Here are some photos of my simple onboard air system utilizing a Viair 400H hardmount compressor:
The Compressor:
Electrical:
The factory 12 gauge wiring was replaced with a 12" 10 gauge leader and 2-pole connector.. Power for the compressor comes directly from the battery via a Blue Sea 5024 battery terminal fuse block and 10 gauge wire fused at 40 amps per Viair recommendations.
Factory Wiring
After rewiring with 10 gauge zipcord
Blue Sea Battery Terminal Fuse Block (P/N 5024)
Check Valve, Leader Hose and Hose Connections:
Plumbing at compressor head:
End of leader hose:
Rather than a step-by-step "How-To," here are the main points:
1. The mounting plate is a 4 3/4" x 12" piece of 11 gauge steel I found in the scrap bin of my local metal supply house ($1). I cut down an old neoprene mouse pad to cushion between the mounting plate and fender, but in hindsight it was probably unnecessary.
2. I purchased a 10 gauge 2-pole connector on Ebay. It came with 24" of wire between the connectors so I was able to cut it in half and wire one half in place of the smaller gauge wire provided by Viair from motor to switch. This allows me to simply unplug the compressor if the unit needs to be removed. [Be sure to pay attention to which way the plug is oriented. The "+" side should be protected and "-" side exposed on the battery side and the "+" side exposed and "-" side protected on the compressor side. That way there won't be a hot 12v + prong exposed when the compressor is disconnected from the battery.]
3. I wired the compressor with a 10' piece of 99% copper 10 gauge zipcord that I found on Ebay, and utilized a Blue Sea #5024 battery terminal fuse block and 40A fuse (recommended by Viair even though their portable 400P and 400P-A compressors come with a 30A fuse). I used a second 10' piece of 10 gauge zipcord and 30A fuse for my radio communications and some 12 gauge wire with 20A fuse for the connection to my Battery Tender 3 amp charger. Wiring couldn't have been simpler, and should the need ever arise I can easily isolate the compressor/communications/auxiliary battery charging systems from the rest of the electrical system.
4. The 400H comes pre-wired with a switch and water resistant cover. I decided that there is no need for a switch in the cab for an open chuck (i.e., tankless) system, and I have no issue with raising the hood at the end of a day offroading in order to turn the compressor on and off. This allows me to check the oil, coolant, etc. at the same time.. The mounting location stays dry in inclement weather and if I ever detail my engine all I need to do is put a plastic grocery bag over the compressor before spraying down the engine bay.
5. At the compressor head I could have used a simple 1/4" NPT street elbow, barbed fitting, 3/8" remnant air hose from Harbor Freight and a connector stud, but decided to address the heat buildup at the head and the possibility that hot air from the compressor could damage the leader hose. I used a "bar stock" brass tee because the additional mass of the brass acts as a heat sink to absorb heat from the compressor head, as does the Viair check valve and brass barbed fitting. I also used a 22" length of high pressure, high temperature 3/8" hose as a leader hose (expensive @ $4.95/ft., but I didn't need much).
6. A check valve isn't necessary in an open chuck (i.e., tankless) air system, but it ensures that there will never be pressure on the piston when the compressor starts. Such soft starts put less stress on the compressor and require fewer amps to get the motor turning.
7. I purchased a swivel stud rather than a standard stud which made it easier to route the air line when the system is hooked up.
8. Keep your eye open for good deals on compressors. Amazon often has the 400H on sale. I acquired a "pre-owned" compressor from a friend for $50.
Inflation/Deflation System
Set up for inflation:
Set up for deflating two tires at once (remove the green hose to deflate a single tire):
Set up for deflating a single tire:
Close Up of the Manifold
The "You'll Shoot Your Eye Out" Ralph Nader Memorial Nanny State Pressure Relief Valve and Safety Device
All of the hoses, fittings and spare parts fit in this bag:
Hope this helps someone.
The Compressor:
Electrical:
The factory 12 gauge wiring was replaced with a 12" 10 gauge leader and 2-pole connector.. Power for the compressor comes directly from the battery via a Blue Sea 5024 battery terminal fuse block and 10 gauge wire fused at 40 amps per Viair recommendations.
Factory Wiring
After rewiring with 10 gauge zipcord
Blue Sea Battery Terminal Fuse Block (P/N 5024)
Check Valve, Leader Hose and Hose Connections:
Plumbing at compressor head:
End of leader hose:
Rather than a step-by-step "How-To," here are the main points:
1. The mounting plate is a 4 3/4" x 12" piece of 11 gauge steel I found in the scrap bin of my local metal supply house ($1). I cut down an old neoprene mouse pad to cushion between the mounting plate and fender, but in hindsight it was probably unnecessary.
2. I purchased a 10 gauge 2-pole connector on Ebay. It came with 24" of wire between the connectors so I was able to cut it in half and wire one half in place of the smaller gauge wire provided by Viair from motor to switch. This allows me to simply unplug the compressor if the unit needs to be removed. [Be sure to pay attention to which way the plug is oriented. The "+" side should be protected and "-" side exposed on the battery side and the "+" side exposed and "-" side protected on the compressor side. That way there won't be a hot 12v + prong exposed when the compressor is disconnected from the battery.]
3. I wired the compressor with a 10' piece of 99% copper 10 gauge zipcord that I found on Ebay, and utilized a Blue Sea #5024 battery terminal fuse block and 40A fuse (recommended by Viair even though their portable 400P and 400P-A compressors come with a 30A fuse). I used a second 10' piece of 10 gauge zipcord and 30A fuse for my radio communications and some 12 gauge wire with 20A fuse for the connection to my Battery Tender 3 amp charger. Wiring couldn't have been simpler, and should the need ever arise I can easily isolate the compressor/communications/auxiliary battery charging systems from the rest of the electrical system.
4. The 400H comes pre-wired with a switch and water resistant cover. I decided that there is no need for a switch in the cab for an open chuck (i.e., tankless) system, and I have no issue with raising the hood at the end of a day offroading in order to turn the compressor on and off. This allows me to check the oil, coolant, etc. at the same time.. The mounting location stays dry in inclement weather and if I ever detail my engine all I need to do is put a plastic grocery bag over the compressor before spraying down the engine bay.
5. At the compressor head I could have used a simple 1/4" NPT street elbow, barbed fitting, 3/8" remnant air hose from Harbor Freight and a connector stud, but decided to address the heat buildup at the head and the possibility that hot air from the compressor could damage the leader hose. I used a "bar stock" brass tee because the additional mass of the brass acts as a heat sink to absorb heat from the compressor head, as does the Viair check valve and brass barbed fitting. I also used a 22" length of high pressure, high temperature 3/8" hose as a leader hose (expensive @ $4.95/ft., but I didn't need much).
6. A check valve isn't necessary in an open chuck (i.e., tankless) air system, but it ensures that there will never be pressure on the piston when the compressor starts. Such soft starts put less stress on the compressor and require fewer amps to get the motor turning.
7. I purchased a swivel stud rather than a standard stud which made it easier to route the air line when the system is hooked up.
8. Keep your eye open for good deals on compressors. Amazon often has the 400H on sale. I acquired a "pre-owned" compressor from a friend for $50.
Inflation/Deflation System
Set up for inflation:
Set up for deflating two tires at once (remove the green hose to deflate a single tire):
Set up for deflating a single tire:
Close Up of the Manifold
The "You'll Shoot Your Eye Out" Ralph Nader Memorial Nanny State Pressure Relief Valve and Safety Device
All of the hoses, fittings and spare parts fit in this bag:
Hope this helps someone.
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