"Power tank" compressed gas options CO² vs N² vs O² (1 Viewer)

[toyotaboy80]

Looking into this option as my onboard air system for filling tires.

CO² might prove difficult to get but I havent exhausted my options yet. But reading into it, is there any particular reason CO² is traditionally used? I would imagine it is cheaper than N², although it kind of seems like a poor choice of gas for say if I wanted to air down to 8psi then air up to my normal 25-27psi and forget about it for 2 months until my next air down. From what I understand CO² isnt that stable and I'll be chasing the pressure around.

Is filling the tank with Nitrogren plausible? Not sure of its price or availability, but could it go in the same tank and have the same volume and PSI as CO²? I reckon this would be fairly stable set it and forget it for an air up.

Would compressed O² essentially be the same as using a standard air compressor? The only difference being it is stored at 2k psi? Also can it go in the same tank etc? I'd imagine this option isnt the cheapest, but as far as I know it is the most readily available to me.

 

[gnob]

nitrogen is pretty common at like costco etc.
imo kind of a gimmick since you can't really escape all the "air" to fully replace with nitrogen.
oxygen is flammable so no.
co2 is small and simply leaks.
pretty sure co2 is chosen because it is stable.
in reality is it that big of deal to check your tires occasionally
my co2 tires drop a few pounds after like a month.
imo its a non issue.

 

[toyotaboy80]

Realize that about O² now....pure O² and regular breathing air arent even close to the same, I should know that... lol!

Cliff notes on reading a bit about everything, CO² N² and O² all have their own bottle/specific valve. Read a bit further into regular compressed air at scuba tank pressures of 2k+ and that also has its own bottle and valve. I guess it makes sense as to not just slap random into whatever bottle you want.

CO² is stored at a much lower PSI and goes liquid under pressure. Also get around 2x the amount of CO² volume vs N² or 2k PSI compressed air in the same size tank. N² and compressed air remains a gas.

The volume difference doesnt bother me. Nitrogen is double the price of CO². Scuba tank air is cheaper than CO² but the bottle requires a yearly visual inspection to stay legal.

Nitrogen allegedly takes 45 minutes to fill the bottle...and its price. I'm out on that for sure.

Realistically not a big deal to check the pressures regularly... its just not something I do if it doesnt leak.

Gonna sleep on this for a bit I guess, and call around to see if CO² is going to be easy to get.

 

[gnob]

regular compressed air "leaks" too. typically 1 psi per degree. and a couple a month sitting.

co2 requires bottle inspection every 5 years here.

 

[1911]

The compressibility and vapor point of CO2 are it's biggest advantages. The pressure of the gaseous CO2 at the very top of the tank (as the tank is used/emptied) remains the same, as long as there is any liquid CO2 in the tank. So you get the same fill rate for airing-up tires at the end of the tank as you do when it's full.

I only use mine on the trail; rarely at home (filling flats on my ranch).

Like @gnob , I have to get mine inspected every 5 years also.

 

[toyotaboy80]

5yr hydro test on CO² and scuba tanks. Just scuba tanks also require a yearly internal visual inspection. So thats kind of a wash I guess CO² vs air fill price.

Found a fire and safety shop that will fill CO²... $55 Cad for 20lb fill. Going to give it a try if the bottle I have passess a hydro test.

According to powertank literature you can get 36 15psi air ups on a 20lber with 35 12.5 15's.... not as cheap as I'd like but would still be money ahead at the 5yr mark vs paying for any half way decent air compressor... assuming I air down 12 times in a year...which isnt likely. Cost aside I just want the speed and not having to listen to an air compressor would be nice too.

Ideally I'd like to store the bottle laying down... I understand that the bottle cant be used laying down, but is it ready for immediate use once I stand it upright or does it have to "settle out"?

 

[aztoyman]

I bought my bottle online cheaper than from the local welding supply. As recommended by the welding shop. Buying from them was expensive.

