I have a portable 5-gallon air tank with a 125 PSI maximum pressure (one similar to the first picture shown below) and am just wondering whether a particular air compressor with a 150 PSI maximum pressure (shown in the second picture below) should be able to fill my 5-gallon air tank to its maximum pressure without a problem.

 

If you are attaching the tank to the compressor the compressor will fill both tanks (slowly) until it reaches the pressure setting, so no problem.

My question, with a smallish compressor why not just carry it with you vs refilling a small tank?

 

The compressor (I think) has to be plugged in to electrical outlet to blow air, whereas the portable tank does not. My plan would be to use the compressor at home to fill the portable air tank and then use the portable air tank at places/situations where I have no electrical power handy to use the compressor to fill stuff with air. That would be better, if the compressor should do the job of filling my air tank without a problem, than me having to haul my air tank to the gas station to fill when I need to.

 

The compressor tank will hold pressure as long as no hoses or attachments are connected. Connect attachments just before use.

 

got it, only question is how much run time that small tank will provide!

 

I have a portable tank around that size. I don't use mine for anything other than airing up flats. It's basically good for one flat car/truck tire.

 

That compressor is not meant to handle that amount of volume. Will it do it? Yea it likely will if you have the time and it will stretch the compressor.
I have a 15 gl at home with a 3.5HP I run at 120PSI and it will run while filling a 5 gl tank and I may need to let it build once to finish within a few minutes @ 80-100PSI.
Have a 60 gl at the shop run at 120PSI and filling the same tank takes the same time as a gas station.

BTW, if it were me I would not fill that above 100psi and I usually give up around 80PSI which will do most jobs such as airing one tire as was mentioned.

How are you intending to use the tank?

 

I guess we need to know what you want to use it for. That would be okay for airing up a tire but that's about it. If you plan to use it to run air powered equipment, no. It would shoot a few brad nails before the tank ran out. I doubt it would provide enough air to take one lug nut off if you connected an impact to the tank. It could give you a 30 seconds or a minute of spray time with a small spray gun. That's about it. That compressor might say 150 psi but...

 

That compressor appears to be just under 3 cfm@90 psi capacity and would be just fine for filling an air tank.
Just fill the air tank up to the pressure indicated in red on its gauge.

 

I have a very similar situation. I find the portable air tank very useful for many small jobs, and the small compressor fills it fine. The thing I like is the air tank is small and light (which my old back appreciates). Steve

 

Although a bit pricey I'm a bit surprised aluminum air tanks are not more popular.

 

As already said, yes, that compressor will fill that tank, but I'd skip the tank and just use the compressor. The tanks are handy for someone who has a large shop compressor and wants a way to get air to something farther away than hose will reach. But with a smaller compressor like that it's a whole lot easier to use just it. I have two larger compressors in my shop, as well as a smaller portable compressor for nailers, but it's pretty heavy to just grab and go, so was about ready to break down and buy a tank so that I could check and fill my trailer tires as needed rather than backing them over to the shop. Then one day a guy who I had done a lot of work for over the years showed up and dropped off a brand new little compressor like you have pictured, and one time with that was enough to convince me to drop the idea of a separate tank. At first I wondered what I would use it for, but it's great. It's slow to pump up, and runs a trim nailer or stapler, although I've not tried it with a framing nailer, but it is perfect for pumping up and carrying across the yard to the trailers.