Voltage Limited Cell

Freak214

Ok, had a strange problem over the weekend and I think it was due to a voltage limited cell... During a dive to about 120 fsw on a Draeger Dolphin using a 40% mix on the 60% orifice my VR3 registered a F02 of about 25%. With this mix/orifice my normal inspired F02 is about 30%-32%. I figured maybe I was swimming harder than I thought... so I flushed the loop a few times but nothing changed, the F02 was still at 25%. Since this ruled out a blocked orifice I figured I would just make it a short 10 minute dive and figure out the problem on the boat.

I kept a close eye on the VR3 during the ascent and at about 80 fsw my F02 started to climb. By 70 fsw it read 32% and by the hang bar with a flush it was reading 37%. These are the normal reading for me. For the next 3 dives I used the VR3 and an Oxyguage and compared the F02's of each gauge, sure enough anything deeper than 80 fsw and the VR3 started to drop off.

So here is the real question, is this how a voltage limited cell will react and is there any way to test a cell without building a pressure pot?

Thanks
JohnL

E-man

you only need 8.82 psi to simulate 1.6 ata

jaap

If you have 100% O2 and a voltmeter you can get a hint if the cell is going hold. Check the mV reading in air, then put the cell in a bag and flush it with 100% O2 or flush O2 over the cell reading the mV.

The output in mV should be a factor ~4,78 higher in 100% O2. If its considerably lower well then you know the cell is getting to old.