I exchange it when empty and they are responsible for the hydro testing after that. I can keep my new bottle and have them fill it but, it takes longer and costs more. I don't know why, it's just cheaper for me to swap my empty for a full one at the place I get my gasses.

I recently bought a small bottle online to make a nitrogen charging kit for my coilovers. I brought in the brand new bottle, they checked the date, put it in the empty return area and told me to take whatever full one I liked. (same capacity)

I go through welding gases well within the hydro test requirement time period so I never have to pay for it. I swap too often.

CO2 is cheapest of anything I get. You get more volume for tire fills in a smaller bottle than you would using a compressed gas. Seems to be your best option or Power Tank would probably be selling a different system.

I think I can get CO2 from other places that sell beverage and brewery type supplies. Not sure what you have available where you live. I just go to whatever welding supply has the best price at the time I need it.

Good luck with whatever you decide.

To add, different tanks and fittings/threads on them according to the material inside. Some high pressure gasses can be in the same type bottle. Co2 has different valve and connection for the regulator. Acetylene tanks are the ones you don't want to lay down. Completely different tanks,

 

[gnob]

5yr hydro test on CO² and scuba tanks. Just scuba tanks also require a yearly internal visual inspection. So thats kind of a wash I guess CO² vs air fill price.

Found a fire and safety shop that will fill CO²... $55 Cad for 20lb fill. Going to give it a try if the bottle I have passess a hydro test.

According to powertank literature you can get 36 15psi air ups on a 20lber with 35 12.5 15's.... not as cheap as I'd like but would still be money ahead at the 5yr mark vs paying for any half way decent air compressor... assuming I air down 12 times in a year...which isnt likely. Cost aside I just want the speed and not having to listen to an air compressor would be nice too.

Ideally I'd like to store the bottle laying down... I understand that the bottle cant be used laying down, but is it ready for immediate use once I stand it upright or does it have to "settle out"?

pt has a setup that allows use of tank lying down but this obviously requires you to keep a personal tank.
its not really a biggie. the tank can ride however as long as you right before use. i personally love the speed of the tank vs anything else.

 

[1911]

5yr hydro test on CO² and scuba tanks. Just scuba tanks also require a yearly internal visual inspection. So thats kind of a wash I guess CO² vs air fill price.

Found a fire and safety shop that will fill CO²... $55 Cad for 20lb fill. Going to give it a try if the bottle I have passess a hydro test.

According to powertank literature you can get 36 15psi air ups on a 20lber with 35 12.5 15's.... not as cheap as I'd like but would still be money ahead at the 5yr mark vs paying for any half way decent air compressor... assuming I air down 12 times in a year...which isnt likely. Cost aside I just want the speed and not having to listen to an air compressor would be nice too.

Ideally I'd like to store the bottle laying down... I understand that the bottle cant be used laying down, but is it ready for immediate use once I stand it upright or does it have to "settle out"?

You don't use CO2 because it's economical; you use it because it's a lot faster and easier to air up than a portable compressor when you're back to pavement.

The liquid and gas phases don't need to settle. If you store it laying down, just set it upright before you open the regulator valve. Powertank sells an upright holder/mount for their tanks. I put mine on the B pillar of my roll cage; with the top off, I can reach all four tires with the Powertank coiled hose, without removing the tank from it's mount. Makes it even faster to air up.

 

[aztoyman]

What he said. The PT guys are aired up and gone before I even get my compressor out.

 

[toyotaboy80]

Local welding supply shop does exchange only, $75 for a 20lb'er...but then its a steel tank. Seems my best option is a personal aluminum tank and take care of testing on my end. $65 for a hydro isnt so bad... 1 week turn around.

In any event it'll be sweet to have trail air. Havent ever wheeled at <20lbs tire pressure. Ive got a set of beadlocks I havent properly used... those should be next level. But even a regular rim/tire at 9psi should be pretty sweet compared to 20.

