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Thread: Chain of events: break it!

  1. #11
    RBW Member IainC is an unknown quantity at this point IainC's Avatar
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    Inspiration Vision

    Re: Chain of events: break it!

    Thanks for the post, glad yo uwere able to sort it out with no hurt to you.

    It is a lot to remember when you are first using the unit!

    I also have had to stop and take apart my unit after a failure just before a dive - the pressure is high then, but you start a good habit to resist it and either fix the issue calmly or sit out the dive.

    This makes more sense.
    I'm only used to the old battery compartment, never opened or seen the new compartmnet with 2 x 2 button type batteries.
    So there's a new failure-point with the new battery compartment.
    This makes me want to keep my old style battery box even more - only two batteries.

  2. #12
    RBW Member fsardone is an unknown quantity at this point fsardone's Avatar
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    Re: Chain of events: break it!

    In the Vision HW there are 3 styles batteries:
    OLD CRP2 which had a single cover/single point of failure
    New CR123 B1 and B2 is made up by two CR123 (total 4) and each pair is sealed in a water tight o'ring sealed compartment.
    New rechargeable battery pack.

    CR123 are about half length of an AA battery, a bit fattier and their voltage is 3v

    I have style 2.
    Under time pressure, with the partly assembled head, in replacing the battery I tilted the head and the weight of the cells was not sufficient to make them fall out. So I pulled and therefore I pulled only the top one.

    I was warned during startup that B1 (being now made by a new cell and a spent one) was not full: 2 squares rather than the 3 I was expecting but I did not pause to ask myself why the cell that made up B2 and showed 3 squares would now show just 2 once moved in B1. Then I did not analyse why after diving for half an hour it went down to just 1 square and finally gave up with no squares.

    The reason I could not silence the alarm was because I need to press for 2+ seconds the right button of the hand set.
    The handset was on my left wrist and my right hand was on the line unable to let go since I was in a 0 vis silt out and I was leading the group ...I was out of hands.

    I would say the alarm is warranted because you have lost redundancy on your power supply and you are heavily draining the single battery left.
    It might be time to switch off continuously on backlighting or even run the rebreather on low set point and maintain PPO2 manually saving the solenoid power.

    Cheers

    Fabio
    Last edited by fsardone; 6th May 2015 at 13:19.

  3. #13
    RBW Member Sully has a spectacular aura about Sully has a spectacular aura about Sully has a spectacular aura about Sully has a spectacular aura about Sully has a spectacular aura about Sully's Avatar
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    Re: Chain of events: break it!

    Ok Fabio , I get it now. I also dive the old style batteries ( x 2 ) , what you are saying is the newer x 4 123s are in there holders / compartment one on top of the other . So when you removed them only the top battery came out , and because this was your first change you thought you were replacing B1 with B2 and then putting the new cell in B2 .
    Well done for the post mate.
    And put it down to one you will remember .
    On mine if the battery in B2 is getting down to 5.6ish I'll change them both £7 each , and both controllers are happy

  4. #14

    Re: Chain of events: break it!

    Yes, those batteries drop off quickly.

    Have a look at google for some of the battery discharge curves (link, although not exactly the recommended energizer). The more current they draw, the flatter the curve. The battery indicator can only measure the voltage (y axis), which is even more difficult in changing thermal conditions. Combine these factors and you will get a few dives where the unit calibrates lovely with three indicators on B1 only to fall to zero and beep when you jump in.

    I had this a few times and have now an item on my checklist to change the batteries in B1 when it is at 5.4V during the setup. When above this level, I never had an issue with a long dive or shorter double dives the day after setup (setup calibration, calibration on the day and leaving on thereafter). Below that level I ended up seeing B1 drop to one indicator, which is where I start to get slightly nervous. I guess you have to find your own level for that purpose.

    The biggest consumer is the solenoid. The more you fly manual, the longer the batteries will last as well. Especially at 40m I would almost change the high set-point to 1.2 and keep it manually at 1.3 to save batter with not too many injections needed. I also keep the unit on between dives as the solenoid opens quite often during switching on and calibration.

    At the end of the day, two new batteries cost $10 at most and this is due after maybe 10 dives, so $1 per dive. I am willing to spend that much for peace of mind!

    Hope that helps a bit. Happy diving!

