ARB Twin Compressor wiring to two different batteries?

[pete82]

Hi All,

I'm installing the ARB twin compressor under the trim on the LHS of my 150 using ARB bracket kit (part no 3521080). I've already got a 120Ah (100a Max draw) LiFePo battery behind my fridge in the rear and really tempted to use that rather than the starter battery as ARB suggest given the short cable run. I'd only run the compressor with the engine running so it will have 25Amp going in from the DC2DC charger while the max 80Amp is draw is occuring.

Given the wiring harness already splits the cabling into two, and they apear to be going into two seperate relays to the two compressors does anyone have a view on whether it would be a stupid idea to run one pair to the starter battery and one to the aux battery? I've already got an extra 8AWG running to the rear so that should easily manage the 40Amp load of one of the two compressors. Then only having a 40Amp draw on the aux shouldn't trouble it at all. Or do you think the variability of the two supply voltages could be problematic?

Cheers,
Pete

 

[KJ6IRM]

If you are always running the engine while using the compressor, then just wire it up to your main starter battery. There’s no advantage of running to your house battery.

EDIT: Are you mounting this under the hood? You say under the trim, but what trim? I assumed the plastic trim covers in the engine bay.

 

[pete82]

If you are always running the engine while using the compressor, then just wire it up to your main starter battery. There’s no advantage of running to your house battery.

EDIT: Are you mounting this under the hood? You say under the trim, but what trim? I assumed the plastic trim covers in the engine bay.

I am mounting it in the rear of the vehicle, behind the trim where a subwoofer would be placed in the Kakadu version. Disadvantage of wiring it to the starter battery is the additional cabling of a higher gauge that what I currently have and also the voltage drop over that run. With a battery right where I am installing it it seems a bit crazy to not take advantage of it.

 

[Washingtontaco]

I put my compressor in a similar area. I ran the twin to the house battery. Actually I have the house battery feeding a bus bar that I ran through a breaker to the compressor.

 

[KJ6IRM]

I am mounting it in the rear of the vehicle, behind the trim where a subwoofer would be placed in the Kakadu version. Disadvantage of wiring it to the starter battery is the additional cabling of a higher gauge that what I currently have and also the voltage drop over that run. With a battery right where I am installing it it seems a bit crazy to not take advantage of it.

View attachment 2884688

Yeah, just run to your house battery (the closest one). That’s what I would do if I had your setup.

 

[pete82]

I put my compressor in a similar area. I ran the twin to the house battery. Actually I have the house battery feeding a bus bar that I ran through a breaker to the compressor.

View attachment 2884746View attachment 2884748

Very neat and tidy, and like the bus bar idea, do you have a photo of that?

 

[pete82]

Yeah, just run to your house battery (the closest one). That’s what I would do if I had your setup.

Cheers, I'll go ahead with that

 

[hoser]

House battery, for sure. And run your engine while filling tires for the higher voltage and thus better compressor performance.

 

[Washingtontaco]

Very neat and tidy, and like the bus bar idea, do you have a photo of that?

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[r2m]

House battery, for sure. And run your engine while filling tires for the higher voltage and thus better compressor performance.

ALWAYS run your engine if you're using the compressor, especially those twins. I have one and it will drain my house battery in no time!

I put my compressor in a similar area. I ran the twin to the house battery. Actually I have the house battery feeding a bus bar that I ran through a breaker to the compressor.

View attachment 2884746View attachment 2884748

How's the interior noise level when running that compressor? I purposefully have mine under the hood so when I'm using it I'm not driving my wife nuts with it running.

 

[pete82]

ALWAYS run your engine if you're using the compressor, especially those twins. I have one and it will drain my house battery in no time.

I'm going to connect the ignition wire so it can't be operated without the engine running

 

[URJ150L]

Anybody know why ARB says to wire only to the starter battery? I connected mine that way but I was just following their instructions.

 

[Washingtontaco]

ALWAYS run your engine if you're using the compressor, especially those twins. I have one and it will drain my house battery in no time!

How's the interior noise level when running that compressor? I purposefully have mine under the hood so when I'm using it I'm not driving my wife nuts with it running.

Interior noise level is not bad the GF doesn’t complain. When out camping there is so much gear in the back that it really absorbs the noise.

 

[hoser]

Anybody know why ARB says to wire only to the starter battery? I connected mine that way but I was just following their instructions.

My guess is the instructions are written for the masses. You can install it anyway you want, granted you know what you are doing. There are a lot of different ways to wire up an aux battery and some ways won't work best with the compressor. If wired into the starter battery, you can't go wrong. Tech support doesn't want to deal with anybody's "custom" wiring either.

 

[jiggletits]

The GX is a nice quiet vehicle. Put it under the hood and keep it that way

 

[Washingtontaco]

The GX is a nice quiet vehicle. Put it under the hood and keep it that way

Meh, it's not like your driving around with the compressor running. Even with lockers the tank stays pressurized enough to engage to lockers.

 

[jiggletits]

Meh, it's not like your driving around with the compressor running. Even with lockers the tank stays pressurized enough to engage to lockers.

I wouldn't want to hear it for even 2 seconds, personally.

 

[r2m]

Anybody know why ARB says to wire only to the starter battery? I connected mine that way but I was just following their instructions.

As I mentioned above, running that huge compressor will drain your battery in no time at all!
You should always have your motor running when using.
Yes, that still doesn't stop one from using the compressor in ACC mode with the motor off. But it does help in keeping the person who turned on the compressor to fill their tank or lockers, forgot to turn it off and goes to bed at night with the compressor cycling all night long, thus a dead battery in the morning.

 

[pete82]

Job done, pretty happy with the result.

 

[URJ150L]

As I mentioned above, running that huge compressor will drain your battery in no time at all!
You should always have your motor running when using.
Yes, that still doesn't stop one from using the compressor in ACC mode with the motor off. But it does help in keeping the person who turned on the compressor to fill their tank or lockers, forgot to turn it off and goes to bed at night with the compressor cycling all night long, thus a dead battery in the morning.

I don’t doubt that it’ll drain your battery in no time, and I’ve never run it with the engine off for that reason, but it all comes down to how you wire the switch rather than which battery you wire the compressor too. Instructions are to run the switch to a wire that is hot only when in ING mode, thus requiring that you at least have the key in the ignition, but after that, what difference does it make which battery the compressor is wired too?