 

[aztoyman]

I've been as low as 8 psi on regular steel rims. They are only 8" wide with 12.50's on them and probably why I have gotten away with it. I would be wishing I had a Power Tank if I ever lost a bead. Not sure I could seat a bead with just a compressor. I don't have an air tank.

Post up whatever you get. I need to consider OBA or a PT for my build.

 

[BurntToast]

Any worries on CO2 leak in a closed cabin? I have a story of a lady and her mom dying from having dry ice in the back of their car on a road trip, both passed out and ended up in a ditch. Older lady passed.

 

[1911]

I've been as low as 8 psi on regular steel rims.

Same here.

 

[Mdog97]

Powertank user for 15+ years now, so I thought I'd chime in. CO2 does permeate the tires, so pressures will drop over time - not so much an issue in the summer, when we'd be on and off the beach multiple times a week, but at the end of the season I'd have to remember to find a "regular" air chuck somewhere and air down & back up to replace as much of the CO2 as possible.

CO2 is in liquid state in the bottle, so as others have said you can store it horizontal, tip it up when you're ready to air up and it's immediately ready to go - no waiting. Not that I ever had an issue, but it's "like" carrying a CO2 fire extinguisher, so I can't image getting into "trouble" for carrying bottled gas without a placard or in violation of some rule or reg. Pressure is constant across the full tank payload, until all of the liquid is gone. You can feel how full the tank is, with the liquid sloshing around inside, so it's easy to know when to go get it refilled. I've never been worried about leaks, as the regulator can be turned off in addition to the master valve for the tank itself. I have the big 20lb tank, which would last for many, many cycles of down and then back up, although this was for lower volume street tires on LCs and Mercedes GLSs, not the 33 / 34 / 35 AT monsters that some people run. YMMV. I used the local fire extinguisher place - $25 / fill as I recall; leave it there and pick it up the next day, usually, although I did wait once. A bit annoying to remove the PowerTank guard and regulator each time, but I'd rather not have someone else fooling with those. I ditched the Powertank trigger fill handle with analog gauge and use an Astro Pneumatic digital gauge/handle combo on the end of their coiled hose, but will probably be ordering their new gauge/handle combo soon, as it looks pretty slick. My tank has been hydro tested twice now I think.

I had a K size nitrogen cylinder in my race trailer years ago, strapped to the trailer wall. I used that N2 for air jacks, air tools and to fill tires (on the race car, trailer and tow vehicle). The benefit of N2 over compressor air was the lack of moisture in the N2 vs. compressor air, which meant that the temperature behavior of the gas inside the tires was much more linear predictable as you heated up the tires on the track. Super convenient to have on board N2 everywhere I went, but you have to remove the protective steel cap and wrench on the regulator when you arrive, and then reverse when you're breaking down (I leave all that stuff attached on the Powertank, as it has a sturdy guard / carrying handle). The K size cylinder is super heavy and awkward to manipulate, and the N2 inside is under very high pressure, so not the kind of thing I'd want inside the cabin of a passenger vehicle...

That said, I did talk to my gas supplier, and we tried re-purposing the Powertank for N2 use, to try to mitigate the rubber permeability / pressure drop mentioned above. He had an adapter to fit N2 flow to the CO2 head on the Powertank (they're different sizes). He was able to fill the empty (and recently re-tested) Powertank with N2 up to [can't remember the pressure]. I used my same Powertank regulator, hose etc. and it worked like a charm - light, portable N2 on the go. Cost was higher per fill than CO2, and you got a lot less total volume per tank fill, but it sure was nice to have N2 instead of C02. I did this about 2-3 times, but I'm going to switch it back to CO2, as I don't want a horizontal high pressure missile riding around in the rear of my LC. May look into getting a K-size N2 cylinder for the garage instead....

 

[AggiePhil]

I use a PowerTank for everything including wife’s tires, blowing sand off at the beach, charging up my WaterPORT, etc. Love it! Local welding supply place fills it for $27. Usually lasts me a year.