Big Blue's Transformation

[Gary Lewis]

Bob - I'm with you.  From everything I've read the locked-rotor amperage (LRA) on an induction motor is quite high and it will take quite the inverter to power a 110v compressor.  Having said that, Janey and I are headed into T-Town to see Midway tomorrow and I plan to make at least two stops:

Harbor Freight to see if they know the LRA for their compressors.  Or, if said compressors have a name plate with the info shown in the table here at Power Tips.  If so I should be able to calculate the LRA. And, while there I'll talk to them about their inverters to see if any of them are capable of powering their compressors.

4wd Parts to talk to them about the various onboard air systems they carry as well as those they've been around.  Like maybe a York?  And how about that Smittybilt compressor?

Meanwhile, I'm reading everything I can find.  For instance, this from Jedi.com on a York Air Compressor For Onboard Air.  Note that it has links to other pages on that site about the tank, oil mods for the York, etc.

And, along the way I saw a reference to C U Off Road, and they make kits for installing a York on lots of different vehicles, but nothing is said about Fords.  So I sent them an email and we'll see what they say.  But, they have pulley/clutches and other things that may come in really handy.

So, I'm not saying no to #4, meaning a large inverter and a 110v compressor, but I doubt that's going to work.

[Gary Lewis]

Going back and looking at the discussions about tank sizes, Grumpin took these measurements:

grumpin wrote

Measurements at HFT!

62441: 30” L  10 1/2” Depth and Width

McGraw 64294 and Central Pneumatic 68740:  23 1/2" x 10"

97080: 14 1/2" x 8"

Twin tank 62763: 15 3/4" x 6 1/2"

Portable tank 65595: 22" x 11"

HTH!

And I found that:

In fact, it looks like the max height is 8" to keep it concealed as that would put it even with the bottom of the fender.  And max width is 16", but most tanks are round so that distance may be irrelevant.  If the tank is no more than 8" in diameter the length can be up to 37" long.  But if it is 16" wide then it can only be 27" long.

So with that info tomorrow I'll measure tanks at both HF awa 4wd Parts, and maybe even Northern Tool.

[grumpin]

Nothing Special wrote

I'm not saying these aren't all cool ideas.  But with this conversation starting with the idea that a $342 onboard air system might be a good option because it's cheaper and easier than a York compressor or a Smittybilt compressor that would still need the rest of the system, methinks this is sort of going the expensive / complicated route now.

If you want to be able to run an electric grill, or a table saw in your camp site, sure, go for it.  Personally I'd go back to options 1 or 2.

That was mostly tongue in cheek!

[Gary Lewis]

I think I just ruled Harbor Freight portable air tanks out.  Here's what the owner's manual says:

Regularly drain water condensation from of Tank, which can lead to internal corrosion and damage to the tank. To drain, hold Tank upside down and remove the Bypass Valve Spring (2).

Apparently there's no drain on the bottom of the tank.  

But they do show drains on the bottom of the tanks on the compressors.

[ArdWrknTrk]

Bill, Gary refers to it as a serpentine belt, I'm just following along.

Gary, I'm pretty sure this inverter is rated at 3k continuous, not surge, but ill have to check.
It came out of a fire patrol rescue vehicle.

Isn't this why AC motors come with a capacitor?
I mean, there's still some inrush, but it's nothing insane like multiple times rated amperage.

I understand you meant a throttle up mode of the ECU, but I was talking about an actual PTO driven compressor.
Or, you could get a PTO driven hydraulic pump and use that for winching -or- the compressor!

We went through all those HF tanks before.
You rejected the California Air dual hotdog tanks in aluminum as not long enough.
But at full rated SCFM @ 90 psi, I don't see the issue.

[Gary Lewis]

Grumpin - I kinda thought it was a joke.

Jim - I don't remember the details about the tank discussions. But with what I'm finding, below, I'm leaning at this point in time to a turnkey system.

All - I put together the following spreadsheet to try to get my head around the multitude of Viair offerings as well as other options. But so far all I've gotten on it is the Viair. However, it looks to me like topping up four 33" tires from 15 to 30 PSI might take all of 15 minutes at worst case. And while I know that a York would do it a lot faster, I'm questioning the need to do it a lot faster given the time it'll take up front to create the York-based system. Is it worth it?

