A little Problem with one of my cells

anton610

Hello!

I think one of my cell is a little bit crazy!

Everything is normal when i calibrate my unit.
After half an hour of diving, my third cell tells me a ppO2 that is 0,03 - 0,09 times higher than the others
For example: 0,68 0,69 0,75

Had anyone the same problem?

What can i do?

Best Regards anton

__________________
"Das Übel kommt nicht von der Technik, sondern von denen, die sie mißbrauchen."

Jacques-Yves Cousteau (1910-1997)

kieranu

I get that happening from time to time with the Meg - could be water on the sensor. Have you tried a dil flush to see if that helps?

anton610

I'll try a dil flush but i think it doesn't help...

because i had it the last 6 dives


regards!

__________________
"Das Übel kommt nicht von der Technik, sondern von denen, die sie mißbrauchen."

Jacques-Yves Cousteau (1910-1997)

PhilSiswick

Hi Anton,

How old are the cells? My first set is about 10 months old now and their behaviour has changed a lot. At the beginning, they were very lively, now they are much more stable. However, at the weekend, cell 3 was reading a little higher (0.2) than cells 1 and 2. I didn't dil flush, as it wasn't a problem, but it was happening.

I'd suspect water on the cell, or the cell coming towards the end of its life are the causes. There was a thread last week that talked about cells failing high, as well as low, so this could be a sign of that. If you change the positions of the cells, you'd be able to determine whether it was the cell (i.e. age or a fault) or the location (i.e. water) that was causing the problem.

HTH,

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Phil (WSKD 0001)

I have always felt that the dive I am on is not nearly important as the dives I plan to be on the rest of my life. Tom Rose, 2007

The person who gets the farthest is generally the one who is willing to do and dare. The sure thing boat never gets far from shore. Charles A. Lindbergh

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nigelh

Chuck it out?

Cells, batteries and scrubber.
Anything else we can probably work round.

__________________
nigelh

pabusk

Isn't Cell3 the one pointing downward when in horizontal position. I had problems showing low PPO2 on cell 3 due to water on the sensor only during a second dive when the unit had layed on it's back without venting the head between dives.

Cheers,
Paul

AD_ward9

Your cell has a leak. Electrolyte is leaking out, or has leaked out. That is why cells read high after cal.

Replace it.

Water on the faces causes cells to read slow and low, not high.

Alex

Depth-junkie

1 reading 0.75 and the others reading 0.69 and say 0.68 Surely they are within tolerance as all three are indicating the pp02 to be around 0.70 to 0.75

I would be more worryed if they all read excatly the same all the time. If 1 read .90 and the others .70 then i would be worryed.

As suggested swap the cell positions and see how it goes.

To give you an example i currently have 1 new cell in position 1 and cell 2 and 3 are 11 months old (just about to be changed out next month)

on a dive they all read 0.03 within each other, but durring deco (usually by the the 45min to the hour mark of use) cell 1 drifts 0.05 to 0.10 from cell 2 and 3 (I.E 1.23, 1.3, 1.32) this drift dont worry me as they are all giving figures in the ball park and are not drifting enough to give a cell error. All cells are tested at the start of the dive to make sure non are current ltd and reach 1.5-1.6, so i am happy.

ATB
Gareth

AD_ward9

The issue is whether it has gone high after a cal, with respect to the others and the original cal.

The only reasons we have ever seen a sensor go high after its original cal, or with respect to a reference group of sensors, is:
1. The internal load resistor has failed. That is not the case here.
2. Loss of electrolyte. This happens easily if the sensor is dropped: electrolyte comes through the front membrane, and if the drop is big enough, though the internal seals. When this happens, even though the error may be very small, the cell is on the way out.

It is worth checking the reading of the fault is correct, i.e. the cell is genuinely high with respect to both its cal and the other cells. If that is true, only one conclusion is available as far as I am aware (I would be happy to be corrected if anyone has any other data).

Alex

PeteS

Cell drifting? Change it!

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Pete S.

http://www.steggle.co.nz

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