cell testing

***Beanie*** · 7th April 2005, 09:53

any cunning ideas on how to verify cells are good without getting the unit wet?

other than checking that you get ppo2 1.00 at 100% loop and ppo2 0.21 at 21% loop and that the cells are within spec.

***schford*** · 7th April 2005, 09:55

Can you read the milivolt output of the individual cells?

On the megalodon one of the tests is to check in real time what your mini volt output is - in air if its below 8 you need to change it.

Also means if you have a sensor being voted out on the dive you can quickly check the mini volt outputs to make sure that it really is faulty and that 2 faulty cells are not voting it out.

stuart

***Beanie*** · 7th April 2005, 09:59

Quote: (Originally Posted by schford)

Can you read the milivolt output of the individual cells?

yep the same you can read the output of the cell in air has to be between 8 and 13mV

peter · 7th April 2005, 11:41

Its possibly to ”short-circuit” the scrubber and check the sensors at overpressure.
So that you can see that they are working up to 1,4-1,5 PO2.

I think it is explained in the manual...

Padowan · 7th April 2005, 12:30

Quote: (Originally Posted by Beanie)

any cunning ideas on how to verify cells are good without getting the unit wet?

other than checking that you get ppo2 1.00 at 100% loop and ppo2 0.21 at 21% loop and that the cells are within spec.

How long do you leave the unit at 1bar filled with O2? I fill mine up about once a month and leave it for a good few hours on Low SP after a REALLY good O2 flush. If there's any drop from 1 bar then the cells are probably "running out of juice" and this effect will be excasserbated when trying to hold 1.3bar for long periods as the mV output will need to be higher..... learnt this trick from someone else, so can't claim credit for it!!

I also keep track of my calibration millivoltages by noting down the 2 readings just before is goes "CALIBRATING" I can then track is any one cell is starting to drop it's output over time.

Padowan · 7th April 2005, 12:32

Quote: (Originally Posted by peter)

Its possibly to ”short-circuit” the scrubber and check the sensors at overpressure.
So that you can see that they are working up to 1,4-1,5 PO2.

I think it is explained in the manual...

Is the scrubber can rated for a bar and a half working pressure? I'd not want to risk fracturing, warping or damaging it possibly?

***Beanie*** · 7th April 2005, 12:47

Quote: (Originally Posted by Padowan)

How long do you leave the unit at 1bar filled with O2? I fill mine up about once a month and leave it for a good few hours on Low SP after a REALLY good O2 flush. If there's any drop from 1 bar then the cells are probably "running out of juice" and this effect will be excasserbated when trying to hold 1.3bar for long periods as the mV output will need to be higher..... learnt this trick from someone else, so can't claim credit for it!!

er about 1/2 hour last night

Quote: (Originally Posted by Padowan)

I also keep track of my calibration millivoltages by noting down the 2 readings just before is goes "CALIBRATING" I can then track is any one cell is starting to drop it's output over time.

I have somewhere the value mine where at when they were new but I am buggered if I can find it funny thing is neither can Paul or Lisa who did the same at the same time sure I wrote them in the manual.

my current cells (original 18 months old 95hrs) are at just below 1 ~0.98
seem to remember new they were 1.3 ish

Padowan · 7th April 2005, 13:19

Quote: (Originally Posted by Beanie)

er about 1/2 hour last night

I have somewhere the value mine where at when they were new but I am buggered if I can find it funny thing is neither can Paul or Lisa who did the same at the same time sure I wrote them in the manual.

my current cells (original 18 months old 95hrs) are at just below 1 ~0.98
seem to remember new they were 1.3 ish

1.3, that's pretty high = 13mV. Mine were about 10.1-10.3 mV when new, and now currently at about 9.8-10.1mV during Calibration - my cell 2 has been consistently a few 1/10ths of a mV lower than cells 1 or 3 since the day the unit came out of it's crate.

Also for replacement cells, I would not order 3 at once. I'd space out 3 seperate orders out to ensure that you got 3 cells from different batches (or make this request to AP for 3 cells from different batches) so that a mfg error in one batch does not totally kill your units performance (and perhaps you)

***Beanie*** · 7th April 2005, 13:36

Quote: (Originally Posted by Padowan)

1.3, that's pretty high = 13mV. Mine were about 10.1-10.3 mV when new, and now currently at about 9.8-10.1mV during Calibration - my cell 2 has been consistently a few 1/10ths of a mV lower than cells 1 or 3 since the day the unit came out of it's crate.

hmm could be I know mine were high when new pretty sure they were 1.25 or something if I could find which manual I wrote it in it would help (Beanie 6 manuals)

Quote: (Originally Posted by Padowan)

Also for replacement cells, I would not order 3 at once. I'd space out 3 seperate orders out to ensure that you got 3 cells from different batches (or make this request to AP for 3 cells from different batches) so that a mfg error in one batch does not totally kill your units performance (and perhaps you)

not tought of that all I wanted was three matched cells

peter · 7th April 2005, 17:45

Quote: (Originally Posted by Padowan)

Is the scrubber can rated for a bar and a half working pressure? I'd not want to risk fracturing, warping or damaging it possibly?

