Re: intro and suggestion on hydrogen venting

[protek@shreve.net]

Vance,
    Good to find another person on here with a working sub.  I also email
Jon Shawl frequently.  I strongly suggest also that anyone with any kind of
lead-acid battery use Hydro Caps.  I use them on my 6 internal batteries.
It is a good investment.  They were slightly less than $6 each when I
bought mine.  That is $18 per battery.  It is as you said, worth it.  There
are a couple of facts that I might bring out about hydrocaps.  First, as
the battery reaches full charge the battery off-gasses more and more
hydrogen.  This full charge state can be monitored by the temperature of
the Hydro Cap itself.  In the first phase of charging they are cool and
then they get warmer as the battery finished the charge cycle.  If a Cap
stops working then it is cooler than than the others on the battery.  Also,
if a battery has a bad cell it can be noted by temperature change either
one way or the other.
    I have thought of using a linear temperature sensor such as the LM35DZ
epoxied to each Hydro Cap to monitor the charging cycle temperature.  If
anyone is interested I can discuss this more, but I think such a system
would be valuable in monitoring each battery cell.  An automatic shut-down
of the charger could be accomplished based on temperature rise.
    Vance, I have a web site if you are interested showing some photos of
my sub at:

http://www.shreve.net/~protek

Gary Boucher



At 07:48 PM 4/14/99 EDT, you wrote:
>Evening all,
>	I'm a new guy to the group with a K-350 and some experience in 
>commercial submersible operations (including a couple of dozen dives in one 
>of Phil N's subs before he bought it).  I have a significant library on 
>submersibles and operations, so if I can be of any help as a resource then 
>feel free to ask--I'll try to answer.
>	Was talking {emailing) Jon Shawl who had responded to some questions 
>of mine, which brought to mind internal batteries.  I have some experience 
>with them, too, as well as first hand knowledge of what happens when someone 
>makes an error in judgement.  Jon charges his batteries with the hatch open 
>and a with a fan blowing.  I would like to remind one and all that AC fans 
>make sparks, too, and if they make them at the wrong time .... well, you 
>know.  Bang!  I would suggest using something like bilge blowers (12 volt
and 
>available from any marine supply catalogue) which can be piped in from 
>outside through flex hose, supplying fresh air to the charging area and 
>forcing enough circulation to get the Hydrogen out the stack (conning
tower). 
> Hydro caps are pricey and can be poisoned if the battery is tipped far 
>enough to wet the catalyst, but are absolutely essential for operational 
>safety.  Maintenance free batts ain't what they are cracked up to be, and 
>vent hydrogen anyway, so plan on the H-caps as part of the expense, bite the 
>bullet, and stay in one piece awhile longer.
>Happy psubbing,
>Vance Bradley
>
>