LP vs HP?

[xiSkiGuy]

Stu, unless I am mistaken (entirely possible) I believe 85's are full at 2400, the 2640 is for the + 10%, no? (http://www.techdivinglimited.com/pub/tanks.html)

LP tanks have to be filled to 2640psi (2400 + 10%) to be at rated capacity or "full". The term "overfill" is a little confusing.

 

[Hoosier]

It is hard to tell because of it is totally depending on your diving environment.

I don't think an overfill practice on LP is common in So Cal, specially in the charter boat. (Please let me know if I am wrong). And, I am not sure if you need that much air (overfill) for the wreck diving.

I have three 130cfs and a 119cfs. But, if I do it agian, I will get all LP tanks because it will give less fatigue to the compressor and easy to get a right fill.

HP 100 is a great tank, but there is no point if you can't get a right fill (I mean a real right fill, not 3200, 3300, or 3400 psi).

My 2 bar!

I live in a mixed marriage: my wife LOVES her HP100's and I just got two LP108's to replace my LP125's today.
Still, we manage to stick together despite this almost insurmountable obstacle.

Are you sure that your back will be fine? I hope so....

 

[Stu S.]

I use the Tech Diving Ltd. cylinder chart as a handy reference. I looked up a faber LP-85, like I use. It says "Final capacity, in cu. Ft. (+10%)" on that table is 85. That's why I mentioned 2640, like Jimmer is saying.

The 85 is easy to dive with, particularly with a 3200 psi fill. If it wasn't for the overfill, I would not have bought it. Somdeday, I may have to settle for 2640 only , and I might just sell out then.

 

[Tom Winters]

THose LP125's doubles Tom? If so whats your workout plan

No way. I got them off a guy in Tampa who twinned them for caving. The treks into the cave areas did his back in. The ocean guys get it coming up the ladder.
I dived them pumped to 190 cubes, so each tank weighed in at 58 pounds, and that was enough for me.
I have twinned Faber LP85's - those are sweet and I only put 200 total cubes in them. The boots mark up the boat though.
The thing that keeps me alive is no matter what else I do in a day, I always do 400 crunchies at night. Otherwise, I'd be out of diving by now like too many other bad old backs.
I got the 108's because I could not carry the 125's without bending my arms to get them off the ground, and that got old over the course of a long dive day.

 

[limeyx]

It is hard to tell because of it is totally depending on your diving environment.

I don't think an overfill practice on LP is common in So Cal, specially in the charter boat. (Please let me know if I am wrong). And, I am not sure if you need that much air (overfill) for the wreck diving.

I have three 130cfs and a 119cfs. But, if I do it agian, I will get all LP tanks because it will give less fatigue to the compressor and easy to get a right fill.

HP 100 is a great tank, but there is no point if you can't get a right fill (I mean a real right fill, not 3200, 3300, or 3400 psi).

My 2 bar!

Are you sure that your back will be fine? I hope so....

The SoCal boats I have dived on will usually fill an LP to 3K hot which cools to 2600-2700

The "LP gets a better fill" is just faulty logic.
What would you prefer ? A "Full" 104 at 104 cft or a "overfilled" 104 at 130 cft or a "not overfilled" 130 at 130 cft ?

The tanks are all the same physical size. It's not about how "full" the tank is, it's how much gas you can get in a given physical dimension given your fill limitations.

EDIT: it's like saying you either have a 10 gallon gas tank "100%" full (LP) or a 20 gallon gas tank "50%" full (but where the gas tanks are the same physical size but the bigger costs more) -- which is "better"

Well, if you dont mind paying the $$ and can get enough 3500 fills, give me the HP any time and screw the "stress on the compressor" (unless it's my compressor

 

[Hoosier]

2600~2700 psi on LP tanks after being cooled is a right/real fill to me, not overfill at all.

I prefer 130 psi at 130cf if I can get an air from other source, but it isn’t common depending on the locations. And, I prefer 104 at 104cf if I have to use my own source.

No. my point (high/overfill) is more than a size issue. It is much easier to get a right/over fill on LP tank than HP tank like your example (Up to 3K pump and then 2600~2700psi). In HP tank, you might need to get almost 4K for the final right pressure, 3442 psi. It isn’t a normal practice for most LDS to pump up to 4K except a few locations. Of course, you might leave the tank and top it off later though. It is another travel cost in most case.

So, if you can get only 104 at 130cf tank, there is no point to get HP tank.

LOL~~~ If there was no travel cost and got a right fill, even with $ extra charge, I wouldn’t invest a huge $$$$ for my baby….

 

[idive2]

I've actually been getting good fills on my HP100 at World Watersports
in Key Largo, this was actually a place I only expected 3000, maybe just a couple
lucky fills. I dont have many dives on my HP100 but really do like it on those
deeper dives where that extra air is noticeable and appreciated. I wasn't aware
that the LP tanks were that much heavier, they had my curiosity up but I don't
really want much more weight. I do like the guarantee of at least a proper fill
and the likelihood of a bit more with the 2400-2640 tanks.

 

[limeyx]

[

No. my point (high/overfill) is more than a size issue. It is much easier to get a right/over fill on LP tank than HP tank like your example (Up to 3K pump and then 2600~2700psi). In HP tank, you might need to get almost 4K for the final right pressure, 3442 psi. It isn’t a normal practice for most LDS to pump up to 4K except a few locations. Of course, you might leave the tank and top it off later though. It is another travel cost in most case.

[/FONT]

Sure, if you can never get a 3400 fill, then you either need a physically bigger tank (LP) or be resigned to the LP tank you have etc.

But many people seem so concerned with getting a "full" tank when "full" means different amount of gas for different tanks.

Sometimes you see posts where someone essentially says they would prefer 2640 fill in a LP 104 compared to a 3000 fill in a 130 because the LP is more "full" and that's just nonsense.

 

[Hoosier]

Sometimes you see posts where someone essentially says they would prefer 2640 fill in a LP 104 compared to a 3000 fill in a 130 because the LP is more "full" and that's just nonsense.

Yes. I agree with you in that point. So, I said, LP tank, not HP one.

I was trying to point out the case in a practical manner. I never get a right fill on HP tanks, even with an extra $$ in my area. Even after having my own source, it led another factor, a compressor workloading... LOL~~~~

 

[Stu S.]

I wasn't aware that the LP tanks were that much heavier, they had my curiosity up but I don't really want much more weight. I do like the guarantee of at least a proper fill and the likelihood of a bit more with the 2400-2640 tanks.

A Faber LP 85 and an Aluminum 80 are almost identical in weight on land. In the water the steel tank is less buoyant, so you need less lead on your belt, typically four pounds less.