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Wibble's CCR odyssey

Discussion in 'General Scuba Diving' started by Wibble, Jul 5, 2020.

  1. Wibble

    Wibble Fish don't talk
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    Love the idea of using 'standard' tool batteries; just buy more if you want to do two-dive days.

    The prices are really good too, a third of the price of the Piranha. Very seriously considering getting one. But not at the same time as the new rebreather!
     
  2. Wibble

    Wibble Fish don't talk
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    How much difference is there between the "Travel" and "Tech" versions? The latter's supposed to be better trim in the water; does it make a lot of difference?
     
  3. nickb

    nickb Well-Known Member

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    Travelling with a lithium-powered scooter was a nightmare before Dive-Xtras came-up with this brainwave.

    With this system, you can legally travel with your power packs or, if you're travelling to almost anywhere in the civilised world, pop into Home Depot etc. and buy a few packs.

    Plus, when your batteries have worn-out, you can look on Amazon for some fresh ones rather than going back to the DPV manufacturer for an expensive replacement.

    I'm surprised the competition haven't stolen the idea (yet) TBH.
     
  4. Dave Whitlow

    Dave Whitlow Super Moderator
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    The tail is the same on all three scooters so the performance is the same and the electronics are programmable. The three variants differ in tube length, the Exploration can use 4 battery packs.

    There's lots of stuff on the Dive Xtras youtube channel and in January Janos had a try at Vobster and did a write-up published in Scuba magazine (May 2020).

    The Travel has the shortest tube and can be made neutral with a pair of 5Ah batteries but is still tail heavy. With bigger batteries it is hard work.

    The extra buoyancy of the Tech allows for bigger batteries up to a pair of the 12Ah packs. As Nick says, the travel clip separates the batteries so they are permitted on passenger planes.
     
  5. barrygoss

    barrygoss Active Member

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  6. Wibble

    Wibble Fish don't talk
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    Am amazed this idea isn’t adopted for other high battery power uses such as electric pushbikes.
     
  7. Dave Whitlow

    Dave Whitlow Super Moderator
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    When I first saw this with the Piranha I was astonished by the obvious simplicity of the solution. For the buyer it is great. For the seller it carries risk as it removes the built-in obsolescence of an expensive battery with limited life, and the need for the customer to return with the choice of refreshing the battery, or investing in a whole new scooter. Perhaps others vendors seek to retain ownership of their customers when this inevitable decision arises.
     
  8. Wibble

    Wibble Fish don't talk
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    It’s unlikely that scooter manufacturers would want to build a business strategy out of selling replacement batteries, or even selling batteries for that matter. Getting rid of the battery massively simplifies transport from the factory, especially given the lithium ion air freight restrictions, it makes the whole scooter cheaper, etc. What’s not to like!

    Very seriously considered buying one, only the move to CCR stopped that plan.

    Need an easy life with no distractions for the first few months of CCR. Had enough of making my life overly difficult last year when diving with three stages plus camera. Still don’t have any decent photos to show for it!
     
  9. nickb

    nickb Well-Known Member

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    Very few people become good at something merely by throwing money at it.

    All the gear.....etc.
     
  10. Wibble

    Wibble Fish don't talk
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    Getting good needs experience. Experience needs time. Alas I didn't start diving 40 years ago, but have done a lot in the past 8 years. Pity that some on here measure me by my early day skills.

    The best thing is to spend the next 5+ years diving with the right kit for the diving I like; investing in decent training and time to practice the skills will be the best way to kickstart that journey.
     
    Tribal Chestnut and jps like this.
  11. Vanny

    Vanny Well-Known Member

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    Sure we all started somewhere, all still learning. Like I’ve said it’s a journey , it’d be boring if the journey stopped.

    happy to do a dive day when your up and running.
     
    Wibble likes this.
  12. Wibble

    Wibble Fish don't talk
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    Yet more pre-course kit fettling today. This time adjusting the harness, configuring a backup bailout reg, swapping out the drysuit heater connector and checking that the trusty old Tec4 umbilical torch works on the big battery mounted on the unit. Also noticed a hose was mis-routed.

    Did what I think is a pos and neg test.

    Hoping that all this time is well spent getting to know the unit. Looking forwards to learning how to maintain the unit on the course.
     
  13. Wibble

    Wibble Fish don't talk
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    Exceedingly pleased with the MOD1 course on the new Revo rebreather. Went for a dive on the Kyarra with my instructor which was just brilliant; everything I ever wanted from a rebreather. The peace and calm is quite amazing with only the noise of the flapper valves disturbing the peace. Just love hovering motionless watching the flora and fauna get on with life.

    Thanks to @Vanny (I think!) who told me not to try it before the course. I didn't and was all the better for being a full CCR virgin :)

    Had lots of drills, skills and some genuine incidents on the course. Lots of time to practice buoyancy skills. The main revelation was to stop trying to use the drysuit only and do what I normally do on open circuit; use the wing for coarse changes and drysuit for fine control. Once I accepted it's a horseshoe wing, all calmed down and seem to be in control.