    Edit: AP also has a rechargeable battery block now
    Last edited by ChrissR; 8th November 2015 at 13:31. Reason: Added link to AP

  5. #15
    RBW Member Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike has a reputation beyond repute Drmike's Avatar
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    Re: Chain of events: break it!

    Quote Originally Posted by fsardone  View Original Post
    I am sharing this to highlight how a simple (stupid?) mistake might severely impact a dive and end up in a quite serious situation.

    Yesterday I went to a lake (Lago di Bracciano) near Rome because sea was bad and I wanted to get wet in order to build time on my Inspiration. I am a new driver and while I am a cave, solo, hypoxic trimix diver OC, I am a 10 hour Air-dil deco CCR driver. So off we go.

    After building the machine at home, drove to the lake I meet with a group of friends all doing advanced Nitrox final dive for certification except the instructor who is sometime my buddy and let me join the group for the dive. While the instructor is a Megalodon driver, today I am the only one in CCR.

    There I calibrate redo my pos and neg pressure tests and happy with it I turn of the electronics and wait for everybody to get ready. After about half hour the instructor asks me if I was willing to do an initial dive to go set the buoy for the deco station setup for the students. I was happy to oblige since this would give me the chance of doing some more than expected and build quality time.

    So I put on my drysuit (it is already quite warm out but the lake is 10 C, so being dry with the full protective clothing on is not nice …) and I switch on the reb for donning it. Surprise, surprise, battery1 fails self test. Dive now? The electronics says. I had been tempted to say yes, we were ready to go in the cool water, I have a second battery which can drive the whole thing and the solenoid why not! And I actually say yes (not sure if only to see what would the machine do): the thing switches off!

    Well, it stops there and then, tell everybody I need 10 minutes delay, open up the reb and replaced B1 with B2 and put one new CR123 in B2. Yes ONE! Let me explain for the non Inspiration/Vision drivers. The machine has two sealed compartments which hold 2 CR123 batteries. Fact is that yesterday gravity force was not enough to make the battery fall out of the compartment and I put fresh batteries in the machine only once about 2 months ago before my course. So what I actually did was putting the top B2 battery on the bottom B1 battery (used up). Switch on and now the vision sw passes battery self test, great! But strangely enough with 2 battery squares in B1 rather than the 3 the same (I tought at the time) B2 used to have. Time to dive.

    The dive: 40 meters, limited visibility in the first. In the second with the student near the bottom, zero visibility and following the line out and back to the descent line to the deco station, it looked to me I was doing cave again! So I turn the console back light to always on. Bang on 2 minutes later B1 battery warning with buzzer and HUD flashing at me. Could not let go of the line at that time ended up annoying the whole lot until in deco I could silence the bugger.

    So:
    Battery went dead on surface (should happen once in a while)
    Diver half replace it (should not happen ever: once you know there are 2 I knew but forgot in the heat of the battle–I wont forget now!)
    Diver goes diving (we hope it happen often )
    Diver end up zero vis and switch backlight on (additional strain on batt)
    Diver end up on B2 driving the whole lot.

    This chain of events did create a non issue (using B2) thanks to redundancy and good design of vision HW and SW. But consider:

    Diver goes diving with only one battery (willingly giving up redundancy)
    That battery for some reasons goes belly up (continuous light on or cold or cap not screwed up correctly)
    Diver is without electronics and maybe task loaded: this per se is not an accident but it is a good set up for one.

    Bottom line:
    - Break up the chain of events at the earliest possible point: (correctly) replace battery or do not go diving.
    - Carry essential spares: had I not have a replacement battery at hand I might have gone diving only with B2!
    - Know your system: nothing to add here: my fault!

    Hope this helps somebody else avoiding my mistake (or a similar one for the matter).

    Cheers

    Fabio
    I found that tasks like tying on (on all but deep dives) are best done on OC. the reason being wob is lower and you can concentrate on working rather than monitoring the rb. Exception would be if your going to tie on and then do your dive.

    cold scrubber + working hard straight away on high focus/exertion task like pulling down line dragging it around fighting current and tying on is recipe for disaster imho. if air dive depths id throw on a tank to tie on.


    on rb during short moments of very high task loading when i really couldnt monitor well i would run scr by nose venting and manual dill inject (depth) manual o2 inject (above 6m) and dont worry so much what the unit is doing during short moments of high task loading

    on deco to stop annoying others you could have turned off unit and run scr or simply used your bail gas
    Last edited by Drmike; 25th November 2015 at 02:05.

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