Cell In Meg Counter Lung

Cell In Megalodon Counter Lung
By Si Lawrence


A quick write up about my attempt to fit a fourth cell mod to the inhalation counter lung of my Meg.


After a couple of UK dives and a weeks diving on it in the red sea it performed well we are not talking much testing 25 to 30 hours but it is a start. The cell tracked the Apecs software pretty close well as close as you can tell on a HS explorer since it only shows 1 decimal place on the computer display. Any thing from 1.25 to 1.34 will be shown as 1.3 and so on downloading to the pc I could see nothing out of the ordinary in the readings.

You did get some spiking on the cell when you manually injected O2 a reading of 1.3 would raise to around 1.6 but with in two to three breaths it was back reading 1.3 again. If the unit is left to run via electronics with the solenoid firing then it tracked the same with no spiking.

The hardest part of the build was removing the T piece connector from the counter lung so I could fit the P port.


For those of you who have been through the tech class at the ISC factory you will know of the term Leon Tight. Even Leon would have had fun removing this fitting. In the end the technique was heat up the connector, clamp the removal tool in a vice insert a small metal bar into the back of the t piece connector and with all your strength unscrew the fitting to break the silicon. Success!! Then it was the point of no return cutting a hole into a perfectly good counter lung knowing if it doesn’t work $660:00 is required to buy a new set of lungs. I hesitated for at least half a second before plunging the scissors through.

The cell when inserted sits with its face right under the inhalation counter lung T and directly in the gas path as you breathe off the loop. As for condensation on the cell I seemed to have less moisture at the end of the day on this cell than on any of the cells in the head.


The cell holder sits at a slightly upward angle so with the lung mounted on the harness you don’t even know it is there. I didn’t notice any affects it the WOB with the cell in this position a slight concern was it may cause a restriction in the gas path on the loop. That is not to say that if you put it on and ANSI machine then it may show an increase.


What I did find was I had to calibrate the cell every day on the Explorer otherwise I did notice a difference in what the cell would read. To get over the calibration and not use lots of gas to flush the loop the cheap side of my nature came forward and a little box was made. This allows me to calibrate the cell with the same technique as the head only calibration of the Meg.


As for really cutting time of your Deco it was clearing slightly quicker than the stand alone explorer but my two units are running on different software versions and never did match even when running on a fixed po2.

We have the diving season ahead and we shall see how it performs through out the year. For those of you who are wondering why I used a P connector? Simple I had it sitting around from my days of diving a Drager. And so it didn’t require any custom parts to be made and drager parts are easy to get.

I will also let Leon dive with the lung later this year when i see him and await his feed back.


Si Lawrence


Discuss this article HERE