    The couple of incidents were related. During the first 'dry' day, we noticed one of the flapper valves (in the mouthpiece) was not quite sealing correctly. Actually both had issues; a clean solved the first one, but the second needed a replacement flapper valve. At the end of which I didn't tighten the jubilee clips enough (was afraid of pinching the hose). This caused a leaky mouthpiece which got steadily worse over the first four dives -- great practice in clearing the mouthpiece though, shaking the excess water into the unit. Seems that it worked loose and I found I couldn't breathe anything but water through the mouthpiece. A bailout ensued an a forced end to the dive.

    Good practice and a chance to see just how well a Revo handles water ingress. Opened the back and a fair amount of water came out, but not a complete flood. The cells were definitely damp, but not immersed.

    As an aside, if you completely drowned a Revo, you'd obviously need to replace the five cells and might possibly need to re-crimp the Molex connectors. But that's all as everything else is fully potted. Would be interesting to see how other units would fare -- and would you need to send it home to mummy for a service?

    Mopped out the unit using the readily available cloth. Re-closed the unit following the checklist and all was fine. Ran a negative test and found the hose would droop within a minute. Swapped the mouthpiece and hose with another unit and tried it again: success! So something wrong with the mouthpiece... then discovered the sloppy jubilee clips. Fixed. Went diving. Wasn't my suspicion of loose lipped Wibs. Now knowing what had caused it, I'm sure any other unit would have been just as wet to breathe from.

    Next dive brought the really interesting challenge.

    Just for Barry, Revos use five cells -- oh what exorbitance, Revo divers are so wasteful having so many cells and it will obviously cost us so much more than other three-cell rebreathers. Wonder why that is when every other rebreather uses a mere three...

    During the week we note down the voltages from the cells as part of the assembly checklist. It was clear that one of the cells was being a bit slow and low. If I had a spare cell it would have been swapped out. But we didn't as nobody has any spare cells at the moment, so it was moved to position 1, AKA the naughty step.

    Cell 1 was a bit slow to respond on the pre-breathe, but seemed OK to jump in. Then noticed that cell 2 was being slow too. However cell 3 on the controller and cells 4 and 5 on the backup all showed higher PPO2 readings. So I actually had a genuine two-cell-failure. I -- as a newbie numptie -- could clearly see that cell's 1 and 2 were reading low together and the voting logic believed those two over the good cell. We were shallow and left it running like that and cell 2 eventually dried out (almost certainly some water on the cell causing it to read low). Cell 1 eventually came up, so five happy cells.

    Have now moved cell 1 to the backup position 1, e.g. position 4.

    As far as I'm concerned, this completely vindicates Revo's design of two completely separate electronic systems with three cells on the Petrel controller and two cells on the backup Nerd. BTW the recommended Revo cell replacement period is one cell every 6 months -- somewhat less than other units with three cells that are far more reliant on pre-emptive replacement as they're depending on cells not failing together.

    However, for me the most impressive feature of the Revo is the two scrubbers in conjunction with the scrubber monitoring system. In essence this is a system that accurately predicts the remaining scrubber life given the current use, gender and weight of the diver. Because it monitors both scrubbers, the moment the second scrubber starts absorbing CO2 can be accurately detected, this has been built into the model and so the accuracy can be validated. This is displayed in the Shearwater as remaining scrubber time in hours and minutes.

    The Revo is meant to run and consume one scrubber only. The exhausted first scrubber is taken out and emptied, the second scrubber moved to the first position and the expired scrubber refilled and placed in the second position. Twin scrubbers in conjunction with the Revo Monitoring System (RMS) makes the Revo very frugal with Sofnolime and exceedingly safe as it detects scrubber usage in realtime.

    For example, this meant I did two dives in a freezing quarry totalling 100 minutes on Monday, the RMS showing 3 remaining hours on that scrubber, so no change required. We then dived the Kyarra on Tuesday for 70mins, after which the RMS showed there was still a remaining 1h55 on one scrubber. Two days for 1.3kg of lime, a Billy Bonus.

    The other benefit of two scrubbers in series is it pretty much eliminates the risk of CO2 breakthrough. The RMS monitoring will alert you if the limits are reached and the second scrubber becomes active. As far as I’m aware, no other rebreather has this feature -- the TempStick doesn't come near to this level of sophistication. All others have to factor in a great deal of contingency, therefore consuming considerably more lime.

    Yes, I'm utterly chuffed with the Revo. I'm delighted at having a hard course with lots of work and some proper failures too. Actually, one other failure -- the HP hoses I reckon were crushed in storage resulting in some Champaign bubbles out of the hose near the SPGs (both sides!). The unit was second hand, but had only been dived twice in two years by the owner (condition and logs easily backed this up). After the course (day 6) I replaced the SPGs with the Air Integration (with two different coloured transmitters) which are simple to use as the Nerd backup displays the pressures in the 3rd cell position on the display.


    Have booked some more diving this weekend in the sea. Will work on finenessing skills and always taking more than adequate bailout.
     
