Any impact from a vacuum on leak/moisture detectors and batteries?

[Incident]

Hi All,
I was reading the other thread about vacuum sensors and a thought crossed my mind (I figured I would start this thread instead of hijacking the other one).

Can anyone think of any reason that creating a vacuum in a housing which also contains a moisture sensor would increase the risk of the battery exploding (or leaking) from either the moisture sensor (usually a small button type battery) or the battery of the camera itself?

I have no idea if a battery is inherently vulnerable to expansion or rupturing due to being placed into a vacuum, but the thought crossed my mind and I figured I would ask.

I have not heard of this happening, so assume it is not a risk, but was curious to get thoughts from the group.

Thanks!!

 

[spoolin01]

Interesting question. How much vacuum are you considering? A psi or two? I would think some tolerance would be engineered in since ambient pressure fluctuation is a fact of life. Capacitors in the camera might be an issue as well.

Maybe you can find out what NASA uses.

 

[Incident]

I'm actually only thinking of the vacuum that is needed to get any one of the various leak sensors to function. Not sure how much or little of a vacuum that is though. The products such as Sentinal, Nauticam, etc., which require a vacuum to be created and therefore give a visual okay to let the diver know there is not a leak.

Again, I have not heard of any issues, but I was just curious if the creation of a vacuum in a housing to prevent one issue (water incursion) is opening the door to the potential creation of a different one (battery damage).

 

[bvanant]

Many of the modern vacuum sensors are also leak detectors (like the Nauticam). The working pressure is only 150 mB or so below ambient so there will be no noticeable effect on batteries or any other components. Thousands of divers on hundreds of thousands of dives with no issues so far. Hard to figure out the physics of what might change in a battery at -150 mB or so.
Bill

 

[tursiops]

The device to pull the "vacuum" on the Nauticam appears to be the same as the one you use on a wine bottle for storage of a partially finished bottle.
The "vacuum" is therefore a very small drop from ambient! I'd estimate just 2-3 psi, based on how hard it is to open the case if the pressure is not relieved, which is consistent with the 150mB in the post above. There is a much larger pressure drop just by going to altitude, like on a decent mountain or on a plane....and batteries do not explode in those places.

If I wanted to worry about something I'd be more worried about the increased pressure-difference across the o-ring and gasket seals....but that is not a problem either. Seeing that green LED shining at me as I descend and during the dive is incredibly comforting!

 

[bvanant]

One important point to note that if you do dislodge something and some water does indeed get in, the green light will be still shining, since a small amount of H2O will not measurably increase the pressure to make the red light go on.
Bill

 

[tursiops]

One important point to note that if you do dislodge something and some water does indeed get in, the green light will be still shining, since a small amount of H2O will not measurably increase the pressure to make the red light go on.
Bill

Good point. I guess I was thinking (1) the H2O sensor would see the water, and (2) the green light is most useful to me in the 30 minutes or so prior to submerging....a good check that I don't have a dirty (or missing!) o-ring.