Yes its no problem, but don’t forget to flush out the air…
But if you want to play safe don’t run it higher then 1,2 -1,3 PO2..
Didn’t find any info in the manual, but found this in the Inspiration list archives.

If the symptoms are that you get the cell errors only at 1.3 dsetpoint and
that they disappear att 0.7 you most likely have no problem with the
electrical connections but rather a cell that is loosing its linerity at the
high end. This is in my experince how a cell starts to fail.

You can test the cells at the high end by building your own "pressure pot"
with the scrubber.

basically..

-Assemble and calibrate the unit as normal and leave everything on at
setpoint 0.7.

-Take away the inhalation hose between the scrubber and T peice.

-disconnect the scrubber exhale hose at the T-piece and connect at the
center of the scrubber lid, In effect "shortening" the loop at the scrubber.

-Set the setpoint to 1.3. This will cause the solenoid to add O2 to the
scrubber and build up pressure until the PO reaches 1.3

-All sensors should now show 1.3.

-Leave the unit is this state for a couple of hours and you will see if any
of your sensors starts to drift.

-Change the drifting sensor.

Whatever you do do NOT CALIBRATE while you have "shortened" the loop. It
will blow up the scrubber!!!

This method that was given to us by Martin Parker has caught all my failing
sensors.

Best regards
Esse

7th April 2005, 09:53	#1 (permalink)
*Beanie* give a man an inch....... Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,174	cell testing any cunning ideas on how to verify cells are good without getting the unit wet? other than checking that you get ppo2 1.00 at 100% loop and ppo2 0.21 at 21% loop and that the cells are within spec. __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
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7th April 2005, 09:55	#2 (permalink)
*schford* Despotic Overlord Current Rebreather/s: Megalodon Sport Kiss Other Rebreather/s: Join Date: Jan 2005 Location: London, UK Posts: 3,562	Can you read the milivolt output of the individual cells? On the megalodon one of the tests is to check in real time what your mini volt output is - in air if its below 8 you need to change it. Also means if you have a sensor being voted out on the dive you can quickly check the mini volt outputs to make sure that it really is faulty and that 2 faulty cells are not voting it out. stuart
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7th April 2005, 09:59	#3 (permalink)
*Beanie* give a man an inch....... Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,174	Quote: (Originally Posted by schford) Can you read the milivolt output of the individual cells? yep the same you can read the output of the cell in air has to be between 8 and 13mV __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
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7th April 2005, 11:41	#4 (permalink)
peter New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2005 Location: Göteborg/Sweden Posts: 47	Its possibly to ”short-circuit” the scrubber and check the sensors at overpressure. So that you can see that they are working up to 1,4-1,5 PO2. I think it is explained in the manual... __________________ Peter
(Online)

7th April 2005, 12:30	#5 (permalink)
Padowan Proper Boffin Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Kent, UK. Posts: 518	Quote: (Originally Posted by Beanie) any cunning ideas on how to verify cells are good without getting the unit wet? other than checking that you get ppo2 1.00 at 100% loop and ppo2 0.21 at 21% loop and that the cells are within spec. How long do you leave the unit at 1bar filled with O2? I fill mine up about once a month and leave it for a good few hours on Low SP after a REALLY good O2 flush. If there's any drop from 1 bar then the cells are probably "running out of juice" and this effect will be excasserbated when trying to hold 1.3bar for long periods as the mV output will need to be higher..... learnt this trick from someone else, so can't claim credit for it!! I also keep track of my calibration millivoltages by noting down the 2 readings just before is goes "CALIBRATING" I can then track is any one cell is starting to drop it's output over time. __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
(Offline)

7th April 2005, 12:32	#6 (permalink)
Padowan Proper Boffin Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Kent, UK. Posts: 518	Quote: (Originally Posted by peter) Its possibly to ”short-circuit” the scrubber and check the sensors at overpressure. So that you can see that they are working up to 1,4-1,5 PO2. I think it is explained in the manual... Is the scrubber can rated for a bar and a half working pressure? I'd not want to risk fracturing, warping or damaging it possibly? __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
(Offline)

