Cell output

Scubascooby · 6th February 2007, 12:16

I've been using my home made Nitrox anayser for about 5 years without problems, I even made a few for some friends.

I opened a new Max250e sensor before Xmas but it wouldn't calibrate to air. On some of the units I had an internal trimmer to change the range but on my own I had left it out for soem reason. So I left it until now.

To cut a long story short. I swapped one of the resistors to change the range but the sensor output had climbed to 14.5mV by the time I had done it, about 24hrs after initially testing it.

So with the meter reading about 21.9 in air I tested some oxygen and could only get it up to 97%ish

Does this sound like a duff cell ?

**jstovall** · 6th February 2007, 17:45

Where are you getting your O2? Some supplied o2 from distributors may only be 96-99%. Did you cross check with another analyzer?

Scubascooby · 7th February 2007, 12:25

I have considered that. I could cross check using the KISS I suppose
or borrow an analyser from a mate.

Sutty · 7th February 2007, 16:50

You could try pressurising it a little - even squeezing a plastic bag full of O2 with the cell in should raise it a little to demonstrate that you haven't reached the cells current limit (ie it really is 97%).

Neil

6th February 2007, 12:16	#1 (permalink)
Scubascooby Better Off Out of the EU Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Nov 2005 Location: Great Britain Posts: 387	Cell output I've been using my home made Nitrox anayser for about 5 years without problems, I even made a few for some friends. I opened a new Max250e sensor before Xmas but it wouldn't calibrate to air. On some of the units I had an internal trimmer to change the range but on my own I had left it out for soem reason. So I left it until now. To cut a long story short. I swapped one of the resistors to change the range but the sensor output had climbed to 14.5mV by the time I had done it, about 24hrs after initially testing it. So with the meter reading about 21.9 in air I tested some oxygen and could only get it up to 97%ish Does this sound like a duff cell ? __________________ "dove" is NOT the past tense of "dive" Better off OUT of the EU ! www.hugsac.org.uk
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6th February 2007, 17:45	#2 (permalink)
jstovall Supporting Member Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Apr 2006 Location: New Braunfels, TX Posts: 55	Re: Cell output Where are you getting your O2? Some supplied o2 from distributors may only be 96-99%. Did you cross check with another analyzer?
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7th February 2007, 12:25	#3 (permalink)
Scubascooby Better Off Out of the EU Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Nov 2005 Location: Great Britain Posts: 387	Re: Cell output I have considered that. I could cross check using the KISS I suppose or borrow an analyser from a mate. __________________ "dove" is NOT the past tense of "dive" Better off OUT of the EU ! www.hugsac.org.uk
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7th February 2007, 16:50	#4 (permalink)
Sutty Classic Kiss diver Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Jun 2005 Location: Glossop, Derbyshire, UK Posts: 800	Re: Cell output You could try pressurising it a little - even squeezing a plastic bag full of O2 with the cell in should raise it a little to demonstrate that you haven't reached the cells current limit (ie it really is 97%). Neil __________________ Never forget that life is a finite resource.
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