Batteries are tough

I am trying to make a wearable based on arduino, however it is designed to be submersible. We are going to be encapsulating the entire device in waterproof material and recharging using wireless induction. However I know that batteries give off gas sometimes. Obviously some batteries do not give off gas, like the batteries in medical devices. We talked to medical device battery manufactures but those are WAY expensive($300/unit+). Does anyone have any suggestions on how to overcome the gassing issue or know where I could find a battery to suit my purpose?

I think batteries only outgas when they are overcharged. Make your charging circuit smart enough not to let that happen.

You could use an IP67 or IP68 enclosure that you could open up for charging. Or you could design a sealed enclosure to accept outgassing.

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Are there additional concerns in terms of using magnetic resonance for charging. Thanks for the responses so far. especially to Crossroads who is always answering my post and helping me immensely!!!!!!!

Are there additional concerns in terms of using magnetic resonance for charging.

What does that mean ? You stated that you were going to be using magnetic induction charging as if it were a fact. Are you now asking how to do that ? (I hope not)

recharging using wireless induction.

and

magnetic resonance for charging

Are not the same thing. In fact I am not sure what the latter means.

Magnetic resonance as in Nuclear Magnetic Resonance as in MRI (magnetic resonance imaging, used in hospitals).
I don't know where the OP got the "resonance" term from. I think he just pulled it out of the air.

Yes I was a University Physics lecturer ( professor to those in the U.S. ) so I know what MNR is, but what I don't know is what, "magnetic resonance for charging" is.

Are there additional concerns in terms of using magnetic resonance for charging.

Perhaps you mean induction.
The circuit should be resonant for efficiency.

Oh, Ok , then an LC oscillator on the transmitter that oscillates when XL=XC, or RESONANCE, COUPLED
to the RECIEVER inducing oscillation across the magnetic field gap.

spycatcher2k:
Or LiPO - No Gas under normal charging.

On the other hand, they can explode if they come into contact with water! Just saying...

FYI , Lipo's burst into flames (in your hands) if you puncture the battery with a metalic object, like a pocket knife.

I am using induction, as in this part

Sorry for the confusion.