Real world tank refill #'s

[wahoowad]

Hi. I use the handy Airhog tank fill calculator (here) as I consider various air supply options. Can I expect the # of refills it suggests I will get for a given tank/pressure combo or are there losses due to such as using the bleed off valve?

For example, say I'm using a standard steel 120cf scuba tank to fill my Marauder with reservoir extension:

Tank Size: 120 cf
Tank Fill Pressure: 3500 psi
Fill Gun to What Pressure? 3000 psi
Gun Cylinder Size: 287 cc
Refill Gun When it Reaches What Pressure? 2000 psi
Number of Refills: 25

Should I actually get the 25 fills it says or does the necessary bleed off loss reduce it and they just didn't factor that into the calculation? Is there also any losses during filling? I don't know, I have not actually filled a PCP because my gun is on order. But I am weighing the cost breakpoint between some tank options.

[cactusrat]

Wahoowad you also have to considered hose length and hose diameter. You might lose a couple of fills depending on your fill set-up. Every time you bleed-off your line, you lose some air.

I use a four foot, quarter inch fill hose, so I lose a lot of air. That’s no problem for me because I have a compressor.

[Rickster]

With the extender.
You will use several of your fills filling the gun for the first time.
If you degass, you loose several  more.
The calculators don't take bleed off or the above mentioned things into account.
So you will never really have 25.