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Re: [PSUBS-MAILIST] Lead-Acid Oil-Filled Batteries and Catalysts



Hi Doug.
 
Oh yes Doug, I will be able to do that in my wetsub battery pod also.
 
I too will be able to flow air into my battery pod and exhaust it out also to carry off some of the hydrogen gas and to preclude any vacuum from forming in the battery pod while using hydrocaps also.
 
My original plan was to use a scuba regulator to do this, but I am awaiting Phil Nuytten's advice of what better and beefier valves would replace my scuba regulator system that he doesn't think will be safe enough.
 
But whether I did it with my original scuba regulator plan or with Phil's beefier valves, the principle is the same.
 
Air from my tank will flow into my battery pod (attached under the wetsub) when the water pressure exceeds the air pressure in the battery pod. Then when the pod is equalized with the outside water pressure the air flow will stop. Now upon accending the air in
 
the pod will expand and flow out an overpressure exhaust valve helping to get rid of some of the hydrogen just like you said. But even if I did not want to accend, I could manually vent air into the battery pod and the overpressure exhaust valve would just let it
 
bubble out of the pod when the pod was equalized with the outside water pressure and that means I could purge my battery pod of hydrogen whenever I wanted. Any excess air I shoot into it when it is equalized with the outside water pressure will
 
simply come out the overpressure exhaust valve. The weight of my battery pod will act as a keel to keep me from turning over since the battery pod will be slung under the wetsub.
 
If necessary I will add weight to the battery pod to make it somewhat negatively buoyant if necessary. Even though I vent air into the pod to equalize it against the outside water
 
pressure it shouldn't turn over so I wouldn't need the battery pod over my head for the sub to be stable. With the air equalization system I mentioned above, I should be able to vent air into my battery pod any time I choose and purge hydrogen whenever I want to
 
and it will also automatically do it whenever the pod needs to equalize against the outside water pressure. So no need to convert to a dry ambient.  I'd like to build a half dry sub one day. Perhaps a modified Kent Markham Silent runner 2 with a rudder added
 
because Kent told me he had a hard time overcoming the inertia of his forward speed to turn using the thrusters built into the dive planes, even when he reversed polarity on one. But I like his cockpit system and the variable buoyancy tube system.
 
But gotta finish this one first.
 
Kindest Regards,
Bill Akins.
 
 
 
 
----- Original Message -----
Sent: Thursday, February 03, 2005 11:57 PM
Subject: Re: [PSUBS-MAILIST] Lead-Acid Oil-Filled Batteries and Catalysts

Hi Bill
 
The idea about the thermal expansion of oil is just an attempt to explain why there may sometimes be a vacuum on a sealed rigid container with oil in it.  I think Vance mentioned that the oil filled battery pods sometimes had a vacuum on resurfacing. 
 
I've been following your discussion.  I thought the suggestion about a compressible tube attached to the oil filled container was a good one.  I plan to use that to compensate the pressure inside of a winch on my boat.
 
I too think the oil will be messy, but the winch needs lubricant anyway.  Everything else I plan to compensate with air, and that currently includes my battery box.  My ambient dry sub, like the Sport Sub's will free flow about 3 cfm into the cabin, but unlike the Sport Sub I am going to route the exhaust from the cabin onto the other compensated areas.  My batteries will be gel-cell which I think produce less gas.  Someone please correct me here if I am wrong. Anyway, I plan to flow the air into one end of the battery box, and out the other, which will help carry off some of the gas.  I can't think of any way that could be done in a wet sub.  I know you don't want to put the batteries over your head, or flow the air through the battery box first. :)    You sure you don't want to convert to dry ambient?
 
Thanks for all your good discussions
Doug J