Sealed Lead Acid Batteries - Will they leak under pressure??

[Budgie]

Hi all,
seeking advice from people who have done this before. I am currently trying my hand at building my dive torch (isn't everyone) and was wondering if anyone has had any problems/issues with Sealed Lead Acid batteries when placed under pressure.

I have a 12v, 18amp SLA battery and was toying with the idea of NOT putting it in a watertight, sealed cannister - rather I was wondering how I'd go simply siliconing up the battery terminals to make them watertight (stop rusting/electrolisys etc) and then sit the battery in some sort of protective case/pouch (which ISN'T sealed) and strap that to my tank... I am wondering if having the battery exposed to the water will result in water being forced into the battery due to pressure changes (or gell being forced out of the battery as I get shallower)?? The battery (apparently) is the gel filled type but I don't know how much (if any) air space is inside the battery which will result in pressure buildup the deeper I get... The battery specs are here is anyone is interested:

http://www1.jaycar.com.au/productVi...&pageNumber=&priceMin=&priceMax=&SUBCATID=250

Reason for not wanting to use a proper sealed cannister is simply - trying to save cost/effort and I don't want to make the battery much bigger than it already is (180mm wide x 75mm deep x 170mm high).

All idea's, recommendations appreaciated.

cheers budgie

 

[dilligaf368]

For all the bother trying to get the batteries watertight and keeping the current from the water, why don't you make Your own flashlight ( I guess they call it a "Torch" there).
Just take some PVC pipe with theads on one side and add the wires then seal them. Use Silicone grease to seal the threads. The threads are tapered here so the tighter You turn the fittings the more sealed it becomes.
This way You can reuse the flashlight (torch) over and over again without the expence of a real light.
In the USN I used a flashlight (Yes, a torch) that was made for dry enviroment by inserting the flashlight in a plastic bag and sealing. Depth was a constraint but 100' was OK. Bill