decided to get it. I cut out the factory board and based on a chat with a buddy and several online people decided to go this route. I will tap a pressure relief valve, located in the second pic, tap a 70-100 psi cutoff, 3rd pic, and also tapped the factory hose fitting with a quick release in 2nd pic. I also have a 200 amp relay to install as well as a 6 gauge jumper cable set that will connect to the system as the factory hoses and cable were a bit sketchy and got really hot when used. In the 4th pic I have the cables that I plan to use at first, then I will connect Anderson plugs and remove the cables, but for now, this will be the setup. I also made a flexzilla hose for 4 tires with a manifold. everything cost about $300ish so far. THe power from the motor is run using a smaller diameter wire, but to the battery I am using 6 ga, I plan to solder the connections for that, but need to figure out a way to keep the cables from being yanked around in that little area, not sure how to do that yet. I also have a 100amp Midi fuse for the cable.


Any thoughts or suggestions?

 

[RubiDukkie]

Not sure if this is the same mod you did, but posting it in case it helps someone else who wants to go that route.

Cleanest Pressure Switch Mod [Maxi Trac Compressor Review] - YouTube

 

[GOOSE3]

Mine is very similar to his, I am taking a few ideas from several people. I wanted the switch and pressure relief and no single video gave it all to me, so I took several ideas and used them.

Lock your Hubs 4WDing has a great video for those looking for a detailed install, he has in my opinion the best video, he does a great job of explaining and showing what he is doing. The Thumper Max video below is what I found that explained the most to me.

Here is where I am getting the cables when I am ready, I want to get the Anderson plug for the battery and compressor. Once I measure the exact lengths I will get them too.

Anderson plugs

Thumper Max

 

[majestek12]

Does the pump or your planned modifications include an unloader valve? These can significantly prolong the life of the pump and make the electrical operation more dependable.

Instead of a fuse, you may want to look into a 12 volt circuit breaker. This avoid you from having to carry spare fuses and can be Amazon'ed for $10-$20.

 

[GOOSE3]

I have not thought about an unloader valve, just the pressure relief valve because I wanted a way to relieve the pressure after using the compressor. What is the difference between pressure relief and unloader valves? I tapped for the relief valve and can swap them if needed.

I went with the inline fuse mainly because it was recommended by the guy I spoke to. I do have a 12 volt circuit breaker in my garage from another project, so if the fuse doesn't work, I will swap them out.

I should have talked to you before starting this, these are some great ideas, I am still playing with it, so I may very well change things up.

 

[majestek12]

An unloader, or dump, valve is tied to the operation of the pressure cut off switch. Combined with a check valve, it allows the compressor to pump up to the specified pressure, cut off, and then dump the pressure on the back/compressor side of the check valve. Properly implemented and plumbed, this allows the compressor to start up under no compression/load, which is profoundly easier on the mechanical components and significantly reduces the electrical inrush current. Think of it as riding a bicycle. If you start on a flat surface (no pressure in the compressor system) and pedal up the hill (to the top/pressure cutoff point) it's much less initially demanding than starting on the hill. Starting on the hill requires a lot more initial energy (electrical inrush current) from you, and you have to push exponentially harder on the mechanical parts (pedal, crank, crank bearings, etc.) to get the bike moving. This is why more expensive compressor systems that can't have unloaders, like those in home HVAC systems, often have startup delay timers. Otherwise they can be significantly damaged during power blips where they start running, cut off, then start up again under high head pressure.

Unloader valves can cause issues on oiled compressor systems as they let some of the lubricant out when unloading the air pressure. This this leads to a mess of oily film and ultimate depletion of compressor lubricant if not monitored. There's more to the subject and related system design, but I don't think it applies to you as I expect your compressor is oil-less.

A pressure relief valve is just a failsafe device that keeps the system from becoming over pressurized and potentially blowing up if the compressor doesn't turn off properly for some reason: it's much better to have the relief valve operate than exploding an air hose, air tank, or other system component. Relief valves can also be used as a mechanical dump valve, as most people do, but over time you'll find issues if used too often, such as poor sealing of the valve seat or eventual weakening of the relief spring and corresponding issues with maintaining proper system pressure. Even if you have a unloader valve, you still need a pressure relief valve for safety purposes, and it can still be handy for releasing system pressure when you're done.

 

[R3]

I have not thought about an unloader valve, just the pressure relief valve because I wanted a way to relieve the pressure after using the compressor. What is the difference between pressure relief and unloader valves? I tapped for the relief valve and can swap them if needed.

I went with the inline fuse mainly because it was recommended by the guy I spoke to. I do have a 12 volt circuit breaker in my garage from another project, so if the fuse doesn't work, I will swap them out.

I should have talked to you before starting this, these are some great ideas, I am still playing with it, so I may very well change things up.

If you use the Pressure relief valve as a way to blow off the built pressure, that will function the same way an unloader valve will. The idea is to start the compressor on low to no built pressure to prolong the electric motor life. In practice for the number of times you are using the pump once or twice a month or a few times a season it is a bit of over kill IMHO.

Circuit breaker is a great idea, and can be use for fast resets on the trail.

Something I found with these octopus air set ups is the rig needs to be level and balancing the air pressure in all 4 tires is somewhat problematic not on flat ground. I.e. rig leaning to right side the left side tires will pump up[ higher than the right. I use one of these on the Red Jeep for a year or so and finally moved to a single source inflate deflate approach. Take a bit longer but the tire pressures are more accurate.

