Anybody using smaller paintball tanks as onboard air?

rayra

Expedition Leader
Looking around at tank options to add to my Sub and surprised to find out that much higher pressure scuba tanks (3000psi+) cost about the same as a regular compressor-filled air tank (200psi) at around the same physical size.
More browsing around and I learned that smaller tanks used by paintballers are available at those very high pressures. So I'm wondering just how small of a tank would be enough to air up a set of tires 3-4-5x?

I have a small portable 12v electric compressor but it can scarcely fill a 31" flat tire before going into thermal shutdown. I have a 1000W inverter in my vehicle, I could run a smaller portable 110VAC compressor that I sometimes use for home remodeling work, but who wants to lug all that around. Being able to take a smaller bottle and coiled air hose out of my storage drawers would be just the thing. So I'm curious to learn more about the idea, if anyone has anecdotes or experience or links to share.
 

outback97

Adventurer
Looking around at tank options to add to my Sub and surprised to find out that much higher pressure scuba tanks (3000psi+) cost about the same as a regular compressor-filled air tank (200psi) at around the same physical size.
More browsing around and I learned that smaller tanks used by paintballers are available at those very high pressures. So I'm wondering just how small of a tank would be enough to air up a set of tires 3-4-5x?

I have a small portable 12v electric compressor but it can scarcely fill a 31" flat tire before going into thermal shutdown. I have a 1000W inverter in my vehicle, I could run a smaller portable 110VAC compressor that I sometimes use for home remodeling work, but who wants to lug all that around. Being able to take a smaller bottle and coiled air hose out of my storage drawers would be just the thing. So I'm curious to learn more about the idea, if anyone has anecdotes or experience or links to share.
I have not tried it, and I haven't checked the math at this link, but see here:

It's an interesting idea, but I'm guessing the consensus here will be, "just get a better 12V compressor".

ETA: I'm getting similar numbers in my estimates... a 32" tire is around 6000 cubic inches of air volume. You'd be able to air your set of tires back up from say 18 to 30 PSI a total of one time. Then your little ~70 cubic inch tank is spent. Not worth it IMO.
 
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luthj

Engineer In Residence
Its easy enough to calculate the volume of those tanks. PV=nRT. (ideal gas law). Since the weight of gas, temperature, and pressure are know, you can convert thus.

Tank volume x Tank pressure = Tire volume x Tire pressure HvHp=TvTp so a 1 liter 3000 psi tank will yield 100 liters at 30 psi.

This site will let you calculate tire volume. A 245/75R16 tire has a volume of about 68.7 liters. So to inflate from 15-30psi you need 34 liters at 30psi. So for the 1 liter tank in the example, you would be able to air 3 tires from 15-30psi.


There are several good 12V air compressors that will inflate 4 30-31" tires from 15-30 in 10 minutes or so. There are some discussions about this in this subforum and the gear section as well. There are a number of units in the sub 100$ category that will run for 30 minutes straight without cooldown, which is enough for 4 tires.
 
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kmacafee

Adventurer
I’d have to second the better compressor option. I bought an Extreme Outback compressor probably 5 years ago and it has performed flawlessly. It will fill tires all day and never shut down. Is it expensive? Probably but when you need a good compressor, you can count on it.

 

outback97

Adventurer
This site will let you calculate tire volume. A 245/75R16 tire has a volume of about 68.7 liters. So to inflate from 15-30psi you need 34 liters at 30psi. So for the 1 liter tank in the example, you would be able to air 3 tires from 15-30psi.

That's a nifty calculator, hadn't seen that one before. My oversimplified tire cylinder volume minus rim cylinder volume estimate was a bit high.
 
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CampStewart

Observer
Where would you store this tank? If inside the vehicle than I would think it would be fine even if the tank is long out of date. They are designed for 2k to 4k and you would be getting to maybe 150psi. If i was wanted a air tank in my Suburban I would be looking to put it under the body and would want something more abrasion friendly than fiberglass or thin aluminum. Now a Aluminum scuba tank would probably be plenty durable underneath. I am under the impression that fire extinguishers are pressurized to about 100psi. They might be another alternative.
 

rayra

Expedition Leader
Thanks for the swift answers.

Well I've got storage drawers in the back, height-sized to fit a 50cal ammo can, ~8", so I was looking at smaller tanks to just put in a drawer. The math above comes out well less than my hopes for a 3k psi small tank.

I also could do this on a trip where I know I'll be deliberately airing down, but something smaller that's always in / with the vehicle would be preferable.



Just really don't want to spend the bigger money for a 'ExPo'-flavored compressor. Got too many expensive hobbies as it is. Always looking for that 'value' sweet spot. Can't afford / won't spend 'buy once cry once' pricing on anything.

I started off looking at the 2.5gal 200psi tank thats available, fairly sure that can be mounted and reasonably protected in the undercarriage and had wanted to hard-plumb to QD connectors in both bumpers. But then realizing its capacity would go far I started looking at the higher pressure scuba tanks etc.

I've also intended to upgrade / modify a front brush guard with a 3" mandrel-bent pipe bumper protector and turn that into an air tank, but it would also only hold about 2.2gal. At a max refill of ~150psi from home or gas stations, it's not really worth the effort.
And I also sort of prefer having a portable compressor vs a hard mounted or engine driven one. Be able to move it from vehicle to vehicle.
 

Utah KJ

Explorer
It's all about the regulator. The biggest part of the cost of a Power Tank is the regulator which believers high volume and pressure.


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