Note that all of the numbers on there are from Viair's website, although I did interpolate from 35" tire times to get to 33" tire times since the bottom two systems don't list 33" times. And the three different pressure points I chose (0, 30, & 90) were to allow comparison to the York compressor as I so far have only found one rating on it.

Thoughts?

[Gary Lewis]

Apparently I thought about this quite a bit last night as I have come to a conclusion: The AC compressor idea isn't to my liking as the current required at 12v would be in excess of 120 amps, and that's some serious wiring.

With that I just spent time in 4 Wheel Parts and guy that helped me does do some 'wheeling.  Basically, in his opinion until you get up to the dual-compressor packages from ARB they are all somewhat limited.  His Viair gets HOT, and he's sure it'll give up the ghost due to the heat.  So he's seriously considering the ARB, but it is over $500.  

Having said that, he thinks the York compressor is the way to go, especially if you have one.  And toward that end I did get a response back from C U Off Road and they don't have a York bracket for a Ford.  But, they do have all the individual parts I'd need to make a York work.

So, given that what Bob said fits well with what this guy said, I think I'll give the York a test fit once the engine goes into the truck.  If it will fit nicely then I may go down that road.  If not, it'll be back to a 12v compressor.

[Nothing Special]

Gary Lewis wrote

....  However, it looks to me like topping up four 33" tires from 15 to 30 PSI might take all of 15 minutes at worst case.  And while I know that a York would do it a lot faster, I'm questioning the need to do it a lot faster given the time it'll take up front to create the York-based system.  Is it worth it?....

On my trip to Moab last summer I noted the time it took to air up my 33x10.50-15 tires from 15 - 30 psi.  Unfortunately I don't remember where I wrote it down.  I kind of think it might have been in one of the threads here.  But barring finding a much more reliable memory than mine, I'm thinking it was around 15 minutes.  That's with my 1.48 cfm @ 0 psi compressor, but starting with a 2.5 gallon tank at 100 psi (the pressurized tank lets me get the first tire done in a minute or so, with the rest of the time divided between the other three).

Is it worth setting up a more complicated system to go faster than 15 minutes?  It hasn't been for me yet.  But I do think about it on every trip.  As I described it a few posts back, "it takes a slightly obnoxiously long time" to get the tires reinflated.  It's slightly objectionable but not horrible for me as I do the work, but I'm a little (maybe overly?) sensitive to what my passengers think about just sitting in one place for 15 minutes.  Lesley is pretty patient, so she hasn't complained.  But if I didn't need the compressor to run when I'm towing the Bronco, and if I was doing it over, I'd want something faster.  Given those two givens, I live with it, and I'm sure you can too.

But that 15 minutes of constant running is why I felt that a 100% duty cycle compressor was necessary.  I don't know for sure that it's not OK to run a 33% compressor for 15 minutes and then shut it off for 30.  But 15 minutes seems like a pretty long time to let it heat-soak.  If you actually let it cool down for 10 minutes every 5 (if 5 isn't too long), now you're up to 35 minutes to inflate all 4 (assuming the last cool-down is while you're driving again).  I know there's no way I'd do that, so I'd end up running the compressor hot and hoping I didn't melt it.  Not wanting to be put in that situation I made sure i had a 100% duty compressor.

edit: Gary, I posted the above before your post today.  What you said there sounds reasonable.  But keep in mind the duty cycle if you go electric.

Oh, and I see that the Viair 450C is pretty close in stats to what I have, for what that's worth.

I also see you are looking at 145 psi in the tank.  I have my compressor shutting off at 100 psi.  Upping the shut-off pressure would let me get more inflation done before the tank wasn't helping, but seems like it would also be harder on the compressor in the long run.  Plus I think I'd need to regulate the pressure to my air-operated OX locker then.  I'm not saying you shouldn't run 145 psi.  It might even be quite a bit better overall.  But I think I'll stick with 100.