 

[majestek12]

Well, the benefit of an unloader valve to system wear and tear is not related to the number of times you air up, the number of duty cycles is determined by the number of compressor starts and stops each time you do. R3 has a point though, I'll agree this may be overkill.

I didn't address the fuse versus circuit breaker topic, apologies. The benefit of the circuit breaker is that if it trips, you just reset it. If a fuse pops, you have to have a spare. High current midi fuses aren't exactly costly, but are relatively expensive for what they are, and you usually can't find them in retail parts stores when you're in a pinch. The cost of 12 volt circuit breakers has come down substantially in the past couple of years, but utilization compared to fuses hasn't followed. Back in the "big bass" days of car audio they used to cost upwards of $100, nowadays you can find them at pretty close too if not the same price point as high amperage fuses. Amazon has 12 volt 100 amp ones for $20, substantially less per unit if you buy a multi-pack.

 

[majestek12]

R3 has an interesting point on the octopus rigs. I honestly wouldn't have thought about the potential uneven pressurization. Really though, if using an octopus rig or single hose, tires should always be filled up on flat ground, otherwise pressure will change regardless once evenly loaded.

 

[R3]

Trail side.... the more compilated the more there is a chance for Murphy to apply is trade.... there is something to be said for K.I.S.S.

 

[majestek12]

Agreed, any failure is always more complicated when you're on the side of the trail. However, pressure cut offs with unloaders are engineered for industrial use and hundreds of thousands of duty cycles. If it fails, it can be bypassed with a little wiring. If your compressor fails, not so much.

Goose is obviously putting quite a bit of effort into his build, and it seems that it'll be installed relatively permanently on his Jeep. I don't know how much of his project will be specific to the particular air pump he's going with, or how much of this surrounding system would need to be retrofitted to swap in another pump. An unloader would certainly help prolong this compressor's life and avoid premature failure.

Was a thought, a possibility, I'm sure Goose will make the right decision for him.

 

[GOOSE3]

This compressor setup is mostly to get some easy access air that is cheaper than the other options. I had a cheap little compressor that took a long time to fill a tire, so this is a big upgrade. It will be stored in the back and pulled when needed, I am not opposed the the unloader option, I would just need to sort out space on the manifold, I will see how it all works and possibly pull the pressure relief and add the unloader. I am planning to stick it in an old ammo box, so I cant have too much sticking out. I also have a 100 amp circuit breaker that I can add when I swap cables. I am using the battery cable for now, but plan to get a set of cables with Anderson plugs so I can pop on in at that time. Thanks for the advice

 

[majestek12]

The unloader would need to be added in addition to the pressure relief, you need a pressure relief regardless for safety.

 

[zuke]

A couple minor notes to add, I've been playing with Maxi Trac clones for a few years now...

It's not Oil-less, it has oil in it from the start, and while it should go a while without adding any, it should have oil added every once in a while.

They are very popular to modify, and there are a lot of resources out there for info and ideas, There is a really active facebook group that has a good amount of info on it; https://www.facebook.com/groups/576631106662066/

It's a 10.2 cfm compressor, and if you don't modify it, running it against just one tire will noticeably heat it up quicker, as will going for higher pressures with them, I usually fill up two tires at a time to no more than 32psi, and try to account for any difference in vehicle position when doing it, IE, down hill tires together, and uphill together.

They get REALLY hot... If you mount it, make sure nothing around it is gonna get burnt/melted.

 

[majestek12]

Good point on the temps, Goose's idea of putting it in an ammo can may be helpful, with proper ventilation, but could also be detrimental. Sounds like some testing is needed!

 

[GOOSE3]

A couple minor notes to add, I've been playing with Maxi Trac clones for a few years now...

It's not Oil-less, it has oil in it from the start, and while it should go a while without adding any, it should have oil added every once in a while.

They are very popular to modify, and there are a lot of resources out there for info and ideas, There is a really active facebook group that has a good amount of info on it; https://www.facebook.com/groups/576631106662066/

It's a 10.2 cfm compressor, and if you don't modify it, running it against just one tire will noticeably heat it up quicker, as will going for higher pressures with them, I usually fill up two tires at a time to no more than 32psi, and try to account for any difference in vehicle position when doing it, IE, down hill tires together, and uphill together.

They get REALLY hot... If you mount it, make sure nothing around it is gonna get burnt/melted.

Great points, thank you. I have some synthetic grease that I have on now, it came with one piston lubed and one completely dry. I had not thought about the long term. Where else can it be oiled, I would be interested in learning about what you do.

 

[GOOSE3]

Good point on the temps, Goose's idea of putting it in an ammo can may be helpful, with proper ventilation, but could also be detrimental. Sounds like some testing is needed!

I only planned to store it in the can but hadn't thought about post-use heat dissipation, I may need to vent the box like you said, or leave it out to cool., You're right, more testing is needed!

 

[zuke]

Great points, thank you. I have some synthetic grease that I have on now, it came with one piston lubed and one completely dry. I had not thought about the long term. Where else can it be oiled, I would be interested in learning about what you do.

I just take the round plastic tops off the cylinder heads and put a squirt of air compressor tool oil into the intake port, then kinda slosh it around. I don't have a schedule, just do it when I think about it...

 

[zuke]

I only planned to store it in the can but hadn't thought about post-use heat dissipation, I may need to vent the box like you said, or leave it out to cool., You're right, more testing is needed!

I just leave it out to cool, Usually doing plenty of other things after airing up anyway, and 15 minutes seems to bring it down to a safe temp...

 

[GOOSE3]

ok, sweet, I used super lube to oil, but next time I will run some oil in there. Thank you for the tips and insight.