New Question: Power requirements for ARB onboard air


So, a lot has come together recently. I have a Daihatsu Rocky, and the offroad bits for it can be hard to source. I'll keep to the point for this thread here: I finally found a locker for my rig.

Even though the Rocky rear end is essentially a 7" Toyota, you can't simply throw a 7" in there: the axle shafts are all different. I didn't take it apart to see how different, only that sources in Aus say they don't work. An axle swap is much more money and hassle if I don't need to. So, after scouring the interwebz, ProTrack in Greece makes a front and rear air locker for the Rocky (known as a Feroza elsewhere). Enough reviews exist that I'm going to take the plunge.

However, ProTrack's compressor looks like a re-stickered something else, and I'd rather use something available stateside for warranty reasons. I titled this thread for ARB air, but if someone has a different idea, I'm all ears. I have one tech support reply from ARB, but not a second, and the first reply simply told me what models they sell. So, my questions:

I wanted to go with a BlueSea (or something similar) fuse block to wire this into. I would be wiring a switch for the dash to turn the compressor on.
1a. How big a fuse should I be going with for these compressors?

1b. Because someone will ask, and because it's the right question, there is a tiny air locker compressor, and then a single compressor, and then a double. Can the single do a decent job with 30" tires and a locker? (I know this is an electrical forum, but we all like bonus, extra credit questions.)

2. How much space do they need to vent air as they work? I have a nice space in the cab for any of them, and it's centrally located under the front seats, but I know they need to breathe and not get too hot.

Any help here is great, even if I simply check Question 1 off the list and then ask the rest elsewhere. I appreciate the help in advance.


Engineer In Residence
I used this kit. The tank may be a bit large, but you can source the components individually. Note that the compressor must not be mounted upside down.

This compressor took about 15 minutes inflate all 4 245/75R16 tires from 20-50 PSI. Current is about 19A, but will vary with pressure and voltage. I suggest a 30A fuse, and 10 gauge wire. The supplied wire is okay for short runs, especially if you have a good chassis ground nearby. If you have a good fuse block, run it through that. If not use the provided wiring to power the pressure switch/relay full time. The relay (gray box) can be controlled with a small gauge wire supplying ground. This can be a manual switch, auto (engine on) via a relay, or both. For example I have a SPDT switch with center off. I can set the compressor to engine on, or manual on, or Off.

The lockers use very little air, so just about any compressor will do.

The compressor should not be mounted in a closed compartment, it needs at least 5-6" of space on the sides for air circulation. Inside the cab, or under the vehicle is fine. The engine compartment works, but you need to keep your duty cycle under 15 minutes in hot weather.


Rock Stacker
You will need a relay to run just about any air comp. A 10a dash mounted switch is too small to handle the load. I have had a extremaire (4cfm) VERY happy with it, two cons are price and large size. My new build is going to use the same comp shown above made by Viair. Never had one but people rave about them, so I'm gonna try one.


Viair with relay and distribution block:



Thank you for these replies, guys. I stayed away from this post (and one more about batteries) because I've been trying to sort out what the electrical will be like. Once I do that, I will know what I have for space.

I believe we are going to try to cram dual Type 65s in there; there is just enough space with the size of the battery to sit on top of the fenders on both sides (not enough room on either side to fit two with one) and since I've deleted the A/C, there is space in there for some sort of fuse block for extra fun: I have a new dash to put in, but I have to take things one at a time to see what space I have. For instance, I believe I'll swap to rear discs at some point in the next twelve months, mainly for a stronger e-brake and parts availability...but now I'll need a larger booster, so I have to leave room.

I believe I have plenty of space under my seats to do "stuff." The seat mounts were built this way to avoid cutting/plating my floors where the old seat mount bars were (you can see the holes on top where I can fit a deep well socket through to bolt in) but if I went and plated the floor, there is enough width there to mount a compressor under either seat. How much airflow it got would be the question, so I'd have to do something for that, too.



Man On a Mission
Mate if you don't want to blow up Tyres Then get the little ARB CKSA 12, because it is the Actual compressor for running lockers and it is very cheap but it is the proper compressor made solely for Locker Actuation, If you want to blow up tyres as well then you want the ARB CKMA 12 because this one will work both Lockers and give you a good Air Supply for those size Tyres, you truly don't need any thing else or bigger, I have the portable version of the CKMA 12 and the Portable Twin but you just don't need the Twin because it is bloody heavy and the cost of the thing is not bad but you just don't need it, I have both the single and the Twin and 99.99% of the time I grab the portable single because it is much nicer to use and it is light, If you must have on board Air then get one of the first two I mentioned, Ok.

Hope that helps.