Cell 3 Error, water on cell face

M

moose_grunt

Member
So, I just got back from a 7 day dive trip where I racked up 18 hours on my Evo. Almost every day, I finished at least one dive with a Cell 3 error, almost always during final ascent. The cell would become sluggish and couldn't keep up with the changing PO2 during ascent, but it would catch up once I hit deco stops. There was always water on the cell face. I put in a new cell, and still had errors. I switched cells around, and still had errors on the Cell 3 position, no matter what cell was actually there, ruling out a problem with the cell itself.

I assume it has something to do with my position in the water that is causing condensation to eventually drip on the cell face. Has anyone else had this problem, and tracked down specifically what causes it?

Thanks,
Jim
 
I've had the same thing with cell 3 on my Inspo Vision, but never really tried to work out why cell 3 as it's so obviously moisture and it clears as soon as a little dry gas hits the cell. If you work it out, please do post! I'll do likewise.


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If you have tried a new cell I would investigate wiring next. The connectors do get corroded.

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BjFaeTorphins said:
If you have tried a new cell I would investigate wiring next. The connectors do get corroded.
Click to expand...

I've considered wiring, but the connector shows no signs of corrosion. I also think a wiring problem would cause the cell to either not register at all, or give 0 or 2.55 readings. Thoughts?
 
I had cell readings when calibrating which maxed at 0.5 with wiring problems. I've also seen the cell drop to 0.6 in the water when the set point is at 1.3. Turned out to be wiring and connectors

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This is a known problem with inspos. At least on the older models, I don't know if they had a design change since I was looking at them. If you look at old RBW posts (circa 2007) there are threads on making blowers to clear the condensation off the cell face.

I had the same problem when I was diving an inspo as well. It typically happened if I was doing two dives/day on a more recreational schedule (so 1 hour-ish followed by a 1-2 hr surface interval and another hour dive) and didn't have a chance to open the head between dives to let it dry. Of course the bigger problem is that you start getting alarms at a certain point in the dive and after a while you "know" that it is just the slow sensor so you ignore the alarm. Bad news all around there. It was a primary reason for not sticking with AP for me.

-Chris
 
sea_ledford said:
This is a known problem with inspos. At least on the older models, I don't know if they had a design change since I was looking at them. If you look at old RBW posts (circa 2007) there are threads on making blowers to clear the condensation off the cell face.

I had the same problem when I was diving an inspo as well. It typically happened if I was doing two dives/day on a more recreational schedule (so 1 hour-ish followed by a 1-2 hr surface interval and another hour dive) and didn't have a chance to open the head between dives to let it dry. Of course the bigger problem is that you start getting alarms at a certain point in the dive and after a while you "know" that it is just the slow sensor so you ignore the alarm. Bad news all around there. It was a primary reason for not sticking with AP for me.

-Chris
Click to expand...

Thanks for that lead--I'll try to track down those posts, and see if there was a resolution. My unit was built in 2007, but seems to have been haphazardly upgraded (latest solenoid, but old (square) battery box), so it may have missed an upgrade that would fix that. There were 4 other inspos in the group and only mine had the problem, so it seems to be localized to my unit and not a rampant issue any more. Hopefully.

Jim
 
I'd be very interested to hear how you get on with this - my Evolution is a 2007 model and I haven't experienced the problems you describe (except for on odd occasions, usually right after doing something unusual like swimming on my back and so forth). Mine has been upgraded to the new solenoid and battery box (not the rechargeable version, the steel one) and the entire lid got replaced a while back as APD cracked the old one during servicing, so if you need to compare designs or whatever, I might be able to help. I have some vague recollection of hearing about a small screw/bolt head that was in the loop near where the cells were situated that could cause condensation to form and then drip onto cells but I might have got completely confused (I didn't make a note of whatever the discussion was about as my unit doesn't show the problem)...
 
Thanks! I also got a private message saying that someone used to have the same problem with their classic. Condensation apparently collected on a screw inside the loop (probably the screw that holds the battery holder in?) and dripped onto the cell face.

I've attached a picture of the screw holding the battery box in my unit. I have the new style old battery box (the square one that takes the big batteries, but has springs in it). I wonder if it is indeed that screw. In the group of Inspo divers I was with, only I had this problem. I was also the only one with the old battery box--everyone else had the round steel tubes. I'll take a look at their battery box screws next time I dive with them, but a new baby means that will be a while :(.



If anyone (JTurner!) wants to chip in with pictures/opinions, I'd appreciate it...
 
moose_grunt said:
Thanks! I also got a private message saying that someone used to have the same problem with their classic. Condensation apparently collected on a screw inside the loop (probably the screw that holds the battery holder in?) and dripped onto the cell face.