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  14. barrygoss

    barrygoss Active Member

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    Lol.

    I’m well aware of rEvo’s I’ve dived one and taken it apart and am the reason the rEvo Dream has a piezo on the front as I have one fitted to the kiss and asked Paul for the schematics so I could fit the piezo as the tappy tappy was annoying me.

    Five cells to 30 month oldest cell makes me laugh. The probability of a good batch of 100 cells by 30 months 52 of the 100 would have failed during use. On a three cell system with no cell older than 18 months 1 cell might fail in the 18th month - that’s from rEvos own paper on understanding oxygen cells. So you’ll experience more cell failures than a 3 cell system. But hey, glad you’re enjoying the silence, we all appreciative of a bit of silence.

    B
     
    #34 barrygoss, Jul 22, 2020
    Last edited: Jul 22, 2020
  15. Wibble

    Wibble Fish don't talk
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    Just looking forwards to the next chapter in my diving career. It's an enabling tool, hopefully opening up some bucket list dives including Malin's depth, the Cenotes and a bunch of other exotic locations.

    It's interesting reading Revo's two Oxygen sensor papers: part1 and part2. Whilst it could mean more failures simply as there's more sensors, it also means more redundancy, so a cell that's beginning to fail doesn't need to be immediately replaced as there's others to compare against.

    Anyway, the only thing that matters is I'm happy with the unit as it's me that has to live with it for the next ten years before I hang up my diving boots for good.
     
  16. barrygoss

    barrygoss Active Member

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    It will mean more failures as by month 30 at least every dive will be a 50/50 chance of a cell failure (or multiple) whereas the three cell units are 1/100 at month 18. But enjoy.

    Have you read Zorg? https://www.nigelhewitt.co.uk/diving/rant/zorg.html scrubbers are all about dwell time.

    B
     
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  17. Vanny

    Vanny Well-Known Member

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    Glad you had a good course and enjoying the experience.
     
  18. Dave Whitlow

    Dave Whitlow Super Moderator
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    I don't get the RAID approach to cells. It defies logic to run them beyond their reliable life when they are so important. John Lamb, maker of cells, is quite clear about their shortfalls and limited lifespan. I suffered through the AP O2 sensor drought and lots of unreliable cells is really nor the answer. I dive a unit with three cell logic and added a 4th cell merely because the 4 cell holder gave me independent monitoring of the cells (I had a bad 2020 handset experience).

    If a cell is 18 months old it is not worthy of trust and might be reluctantly trusted to #4 slot. However, all cells linked to the set-point controller must be under a year old. I just discarded a cell from the 052019 batch due to age. With the current O2 sensor supply issues I contemplated keeping it. I didn't.
    I was thinking about that earlier when I read the latest revo evangelical about scrubber life and scrubber monitors. The idea they have a simple time-based life is wrong unless you are just diving shallow. The split scrubber is pretty good idea and the Aurora Blue has similar, with a different physical implementation.

    My Inspo scrubber monitor aka tempstick is pretty reliable as a measure of scrubber function (didn't Mitchell to a test of this?) for shallower dives and I've run it far quite a long time beyond the '3 hour scrubber' (at least 6 hours). However, if I am doing something deeper,for the tiny incremental cost, I'll ditch the lime and go with a fresh fill. The lesson of the Zorg should not be ignored.
     
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  19. Wibble

    Wibble Fish don't talk
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    What is the Aurora Blue? Never heard of that one before and can't find the manufacturer's website. Does it exist as a product?

    Whilst Zorg exists (as in the greater size of the reaction front in CO2 absorbent at depth), this isn't relevant for the max 45m diving I'll be doing for a while and I've no intention of begging bother by maximising scrubber life.

    Incidentally after the first scrubber's consumed, the estimated life of the second scrubber is greatly reduced as margins for safety are added. As the second scrubber has a temperature probe, the reaction front will be quickly detected once it moves into the second scrubber.
     
  20. Dave Whitlow

    Dave Whitlow Super Moderator
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    Aurora Blue is a project that was run by Michael Hearm which was shown at Eurotek with Narked@90. You can see pictures on this RBW (need to login for the pictures).

    http://www.rebreatherworld.com/showthread.php?44122-aurora-blue&

    Only a few were ever made but I dived with one of their owners until I departed from the southeast. He sold his Revo as it was too heavy for thin wetsuit diving for his trip to Bikini. The owner of the Revo remains happy with it.

    Those without a scrubber monitor throw away more lime than they need but they have no basis on which to make an alternative decision.

    You'll get a feel for scrubber life. I watch the temptick on my Inspo and it is good to have a feel for what is going on in the scrubber.

    You'll find when you do those 45m dives a lot more of the scrubber will be active as the Zorg miss the CO2 and it penetrates further through the lime. When you get shallow again you'll see a small area of lime is active.

    Well done in finally dumping those big heavy bottles and dropping the helium-wasting habit.I doubt you will regret the decision to go CCR.
     

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