Forth Cell in the head

[Mark Chase]

Forth Cell in the head


I was thinking about this option and wondered if there are any down sides to doing it this way. I appreciate it makes the return hose and the 02 feed more difficult to get at but it looked a lot neater than the Y piece and I am told there is less difference on the cell readings using this option.

Before I take the cordless to the head has any one got any comments?

ATB

Mark Chase

[Fathoms Down]

Originally Posted by Mark Chase

Before I take the cordless to the head has any one got any comments?

The engineer in me says that this is the best way to go and its a pitty that AP don't do it as an option. The same small voice also grumbles that its a pitty that DeltaP don't offer a CO2 monitoring option so you could stick one of those cells in as well.

Ah well, in a perfect world....

I'm sure I don't need to say that, if you are going to put the fourth cell in the head then make sure the connector is fully waterproofed once you've fitted it!

[MartinS]

Mark

The RB diver I mentioned in my try-dive post had this, and, as you said, he stated that he got much better readings than he'd had when it was in the y-piece. Am happy to ask him if there is any points to be noted/additional info when I see him tomorrow evening - let me know.

Regards, and dive safe

Martin

[Mark Chase]

Originally Posted by MartinS

Mark

The RB diver I mentioned in my try-dive post had this, and, as you said, he stated that he got much better readings than he'd had when it was in the y-piece. Am happy to ask him if there is any points to be noted/additional info when I see him tomorrow evening - let me know.

Regards, and dive safe

Martin

All help gratfully received so I would like very much to here his opinion.

ATB

Mark Chase

[Adrian Kelland]

If by 'head' you mean the lid section of the scrubber (I know nothing) the owner of Sandford and Down has the 4th cell in the head. He was able to get hold of a 'blank' lid to drill out 4 holes to arange the 4 cells radially.

Adrian

[turbanator]

Was there not a post on here a couple of weeks ago where someone described getting a 'blank' head and staggering the height of the cells to get 4 in?

[NotDeadYet]

Why not use a small cell like the K1D? They are about half the size of the R22D but still output 10.5mV in air. Not much different in price. I think that's what Gordon put in the travel KISS.

For good cable glands try Rapid Electronics, I got some from them which are rated to 150m. Only about £1 each. If you f**k it up, Plumber's epoxy is good for sealing the hole up, I did this on my Ray scrubber.

[NotDeadYet]

Just thinking, why add a 4th cell to the head anyway? If you've got three there to start with, why not take a feed off one of them, out through a gland and into the VR3?

[nigelH]

Originally Posted by NotDeadYet

Just thinking, why add a 4th cell to the head anyway? If you've got three there to start with, why not take a feed off one of them, out through a gland and into the VR3?

Probably impedance matching. The cell wants to see 10K hence I think both the VR3 and the Turtle provide that. Actually the cell can run into less (very low internal impedance) so parallelling up another probably wouldn't make much odds but....
I fancied taking all three, through their own 100K resistors out to a socket I could put my own electronics into. I can't see the worth in adding a fourth cell to the equation - if things start going wrong I've lost my consensus so I don't know who to trust so I'm outa-dare asap.

nigelH

[NotDeadYet]

Fair enough, electronics isn't one of my talents. Breaking electronics however...