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Thread: a snake in my save- a- dive kit!!!

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    hell is in the details Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T is just really nice Marc T's Avatar
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    EDO04 Ray

    a snake in my save- a- dive kit!!!

    Wake up lazzy people, cool down others no snake, just a small well known evil
    Everybody know the benefit of cell checker...

    Built a nice one designed for p port as all my sensors are on p port plug but I use just from time to time.

    Last night tested, but why, my SAD- kit- solo sensor and pure O2 at one bar 98, air 22 ooookay.

    Today took this same sensor in order to mix gaz with my gas blender and had ( fortunatly ) an erratic value on air, tested several system, tested all the connector, tested on O2, tested the sensor on voltmeter and the result is.....
    sensor give a différent value depending on the position: sensor face upside 13mV, face down 10 mV.

    So put the little bastard in the cell checker on pure O2 got 1 at 1 bar, 1.5 at 2 bar and 2 at 3 bar .

    Every rebreather diver must have a cell checker and use it on a regular basis

  2. #2
    Normal people worry me jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap is a name known to all jaap's Avatar
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    Re: a snake in my save- a- dive kit!!!

    Quote Originally Posted by Marc T  View Original Post
    Wake up lazzy people, cool down others no snake, just a small well known evil
    Everybody know the benefit of cell checker...

    Built a nice one designed for p port as all my sensors are on p port plug but I use just from time to time.

    Last night tested, but why, my SAD- kit- solo sensor and pure O2 at one bar 98, air 22 ooookay.

    Today took this same sensor in order to mix gaz with my gas blender and had ( fortunatly ) an erratic value on air, tested several system, tested all the connector, tested on O2, tested the sensor on voltmeter and the result is.....
    sensor give a différent value depending on the position: sensor face upside 13mV, face down 10 mV.

    So put the little bastard in the cell checker on pure O2 got 1 at 1 bar, 1.5 at 2 bar and 2 at 3 bar .

    Every rebreather diver must have a cell checker and use it on a regular basis
    Indeed, I test my cells too in my little pot to 2 bar o2 on a regular basis (not before every dive though).

    I have also had the position dependent error once on one cell, quite nasty actually, if pitched around 45 degrees in the long axis it would change its reading by about 30%. Extra nasty, if stationary it would remain ~linear up to po2 2,0

    In its defence the cell was over one year in when I noticed this (and discarded it from further use).

    I also noticed that some cells would pass calibration and the pot test at room temp but would fail if the same test was performed within hours when the cells and electronics was at equilibrium in about 8 C (not so strange, low temp affects the chemistry just like most batteries, actual loop temp it also usually higher also in cold water, but it can give dangerous transient effects)

    To stay safer I now prefer to use 4 cells (not always), regular pressure pot checks, try to check for both temp/position effects while in the pot. I also avoid any excessive vibration to the cells (such as from dropping them, watch out if you do). Of course this in addition to the regular in dive checks that they all give the same respons at depth (have them spread on inhale & exhale side).

  3. #3
    RBW Member Franck13 is an unknown quantity at this point Franck13's Avatar
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    kiss poseidon lard ....

    Talking Re: a snake in my save- a- dive kit!!!

    Quote Originally Posted by Marc T  View Original Post
    Wake up lazzy people, cool down others no snake, just a small well known evil
    Everybody know the benefit of cell checker...

    Built a nice one designed for p port as all my sensors are on p port plug but I use just from time to time.

    Last night tested, but why, my SAD- kit- solo sensor and pure O2 at one bar 98, air 22 ooookay.

    Today took this same sensor in order to mix gaz with my gas blender and had ( fortunatly ) an erratic value on air, tested several system, tested all the connector, tested on O2, tested the sensor on voltmeter and the result is.....
    sensor give a différent value depending on the position: sensor face upside 13mV, face down 10 mV.

    So put the little bastard in the cell checker on pure O2 got 1 at 1 bar, 1.5 at 2 bar and 2 at 3 bar .

    Every rebreather diver must have a cell checker and use it on a regular basis
    Marc i always say for electronic lessons or questions: Narkedat90 or if you want go to Space with your rebreather :Nasa scientific Baïkonour scientific Toulouse, the Chinese have too a Spatial program i believe

    Franck
    Last edited by Franck13; 12th November 2013 at 19:27.

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