Main tank to pony connection?

[markfm]

It's pony size dependent, what impact it would have. For example, my 19CF is 1/4 of an AL80 (since they are actually about 77 CF). If I connect an empty 19CF pony to a 3000 psi AL80, they would both end up at 2400 PSI. (Since I would be spreading a given amount of air across 5/4 of the volume, the pressure would change to 4/5 of the starting condition).

A whole lot easier to just top it off at a shop, as Terry mentioned. None of the places I go charge for that -- I top them off, including up to a full fill, at the same time as I fill my regular tanks -- it's just a courtesy.

 

[NorthWoodsDiver]

There are times when I have transfilled my pony off several large tanks like using a cascade system. This only takes a small amount of air from each main cylinder but it is a pain in the *****. Get a booster or build your own (did I just say that) and than you can pump small tanks for stageing or deco also.

 

[David P]

I doubt the OP would want to spend the money on a transfer whip when she doesn't want to pay for a fill. I doubt she would want to buy a booster for several reasons, one they are expensive, two you need a tank of air to drive the booster, three she might have to put an spg on her pony to see if she gave herself a good fill, which she said in a previous post she doesn't want the extra equipment.

 

[Jorbar1551]

Generally dive shops will give free refills to pony bottles that are less than 30 cubic feet

 

[Web Monkey]

Terry,

I don't routinely use the air in my pony. If you read my original post again, you will see that I never mentioned emptying it frequently.

But when it needs a fill, it would be nice to be able to transfer some air.

There's no practical way to do it from a standard 3000 PSI AL tank.

If you had an empty 19 Cu Ft pony and a full AL 80 and a trans-fill hose, you would end up with around 2280 PSI in each. Getting anything more than that would require a compressor or a higher pressure tank to fill from.

Terry

 

[Hemlon]

Generally dive shops will give free refills to pony bottles that are less than 30 cubic feet

Thanks...I'll ask my LDS about it at my next air fill!

 

[1_T_Submariner]

I filled my buddies "Spare Air" with one of my 80s I didn't notice how much it took but, that thing is pretty small (no Flames please I don't own a Spare air). He had a fitting ad gauge to connect to a yoke valve. It worked ok.

 

[bolantej]

if you have a Sport Chalet nearby, try them. they do pony tanks for free in my area.