PERDIX or PERDIX AI?

[RyanT]

I would suggest to watch the video in the first post in this thread before you shell out for the VPM upgrade:

I agree with stuartv, the "upgrade" is a waste of money.

 

[Texas Torpedo]

Correct, which is equivalent to the o-ring holding the plug in if the port is unused, so this continues to be a moot point..... I don't know why folks continue to use a point of failure analogy......

I'll start by saying I always have an analog gauge on either my rec or tec rigs but I wouldn't feel unsafe diving rec with just an AI transmitter, as Stuartv does. In the event of a transmitter failure, you'd simply call the dive and ascend. Or, if you are experienced, really know the dive site / profile, your RMV, and how much gas you had left at time of failure, you could continue the dive but cut it shorter than normal.

On the topic of failure points... I'll say this. I've had 2 HP hoses rupture on me, yet I've never had an actual failure of an AI transmitter. I've had them drop connection for a few seconds here or there, but never a flood or failure in over 400 dives with them along for the ride. I've also had small leaks at the SPG and HP hose connection point, but they were no big deal and just required an o-ring swap at the spindle. I have also had one analog SPG fail completely (locked up) and another SPG that was off to the tune of 260 PSI. The one reading incorrectly was of the greatest concern to me as I didn't know I had a problem until I happened to put a AI transmitter on that regulator set. After that experience, I feel that having both is an additional layer of safety.

I see the OP has already made up his mind, and he really can't go wrong with either AI or non.. Personally, I'd go with the AI if buying new, just in case you change your mind in the future. There may come a time when you want to track your breathing rates during specific types of dives and depths for future planning or purely historical purposes.

With regard to VPM.. I have done all my previous deco dives and at least 75% of my recreational dives using VPM/B+3 and have never had so much as a niggle after a dive, much less (thankfully) gotten bent. I do find the latest threads relating to VPM quite interesting, and definitely worth reading. Now that I have moved to Shearwater from Liquivision, I'll be using GF instead. Its well proven and most of my friends have been using it successfully for years without issue.

Enjoy whichever Perdix you end up with. I absolutely love mine and I'll probably pick up a second one used in the near future.

 

[Kevrumbo]

....So I do not need to consider other Shearwater models but PERDIX.
That leaves me w 2 options. I am considering pros and cons of AI model. It is nice to have gas metrics on the screen, however, it introduces one more element which can break, and - more important - an HP one. Also the electronics can break (though this situation is backed up by a good ol' SPG.) Also, monitoring my gas supply using SPG is already something quite automatic for me.

Let me know if I am overlooking some good reason why to buy AI? I do not want to start any feature nit-picking flamewar, I am just curious if there are some uses to this than what I can see.

It takes longer to describe & explain the process below than to actually do it -and to show that you really don't need the extravagance of wireless/hoseless AI. . .

For example: I have a full 200bar AL80 tank and consume 30 bar in five minutes at 18 meters depth; therefore after five minutes I know have 170bar remaining (200 - 30 = 170 bar):

So five minutes elapsed time and my SPG should read 170bar -check the SPG! It does.

Another five minutes for total ten minutes elapsed time and my SPG should read 140bar -check! It does.

Fifteen minutes elapsed time and my SPG should read 110bar -check! It does.

Twenty minutes elapsed time and my SPG should read 80bar -check! It does, and then start a multi-level ascent to the shallows around 9 meters where I use 20 bar in five minutes. Finally ascend to complete a three minute safety stop, break the surface & inflate bcd, and I know before even looking that my SPG will show 35 to 40bar remaining.

And so begs the question: do you really need the expense of wireless AI to tell you what you already know about your consumption rate (or should be motivated to learn & figure out in the first place), over the practical & economic utility of a basic bottom timer/dive computer and SPG? Is it really so hard to perform the subtraction arithmetic above -both on pre-dive planning & real-time during the dive- without an AI feature?

[Especially for all Metric System users with typical nominal pressure Sac rate values of one to two bar per minute, you don't need the Air Time Remaining functions of an AI feature: In other words, how difficult is it to do in your head multiples of 1 bar/min or even 2 bar/min??]

 

[kelemvor]

I think it's pretty well established that nobody needs AI or Hoseless AI for that matter. Just as nobody needs power steering, or automatic transmissions. Some people prefer AI or Hoseless AI, and some people prefer power steering and automatic transmissions. If you can dive without AI then you can dive with it. If you can dive without automatic transmissions then you can drive with them. It's simply a matter of personal preference, and weather or not you think the feature is worth the cash it costs.

Personally, I don't see why there's much debate outside of specific use cases such as cave or other technical diving.

 

[Kazeone]

It takes longer to describe & explain the process below than to actually do it -and to show that you really don't need the extravagance of wireless/hoseless AI. . .

For example: I have a full 200bar AL80 tank and consume 30 bar in five minutes at 18 meters depth; therefore after five minutes I know have 170bar remaining (200 - 30 = 170 bar):

So five minutes elapsed time and my SPG should read 170bar -check the SPG! It does.

Another five minutes for total ten minutes elapsed time and my SPG should read 140bar -check! It does.

Fifteen minutes elapsed time and my SPG should read 110bar -check! It does.

Twenty minutes elapsed time and my SPG should read 80bar -check! It does, and then start a multi-level ascent to the shallows around 9 meters where I use 20 bar in five minutes. Finally ascend to complete a three minute safety stop, break the surface & inflate bcd, and I know before even looking that my SPG will show 35 to 40bar remaining.

And so begs the question: do you really need the expense of wireless AI to tell you what you already know about your consumption rate (or should be motivated to learn & figure out in the first place), over the practical & economic utility of a basic bottom timer/dive computer and SPG? Is it really so hard to perform the subtraction arithmetic above -both on pre-dive planning & real-time during the dive- without an AI feature?

[Especially for all Metric System users with typical nominal pressure Sac rate values of one to two bar per minute, you don't need the Air Time Remaining functions of an AI feature: In other words, how difficult is it to do in your head multiples of 1 bar/min or even 2 bar/min??]

Awesome comment

 

[Kazeone]

Awesome comment

You killed the discussion nuff said

 

[Mike1967]

My AI transmitter is over 2 years old and the battery still registers as "Good" on my computer.

I really should know but where do you get that info?

 

[guruboy]

I really should know but where do you get that info?

It tells you if it’s low. So I guess if it’s not low, it’s good?

 

[Mike1967]

It tells you if it’s low. So I guess if it’s not low, it’s good?

I mean where on the computer is the info on transmitter battery condition?

 

[guruboy]

On the screen?

Where it tells you the pressure.

RTFM