Because they’re in pressure housings, remaining at 1 atmosphere.
Waterproof Key Bag for Diving
- Thread starter Marlene996
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OP
Just to play devils advocate; If your air compression at 40m is 1/5th, there is still air.
So if you have some air in your bag when you start your descent, there is still 1/5th of the air in the bag at 40m. Essentially, there is nothing directly pressing on the button. There is also equal pressure from the inside of the key fob pushing in the opposite direction as the key fob is not a sealed device with air inside pulling the button toward it. The air inside of the bag and the air inside of the keyfob are both inside of the bag moving freely under "equal pressure".
That's exactly why we use solid housings to protect cameras when diving. GoPros are supposed to be "waterproof" but if you read their specs, that is only to 10m. If you go deeper you need a housing.
GoPros are small, have only 2 controls that need to be built into the housing and the market is huge, so you can buy a housing for as little as $20. Some people actually use these to carry their keys and other valuables on dives. Housings for full size cameras with multiple controls that are rated for tech diving depths can cost thousands.
They are in hard cases.
If you have a flexible pouch it will get squeezed by the pressure, so the pressure inside will change as well.
In a dry suit you add air to keep the volume constant, but it of course results in more pressure.
A gopro housing is solid, so (nearly) no volume change and thus internal pressure basically the same.
So a lot of people carry their electronic car key inside a dry suit. Most have no issues, some report of empty batteries or other effects as buttons have triggered. As your pouch will squeeze I guess the risk is higher that a button is pressed.
Batteries have a theoretical risk, but I guess as a lot of people do it, its not too big.
In a dry suit you add air to keep the volume constant, but it of course results in more pressure.
A gopro housing is solid, so (nearly) no volume change and thus internal pressure basically the same.
So a lot of people carry their electronic car key inside a dry suit. Most have no issues, some report of empty batteries or other effects as buttons have triggered. As your pouch will squeeze I guess the risk is higher that a button is pressed.
Batteries have a theoretical risk, but I guess as a lot of people do it, its not too big.
OP
I have several housings myself. I understood the need for it was due to seal failures on cameras/phones/go pros at x-depth. GoPro is now to 15m. iPhone 15/16 is 6m 30 minutes, but 30 minutes is a test standard and likely will withstand much longer exposure at this depth.
A short search reveals several research articles on pressure and li-ion batteries showing that physical pressure increases the lifespan of the battery. Here is one: https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/batt.202200452
There is information on general pressure on Li-Ion also in relationship to flying and altitude which is destructive to the battery, but not a lot of information of depth pressure on li-ion batteries. I imagine as the device that uses them needs a housing it hasn't been necessary to investigate really for this purpose we are discussing now.
That's not how pressure works. It exerts a force on everything exposed to it which is every square mm of the surface of your bag. That pressure will get transmitted to every surface inside the bag.
I'm going into trivia mode. Feel free to stop reading now.
The only ways to counteract this are to have solid cases that resist the pressure (like a submarine or camera housing) or a flexible case where you have the ability to add enough gas to the inside to equalize the pressure as you descend (and to vent as you ascend).
The latter is how scuba dry suits work. There is a line plumbed into the suit from a regulator to a valve that allows the diver to add air to the suit to equalize pressure. If you are diving a dry suit and descend you can feel the pressure squeezing you until you add air. There have been deaths where divers couldn't add air for some reason and the pressure became so high they couldn't move their limbs to address the problem
Hey Marlene, we had tried a few of the existing flexible pouch solutions in the past and they tended to dry and crack. Your idea of using life vest material sounds like a good idea to overcome that. We also had problems with a variety of the plastic canisters leaking. Keebunga was pretty big with surfers as a solution and had a solid following, not sure if that is still the case, but I did see they also seem to be testing the solution to some depth.
Disclaimer: We ended up making our own solution out of solid aluminum (that we also sell) but we realize this may not be the answer for everyone. We wish you luck with your product and with your business. The more solutions and options that are out there for divers the better! Scuba board is also a great forum for input and feedback as you've probably already seen
Disclaimer: We ended up making our own solution out of solid aluminum (that we also sell) but we realize this may not be the answer for everyone. We wish you luck with your product and with your business. The more solutions and options that are out there for divers the better! Scuba board is also a great forum for input and feedback as you've probably already seen
Uhhhh, your marketing is pretty good, but your physics sucks. And the issue is not really pressure on the battery itself, but rather pressure on the buttons, that turns on and drains the battery, and thus might make it hot if it stays on for a long time. Hot Li-Ion batteries are not good.
OP
Hi Jaan, Your product looks like much better quality than the plastic ones! Probably the most ideal solution pressure-wise. Keebunga I had never heard of but it looks limited in shape. I don't think it would fit my monster Jeep fob and I can't detach the manual key.Hey Marlene, we had tried a few of the existing flexible pouch solutions in the past and they tended to dry and crack. Your idea of using life vest material sounds like a good idea to overcome that. We also had problems with a variety of the plastic canisters leaking. Keebunga was pretty big with surfers as a solution and had a solid following, not sure if that is still the case, but I did see they also seem to be testing the solution to some depth.
Disclaimer: We ended up making our own solution out of solid aluminum (that we also sell) but we realize this may not be the answer for everyone. We wish you luck with your product and with your business. The more solutions and options that are out there for divers the better! Scuba board is also a great forum for input and feedback as you've probably already seen
I just did a simple pressure check on the fobs from two different cars. One engages at 600g pressure, the other at 1400g pressure so there is also quite a bit of variety in how much pressure causes it to engage.
If what @tursiops suggests is true, then putting a hard cover over the key buttons wouldn't help as the general pressure would cause the buttons to compress. But again if there is air inside the bag and the air is exerting equal pressure on both sides of the button then the button would not engage as long as nothing externally pushed on it.
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