[Gary Lewis]

I think we think alike. I’m worried about what Janey will think as I’m airing up, so want it to be quick. And given that I might go with 35’s later, I don’t want to go too small now.

So I’m going to explore the York approach and let you know. Thanks!

[ArdWrknTrk]

And this is why I suggested a 14A 120V compressor....
My California Air has sub 8" diameter tanks, will run continuously, and has not yet tripped a breaker in a customer's house.

Wiring would be 14 Ga.
The inverter itself would be handy for other things.
And it sure as heck wouldn't take 20 minutes to air four tires from 15-32 psi.

But hey, make it as complicated as you like!  

[grumpin]

Thought I’d throw this in. I’ve seen them on electrical contractor trucks.

 They are spendy and fairly heavy, and I’m sure better, smaller ones are out there.

I would think fairly quick on pumping up tires.

https://www.harborfreight.com/9-gallon-212cc-135-psi-wheelbarrow-air-compressor-epa-iii-69783.html

Edit: won’t meet any size requirements I think you have!

[ArdWrknTrk]

11 cfm @ 40psi (about what you would want to fill the tires to) is pretty crazy!
I'm sure that's probably the volume of all four tires together.

So, air from flat in a minute, if you could get that much through a Schrader valve.

[1986F150Six]

Hmmm... grumpin and I were thinking along the same lines.

Here is another choice:

 https://www.amazon.com/Industrial-Air-Contractor-CTA5090412-Compressor/dp/B002MKP5PQ/ref=pd_sbs_469_t_0/146-6078116-3502509?_encoding=UTF8&pd_rd_i=B002MKP5PQ&pd_rd_r=8cd7e338-2bad-4bc3-b454-c26c717f521a&pd_rd_w=zQhXq&pd_rd_wg=ZX5eC&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=9G98F42GXM1JZ77DBX3G&psc=1&refRID=9G98F42GXM1JZ77DBX3G

[Gary Lewis]

ArdWrknTrk wrote

And this is why I suggested a 14A 120V compressor....
My California Air has sub 8" diameter tanks, will run continuously, and has not yet tripped a breaker in a customer's house.

Wiring would be 14 Ga.
The inverter itself would be handy for other things.
And it sure as heck wouldn't take 20 minutes to air four tires from 15-32 psi.

But hey, make it as complicated as you like!  

Jim - I'm not worried about the 120 volt wiring.  I'm worried about the 12 volt wiring from the battery to the inverter.  We are talking about 120 amps of DC current: (14 amps x 120 volts)/14 volts = 120 amps.  

This calculator says that a 10' cable to the inverter would have to be made of 4/0 wire.  Plus, the engine would have to be spinning pretty rapidly in order to generate that 120 amps.  So I do not think a 120 volt compressor is a viable alternative.

Grumpin/David - Thanks, but I don't want something that large.  Or that heavy.  The York compressor would mount on the engine and a tank would go under the passenger's side fender of the bed.  Or, a 12v compressor might go to the right of the tool box in the bed and the tank again under the bed.  But an engine-driven compressor would take up a lot of extra space as well as add weight.

[ArdWrknTrk]

Put the inverter up front....


Just like the alternator only makes what's called for, an inverter only takes what the load calls for.

My compressor runs fine on a 15A 120 circuit. While that may be 150A @ 12V, that's no bigger a cable than your 3G is using.

7" diameter twin tanks also fit within your 8x16x26 envelope.

[85lebaront2]

Very true Jim, and my 3G is an uprated 160 amp unit, and I believe if he uses the PTO function he will be spinning it fast enough to handle the running load, if he uses a nice heavy jumper cable setup like wreckers have for jumping cars, it would more than handle what is needed (Damn engineers, overthinking everything).

My lab manager was like that, his initials are CES, a couple of us referred to him as "Complicate Everything Snyder", it was bad enough that more than once he would blow through drop useless suggestions and blow out. We would go do what we planned, he would come back later and believe we did what he suggested even though it wasn't.

