ARB Twin Air Compressor - Custom Install Question (1 Viewer)

[pdxlc200]

Hi guys, the ARB twin air compressor is actually made up of two of the single ARB air compressors in tandem. When you look at the wiring harness for the twin compressor, it has two separate positive cables, each with a 40 amp fuse. I want to delete these fuses, combine the two red wires, and run it to a single Blue Sea Systems Circuit Breaker.

The max amp for the twin system is 50 amps, and the max amp draw for the single system is 25 amps.

That being the case, can I delete the individual 40 amp fuses, combine the two red cables, and then run it safely to a single Blue Sea Systems 50 AMP circuit breaker?

 

[pdxlc200]

As you can see I already did the install and everything works, just worried that I might blow something up under load, after airing up my tires on the trail. Thoughts?

 

[TeCKis300]

It'll work fine the way you did it. No problemo.

Technically, the 40amp fuse per pump is more appropriately sized from a worse case combined initial induction surge POV, and from a protection POV, but it's likely just fine.

There's also a case for keeping the dual wiring/dual fuse, is if a single pump shorts or fails and trips only its own downstream breaker, you'll have fail over redundancy of the other pump still working.

 

[cboyd]

Well I think you have to look at the load of each compressor at max pressure and temperatures to be sure. Technically you should have used the 40+40 = 80, but given the length of cable and such, the. Best thing not knowing the max load of both compressors together is to fuse it for protection of the wiring.

The appropriate thing to do is use the cable length and gauge and compare it to the appropriate fuse value - handy chart on BlueSea’s website.

I’m guessing ARB did that and 40 is the right value high enough to avoid nuisance tripping. So the real value is probably less than 40 for each. (Likely closer to 30a)

long story short, you probably would be okay at 50 combined, but you might see some tripping here and there

 

[grinchy]

I’d go with 60. Depends as said above on your wire run length and gauge too.

 

[pdxlc200]

Ok thanks guys, that makes sense. I was curious why they supplied 40 amp, when the max output is supposedly 25 amp per compressor. I shortened the cable length by about 70% and then put 5/16 terminal stud on each, and then connected both of them to the Blue Sea breaker. Seems like the worse case scenario is that the breaker trips occasionally and I just reset it. Thanks for the insight!

 

[pdxlc200]

Well I think you have to look at the load of each compressor at max pressure and temperatures to be sure. Technically you should have used the 40+40 = 80, but given the length of cable and such, the. Best thing not knowing the max load of both compressors together is to fuse it for protection of the wiring.

The appropriate thing to do is use the cable length and gauge and compare it to the appropriate fuse value - handy chart on BlueSea’s website.

I’m guessing ARB did that and 40 is the right value high enough to avoid nuisance tripping. So the real value is probably less than 40 for each. (Likely closer to 30a)

long story short, you probably would be okay at 50 combined, but you might see some tripping here and there

"Best thing not knowing the max load of both compressors together is to fuse it for protection of the wiring." The documentation says the max load of both compressors together is 50 amps, which was why I was confused why they each came with 2x 40 amp fuses.

 

[cboyd]

Generally you over spec the fuses to degree to avoid nuisance tripping for momentary surging. But that has to be balanced by protecting the wiring. For example you wouldn’t want to upgrade the fuse to avoid the tripping and risk over-current in the wire. Thus, consulting the table for gauge and wire length.

for example the Redarc BCDC 25A specs 40A for installation for this reason. And certain gauges for run lengths... just finished that install in my trailer, so it’s fresh in my mind.

 

[KLF]

In parallel pumping systems, they will sometimes use a sequencer that delays pump #2 starting by about 2-3 seconds, so the surge is mitigated and not happening at the same exact time. Then the sequencer alternates which pump is the lead one each cycle, so they get even duty. Wonder if something like that could be used.

 

[cboyd]

The simpler the better. easier to troubleshoot and maintain.

Especially when you’re in the boonies trying reseat the bead on a tire or pump up your second flat in the spare with 4 tire plugs jammed in.

KISS is the rule.

 

[Julian73]

I found an ARB air pressure-air flow-average capacity chart for the unit, It shows at 150 psi each pump draws about 34 amps (68 total) The chart does not show motor start up amperage (stall) which is typically the highest current draw.