SPG with integrated transmitter. Am I the only one who would like that ?
- Thread starter fnog
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I could be wrong. I'm not running any numbers. But @fnog, I think you're leaving out the huge amounts of energy loss due to the many factors of inefficiency involved. If you assume only 75% loss of efficiency (which my gut says is conservative, but what does my gut know?), you're left with 2 batteries worth of power to spend.
Anyway, why bother? Get a TEG placed between the 1st stage where expanding air cools down and the diver's neck seal where it's nice and warm. If that's not enough juice, the entire suit has "hot side" and "cold side". No messing with user's air supply, no moving parts, no downside.
An interesting thought process....
Before I go further, I'll say I'm a big fan of AI. My wife and I have 8 tank transmitters between us, so we're in this big time (and for big money)
So breaking it down:
The analog gauge is still valid. Whether you have a button gauge on your 1st stage or whether like me you have spg's on all your stages as a back up. Mechanically it's simple and cheap. In reality you don't read the actual numbers, your mind reacts to the position of the needle.
Equally you're not interested in lag on your computer, again you glance to confirm your contents, and not stare at it watching the contents change.
With the current state of transmitters - I think the Suunto Eon Steel Pod is the best out there. It has good range above and below the water and once paired it stays paired until you delete it off the computer.
I'm guessing that Transmitters have reached a practical minimum size. I know Stuart above claims he doesn't need a long battery life (mine is 2 years or 300 dives) but the fact is the less you change a battery the less change of flooding (I think that's why no TX I know are really user changeable) This is all personal preference - although Stuart laments the small battery life of computers so his comment is a contradiction
At some point you need power. If your TX is going to be near passive, then the computer needs to ping it and read the pressure and thus needs a bigger battery (if we accept that transmitting required more than receiving)
The logical place possibly to put a device is in the 1st stage, but then you need a "window" to allow signals to pass through
Even a passive would need some power, you could have a small battery and possibly recharge it by using a piezo-electric device using the internal piston in the 1st stage to power it.
But now your 1st stage has got bigger and more complex.. Most computer manufacturers don't make 1st stages and vis versa.
I personally don't think AI TX can be improved much more (using the Eon as the Standard of the latest development) they can tweak them and add features but nothing radical to improve them.
I have my TX on small hoses with Quick disconnects so thay they can't be used as a handle and don't get damaged on a boat or in transit. I suspect my TX has the same amount of failure points and a normal SPG - certainly I have less O rings
Before I go further, I'll say I'm a big fan of AI. My wife and I have 8 tank transmitters between us, so we're in this big time (and for big money)
So breaking it down:
The analog gauge is still valid. Whether you have a button gauge on your 1st stage or whether like me you have spg's on all your stages as a back up. Mechanically it's simple and cheap. In reality you don't read the actual numbers, your mind reacts to the position of the needle.
Equally you're not interested in lag on your computer, again you glance to confirm your contents, and not stare at it watching the contents change.
With the current state of transmitters - I think the Suunto Eon Steel Pod is the best out there. It has good range above and below the water and once paired it stays paired until you delete it off the computer.
I'm guessing that Transmitters have reached a practical minimum size. I know Stuart above claims he doesn't need a long battery life (mine is 2 years or 300 dives) but the fact is the less you change a battery the less change of flooding (I think that's why no TX I know are really user changeable) This is all personal preference - although Stuart laments the small battery life of computers so his comment is a contradiction
At some point you need power. If your TX is going to be near passive, then the computer needs to ping it and read the pressure and thus needs a bigger battery (if we accept that transmitting required more than receiving)
The logical place possibly to put a device is in the 1st stage, but then you need a "window" to allow signals to pass through
Even a passive would need some power, you could have a small battery and possibly recharge it by using a piezo-electric device using the internal piston in the 1st stage to power it.
But now your 1st stage has got bigger and more complex.. Most computer manufacturers don't make 1st stages and vis versa.
I personally don't think AI TX can be improved much more (using the Eon as the Standard of the latest development) they can tweak them and add features but nothing radical to improve them.
I have my TX on small hoses with Quick disconnects so thay they can't be used as a handle and don't get damaged on a boat or in transit. I suspect my TX has the same amount of failure points and a normal SPG - certainly I have less O rings
Have you found the Suunto pod to have better range than the Oceanic pods? The Oceanic pods also stayed paired until you delete them from the computer. Mine was purchased as New Old Stock, so I have no idea how old the pod battery was when I got it. But, the pod is still showing a battery status of "Good" on my computer, 21 months and 100+ dives since I got it. I have a spare battery for it. As far as I know it is expected to be able to change the TX battery, but I haven't done it yet, so I'm curious what you've experienced to say that none of them are really user changeable. I did change the battery in my paired Oceanic computer a few months back with no issues.
And you are correct. I wouldn't have any problem with a transmitter whose battery showed as Low and needed to be changed after only 1 year of use.
I also lamented the small battery life of some computers, but I don't think that lamenting have to charge a computer every 2 or 3 days is much of a contradiction against wanting a pod battery to only last 1 year (if it makes the pod a lot smaller). If you're referring to the battery life meaning the reduction in capacity over time of a rechargeable, yes, I've lamented that, too, as I don't want a computer that lasts adequately on a charge when it's new, but is no longer adequate after 1 or 2 years. I also don't think that really contradicts my statement of wanting a pod to only last 1 year. And if the computer itself was not rechargeable and required a battery change once a year - or even every 30 hours, like the SW computers, that would be fine, too. I just don't want that, personally, if it comes with having the bulk that the SW computers have.
I also note a previously mentioned (apparent) contradiction: The contradiction of wanting a user changeable battery (like the SW computers have), but knocking other gear for (in the case of computers) having a USB port that has to be sealed or (in the case of transmitters) having the possibility to get damaged by water ingress from having to change the battery more often than once every two years.
I suppose a thermoelectric conversion would be less efficient (heat is one of the most degraded sources) than a mechanical source. I know nothing of alternators, but 25% efficiency sounds very pessimistic. I would expect more than 50%.
An alternator that runs in 'continuous' mode from 200 bar in to 80 bar out, to fill up a small chamber before the usual first stage piston could be tuned better, closer to the adiabatic. But if there is still a lot of heat difference, it could be supplemented with a TEG.
Even if all collected is just equivalent to 4 pieces of 18650 instead of, that is about 50W available through the dive. Not the kind of power of a lego motor, which must be under 1 watt. Which may very well be enough for the current gen Xmiters anyhow.
There was mention earlier of an electrochemical scrubbing process. I don't know anything about that, but imagining that some micro-nano materials engineering creates just the right catalytic for it, what kind of power does that require (flux of CO2, energy per gram of scrubbed CO2,... ) ?
An alternator that runs in 'continuous' mode from 200 bar in to 80 bar out, to fill up a small chamber before the usual first stage piston could be tuned better, closer to the adiabatic. But if there is still a lot of heat difference, it could be supplemented with a TEG.
Even if all collected is just equivalent to 4 pieces of 18650 instead of, that is about 50W available through the dive. Not the kind of power of a lego motor, which must be under 1 watt. Which may very well be enough for the current gen Xmiters anyhow.
There was mention earlier of an electrochemical scrubbing process. I don't know anything about that, but imagining that some micro-nano materials engineering creates just the right catalytic for it, what kind of power does that require (flux of CO2, energy per gram of scrubbed CO2,... ) ?
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