I had a 90 amp side terminal alternator on my 1977 F150 with the 390. A good friend had come by with his 454 Chevy crew cab DRW truck (towed his rail with it), it wouldn't start when he got ready to leave, I hooked my big (Diesel) jumper cables to his from mine, he said give it a couple of mins to charge, I could see and hear the load on the alternator. He said I'll try it, between the nice hefty battery in mine and the alternator it spun like a damn small block, he was incredulous over the speed it cranked at.

[ArdWrknTrk]

I have some heavy cables too.

Never fail to get a car started, but people sometimes gasp if they see their corroded terminals smoking when the parrot jaws sink into the lead.  

[Gary Lewis]

I looked at name plates on several Northern Tool compressors today but didn't find any that gave the locked rotor rating.  But, as I said previously, one site I found said that usually runs at 4 to 8 times the running current.  So let's take "6" as the mid-point on that range.

Your compressor pulls 14 amps while running, and at 120 volts that means it uses 1680 watts when running.  So if we multiply 1680 watts times 6 we get 10,080 watts for starting.  Let's round that to 10K watts.  And usually an inverter will have a surge rating of twice its continuous rating, so let's look for a 5000 watt inverter.

Sure enough, this one on Amazon is rated at 5K watts continuous and 10K surge.  And it costs $370.

But it measures 18.7 x 10.4 x 4.6 inches and I'm not sure I'll have that much space under the hood.  Certainly not on the driver's side as there may not even be room for the aux battery there since the coolant recovery reservoir, air filter box, PDC, and cruise module will probably fill that side.  Which means the aux battery may have to move to the passenger's side, and that will probably more than fill up that fender.

Now let's turn to the compressor.  You said California Air, and I found several twin stack ones.  But this 4620AC says it pulls 14 amps, so is it the one?  If so, it sells for $323, which brings the total to essentially $700.  But the inverter says it can't be left connected to the battery so we'll need a 200 amp relay, but they are only $20 or so.

So, let's compare this to the ARB CKMTA12, which is the top of their line and costs $542.  The ARB has 4.6 CFM at 29 PSI and the California Air has 6.4 at 40 PSI, which is the closest I could get in pressure for CFM ratings.  Obviously 6.4 is better than 4.6, but 4.6 is also twice what I was seeing in the Viair product line.  How much is enough?

So, why wouldn't I just go with the ARB?  It is designed for the offroading environment.  It is simple to install as it is a complete unit, and it costs less than the inverter/compressor arrangement.  Plus, it is known to work.  And we don't know that a 5k watt inverter will even start that 120 volt compressor.

[ArdWrknTrk]

I use my 2,000 watt Horrid Fate **Jupiter** inverter to run my California Air compressor all the time.
I am offering you a much better quality 3k inverter from a retired piece of rescue apparatus. **for free**

Isn't the start capacitor what deals with most of the inrush?
The breaker is built in to any inverter I've ever seen.
A cheap race car battery disconnect switch is all I use to tie it to the truck.

While my compressor is buried in sawdust and sheetrock dust most every day it may not be the same environment as alkaline dust from a dry lakebed or some sandy mud you might encounter off road.
Certainly I can't see how the TEFC motor is going to "lock up"

Will your ARB CKMTA 12 run the microwave to heat dinner? Or a kettle for coffee or tea?
Will it run any of the plethora of power tools my 2k W unit does?
Or auxiliary lighting, or a (tool) battery charger, or?????

You're digging your heels into a slippery slope, but then that seems to be SOP.
You're after another One Hoss Shay, and you'll get it eventually -with an inordinate amount of time, money and worry- or you could just get on with it and enjoy the ride.

**  **  edit...

[ArdWrknTrk]

My compressor is the 4610-AC. It only offers 3.1 CFM @40. (But , like I said, how much can you get through a Schrader valve?)
And draws under 9A @ 120V.

I do see that California Air is coming out with a 12V contractor model for 2020.
https://www.californiaairtools.com/ultra-quiet-series-of-air-compressor-contractor-grade/12-volt-cat-12v1010s/
But the CFM seems tiny.

Edit: the 2010A is the same pump head as mine with a smaller tank at only $169.


I KNOW for a FACT that these motors will run on my 2,000W inverter.
...also, a 1200W Samsung microwave.