Interesting info on the AGM batteries. I would like to try
those one day.
The only problem we have seen with gel cells is with high
current draw. For a battery to work, the electrolyte needs to “circulate” inside
the cells to come in contact with the plates. With a battery that uses gelled
electrolyte, the circulation or transfer can’t happen as fast, so when there is
high current draw, you can have droops in your power.
It would be cool to find large capacity inexpensive lithium
batteries……
Ron
From:
owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]
On Behalf Of djackson99@aol.com
Sent: Wednesday, August 08, 2007 12:37 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt
Lawnmower Battery
Uncompensated:
"Doc" the creator of the Bionic Dolphin has sold me on Optima AGM batteries. He has had them
down to 150 feet, completely exposed to the pressure. He only sealed the
terminals with "E6000" urethane sealant available at Ace Hardware.
Doc retired one of these batteries after 9 years of service.
Compensated: (From ROV group):
"Pressure test a Gel cell to 3000 ft - Done actually went to 12,500 ft
Our backup battery when we filmed Ghosts of the Abyss was a gel cell
battery with Power Sonic. We made a container with a bladder that was
filled with mineral oil.. Heavier than lithium polymer but safer and
cheaper. -AD Adrian DeGroot"
--Doug J
Tulsa, OK
-----Original Message-----
From: Emile van Essen <emile@airesearch.nl>
To: personal_submersibles@psubs.org
Sent: Wed, 8 Aug 2007 1:53 pm
Subject: RE: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower
Battery
Some of my battery experience :
-The sgt. Peppers (outside) lead /acid battery and thrusters are
pressure compensated by a scuba regulator. Works fine but sometimes little
water enters the system.
Never felt an explosion in salt (brak) waters
-Because the thrusters and battery’s are interconnected, hydrogen
can enter the thrusters. Despite ventilation , once a thrusters did “whoem”
when started.
-once we forget to seal the tow loose connectors from the battery’s
to the hull: the 6 mm contact corroded trough in 30 minutes! Yes the hull
should be not connected to the negative pole to prevent excessive corrosion.
-A 14 AH motorbike battery failed .The battery was overloaded when
it had to crank a 160 ampere turbine starter. It blowed out large quantity of
corrosive steam. I don’t like to happen this at 100 meters with a 200AH
battery………… Another reason to have scuba gear onboard
-I regard closed gel batt. saver for inboard use, but the Nemo crew
encountered a near explosion when the automatic charger fails to swith off.
They had round battery’s!
Ps. Does anybody know til how deep you can use an uncompensated gel
battery? If the air chamber is small enough….
I believe,
I believe. ; )
So why
didn't my battery explode when submerged in saltwater? Did it need more time
submerged then five minutes?
To:
personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower
Battery
Date: Wed, 8 Aug 2007 10:45:12 -0400
From: vbra676539@aol.com
Brent, A battery WILL explode from internal pressure during a direct short to
ground, ie., itself, if submerged in fluid that provides pole to pole xfer!
Drop a wrench across the positive and negative poles (from a distance) if you
don't believe it. I've seen the results. Vance
-----Original Message-----
From: Brent Hartwig <brenthartwig@hotmail.com>
To: personal_submersibles@psubs.org
Sent: Wed, 8 Aug 2007 12:05 am
Subject: RE: [PSUBS-MAILIST] Real Live Submerge Testing on a 12 Volt Lawnmower
Battery
Good Evening Vance,
Thank you
for taking the time to post the below information. True I don't plan to use
lawnmower batteries in my subs. I used that battery for a number of reasons;
it's a 12 volt DC none sealed lead acid battery, basically like most batteries
used in private subs in the past and present, it would be cheap to replace if
damaged in the test, smaller battery = smaller explosion and/or shock, and it's
what I had in hand. I would expect a larger non sealed lead acid battery to
respond in the same basic way. I did the test to learn how to be safe in a
submarine, and so I could design as safe of a sub as I could. For safety, I
filled the bucket remotely from over 50 feet away, and behind a corner of the
house, and the bucket was 30 feet from the house on concrete. When I did the
jumper cable test, the battery was 6 feet away from me on the other side of the
bucket, and I was wearing allot of protective clothing and a full face shield
in case the battery e! xploded and through battery acid at me. When ever I work
on a battery, or use jumper cables, I use protective eye wear at a bare
minimum. I don't know how many times I've done and seen car engine
compartments, including the battery, pressure washed with no apparent ill
affects on the battery, or the person doing the washing nor the dogy in the
window.
Having a
battery explode in a enclosed hardened container, is not the same as it
exploding in an open area. If I put a cup of gun powder on the concrete
and light it remotely, you'll get a big flash and not much else. Now if you put
that same amount of powder in a hard container, like a pipe with threaded end
caps, you now have a whole nother animal. Hydrogen and/or chlorine gas
exploding in a sealed contain because they got lit from a fuse is not the same
as having a battery in the compartment with you, and it getting covered with
water, unless you light the gas(s) some how after they build-up. In that story
the gas exploded from a fuse igniting it, not just the batteries exploding on
there own.
Time will
tell if my mower battery is toasted, but I don't think it would be damaged,
since myself and many others use larger and smaller batteries of all
kinds to produce colloidal silver and hydrogen by way of electrolysis
by using electrodes. Much like I did with the jumper cables. These
batteries get drained over time, but nothing else. We just charge them again
and again. I would highly suspect that having the battery submerged does the
same basic thing, and just slowly drains the battery by producing hydrogen
and oxygen tell spent. It's very true that a higher voltage and
amperage system would produce allot more hydrogen and oxygen faster, of which I
wouldn't want to be around, but that in and of it's self is not an explosion of
the battery(s) until it gets ignited some how by something else besides the
battery. I would think it would take some time to fully discharge the batteries
in that manor. Now h! aving batteries directly connected with wires that can
act as an heating element would be very uncomfortable, if the fuses and/or
ground fault protector(s) didn't work correctly.
Now I
didn't touch the jumper cable ends together underwater while the battery was
submerged, and I didn't open and expose the battery acid to the water. So that
is another matter. That would be testing the battery submerged while under
load, if I touched the cable ends together above or below the water or hooked
them up to a car light or a electric motor. Having the battery by it's self submerged
and producing hydrogen and O2 off the negative post, I would think could
be considered testing while under a light load, depending on the salt
and/or mineral content of the water.
Regards,
"Do or do
not, There is no try"
~ Yoda
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