7th April 2005, 12:47	#7 (permalink)
*Beanie* give a man an inch....... Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,174	Quote: (Originally Posted by Padowan) How long do you leave the unit at 1bar filled with O2? I fill mine up about once a month and leave it for a good few hours on Low SP after a REALLY good O2 flush. If there's any drop from 1 bar then the cells are probably "running out of juice" and this effect will be excasserbated when trying to hold 1.3bar for long periods as the mV output will need to be higher..... learnt this trick from someone else, so can't claim credit for it!! er about 1/2 hour last night Quote: (Originally Posted by Padowan) I also keep track of my calibration millivoltages by noting down the 2 readings just before is goes "CALIBRATING" I can then track is any one cell is starting to drop it's output over time. I have somewhere the value mine where at when they were new but I am buggered if I can find it funny thing is neither can Paul or Lisa who did the same at the same time sure I wrote them in the manual. my current cells (original 18 months old 95hrs) are at just below 1 ~0.98 seem to remember new they were 1.3 ish __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
(Offline)

7th April 2005, 13:19	#8 (permalink)
Padowan Proper Boffin Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: Kent, UK. Posts: 518	Quote: (Originally Posted by Beanie) er about 1/2 hour last night I have somewhere the value mine where at when they were new but I am buggered if I can find it funny thing is neither can Paul or Lisa who did the same at the same time sure I wrote them in the manual. my current cells (original 18 months old 95hrs) are at just below 1 ~0.98 seem to remember new they were 1.3 ish 1.3, that's pretty high = 13mV. Mine were about 10.1-10.3 mV when new, and now currently at about 9.8-10.1mV during Calibration - my cell 2 has been consistently a few 1/10ths of a mV lower than cells 1 or 3 since the day the unit came out of it's crate. Also for replacement cells, I would not order 3 at once. I'd space out 3 seperate orders out to ensure that you got 3 cells from different batches (or make this request to AP for 3 cells from different batches) so that a mfg error in one batch does not totally kill your units performance (and perhaps you) __________________ Padowan The future's bright, the future's Yellow .....for now padowan.net - Latest Video: Scapa Flow Rebreather Diving
(Offline)

7th April 2005, 13:36	#9 (permalink)
*Beanie* give a man an inch....... Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,174	Quote: (Originally Posted by Padowan) 1.3, that's pretty high = 13mV. Mine were about 10.1-10.3 mV when new, and now currently at about 9.8-10.1mV during Calibration - my cell 2 has been consistently a few 1/10ths of a mV lower than cells 1 or 3 since the day the unit came out of it's crate. hmm could be I know mine were high when new pretty sure they were 1.25 or something if I could find which manual I wrote it in it would help (Beanie 6 manuals) Quote: (Originally Posted by Padowan) Also for replacement cells, I would not order 3 at once. I'd space out 3 seperate orders out to ensure that you got 3 cells from different batches (or make this request to AP for 3 cells from different batches) so that a mfg error in one batch does not totally kill your units performance (and perhaps you) not tought of that all I wanted was three matched cells __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
(Offline)

7th April 2005, 17:45	#10 (permalink)
peter New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2005 Location: Göteborg/Sweden Posts: 47	Quote: (Originally Posted by Padowan) Is the scrubber can rated for a bar and a half working pressure? I'd not want to risk fracturing, warping or damaging it possibly? Yes its no problem, but don’t forget to flush out the air… But if you want to play safe don’t run it higher then 1,2 -1,3 PO2.. Didn’t find any info in the manual, but found this in the Inspiration list archives. If the symptoms are that you get the cell errors only at 1.3 dsetpoint and that they disappear att 0.7 you most likely have no problem with the electrical connections but rather a cell that is loosing its linerity at the high end. This is in my experince how a cell starts to fail. You can test the cells at the high end by building your own "pressure pot" with the scrubber. basically.. -Assemble and calibrate the unit as normal and leave everything on at setpoint 0.7. -Take away the inhalation hose between the scrubber and T peice. -disconnect the scrubber exhale hose at the T-piece and connect at the center of the scrubber lid, In effect "shortening" the loop at the scrubber. -Set the setpoint to 1.3. This will cause the solenoid to add O2 to the scrubber and build up pressure until the PO reaches 1.3 -All sensors should now show 1.3. -Leave the unit is this state for a couple of hours and you will see if any of your sensors starts to drift. -Change the drifting sensor. Whatever you do do NOT CALIBRATE while you have "shortened" the loop. It will blow up the scrubber!!! This method that was given to us by Martin Parker has caught all my failing sensors. Best regards Esse __________________ Peter
(Online)

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