I've attached a picture of the screw holding the battery box in my unit. I have the new style old battery box (the square one that takes the big batteries, but has springs in it). I wonder if it is indeed that screw. In the group of Inspo divers I was with, only I had this problem. I was also the only one with the old battery box--everyone else had the round steel tubes. I'll take a look at their battery box screws next time I dive with them, but a new baby means that will be a while :(.



If anyone (JTurner!) wants to chip in with pictures/opinions, I'd appreciate it...
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I'll check mine when I get home in a day or so. If I haven't done so by Friday - nag the hell out of me (I've got a shite memory!).
 
Thanks. That would be a super easy fix if indeed it is the screw, and it just needs to be swapped out for a flat one.


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moose_grunt said:
Thanks. That would be a super easy fix if indeed it is the screw, and it just needs to be swapped out for a flat one.
Click to expand...

Checked it and mine looks... exactly the same! If you like, I'll email you a piccie of it (please send me an email address to post it to as I cannot get these forums to show any photos for some mysterious reason).

So, I'm not sure that helps much... I'll have a think and see if there's anything else that springs to mind. I take it you don't swim on your back or side, or ever leave the unit lying on it's back when the loop has been used, or have a leak or any other obvious potential causes?
 
If that screw mad a difference then everyone would always have cell errors.

More likely the cell or the wiring.

Rotate the cells and confirm if the problem moves or not.

Matt.
 
jturner said:
Checked it and mine looks... exactly the same! If you like, I'll email you a piccie of it (please send me an email address to post it to as I cannot get these forums to show any photos for some mysterious reason).

So, I'm not sure that helps much... I'll have a think and see if there's anything else that springs to mind. I take it you don't swim on your back or side, or ever leave the unit lying on it's back when the loop has been used, or have a leak or any other obvious potential causes?
Click to expand...

Thanks. Actually I was rolling around a lot on those dives, as I get through hatches with less banging about when I go sideways.

matt said:
If that screw mad a difference then everyone would always have cell errors.
Click to expand...

C'mon, let me hope and dream that it's an easy fix I can do myself...:uhh:

Rotate the cells and confirm if the problem moves or not.
Click to expand...

Problem didn't move. Is there any way to test the wiring? Connector doesn't look corroded, but I didn't see any way to actually get a DMM on the other end to check for resistance.

Thanks,
Jim
 
moose_grunt said:
Thanks. Actually I was rolling around a lot on those dives, as I get through hatches with less banging about when I go sideways.
Click to expand...

Probably paranoia on my part but I try to avoid that wherever possible: when I was doing my Mod1, I was advised to avoid leaving the unit lying on the yellow box, or doing excessive rolls or swimming on my back, as it can cause the condensation to roll round onto the cell faces. It might be worth looking for a pattern to see if that could be a cause?

Another one you might want to try if it is possible would be to move the cell and wire from 3 to 2, so the cell are mounted 132 instead of 123 (remember to put it back again at the end!) and see if cell 2 (position 3) starts playing up or if cell 3 (position 2) still causes you grief, as that might indicate the wiring/connector fault that the other chaps have been suggesting.
 
moose_grunt said:
Thanks. Actually I was rolling around a lot on those dives, as I get through hatches with less banging about when I go sideways.



C'mon, let me hope and dream that it's an easy fix I can do myself...:uhh:



Problem didn't move. Is there any way to test the wiring? Connector doesn't look corroded, but I didn't see any way to actually get a DMM on the other end to check for resistance.

Thanks,
Jim
Click to expand...

No way I know of of testing the wiring yourself without opening it up. I would guess if you cut the connector off you'll find there's been some electrolyte leak and the cable is black.
 
To drag this thread back into a slow death, I dove the unit again this weekend for the first time since the last post. Babies seem to do that to you (not to mention the new job and overseas move). Had the same problem. 83 degree water, cell 3 error on ascent (couldn't keep up) on both dives that day, water on cell 3 face.

Any other things to test before I cut the connector off and check the wire?

Jim
 
So you've swapped cells and the problem stayed - this eliminates the cells themselves.

Have you tried moving the cell cable to another position? If the error changes to the new cell/cable in position 3 you'll know it's condensation being a pain, if it moves to the new spot you'll be looking at black death in cable #3 with a lot more confidence.

As an aside, I don't have a lot of mind for all these claims of N@90 cells leaking electrolyte. I've seen plenty of coax cables die but have never seen an electrolyte leak. Copper + high pressure, 100% humidity air forcing moisture through a leak into the cable + a small voltage when cells are left connected = rot of the cable. And yes, the connectors can look perfect. For electrolyte to leak in such a way as to cause connector issues, the whole back of the cell would be caked in the stuff. And for it to cause issues with the cables would require more electrolyte to leak than actually exists within the cell.
 
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