Re: Fw: [PSUBS-MAILIST] Re: battery pack

[Doc <doc@bionicdolphin.com>]

Hi Herve,

They were ambient.

Herve wrote:

> > Hi doc,
> > your batteries were in a 1 atm environment or in a ambient pressure
> housing?
> > Herve
> > ----- Original Message -----
> > From: "Doc" <doc@bionicdolphin.com>
> > To: <personal_submersibles@psubs.org>
> > Sent: Wednesday, June 19, 2002 7:09 PM
> > Subject: Re: [PSUBS-MAILIST] Re: battery pack
> >
> >
> > > Aloha Pat,
> > >
> > >  I've been using the Optima batteries for years and have had them down
> to
> > 150'
> > > without a pressurized housing with no problems at all. As a matter of
> fact
> > my
> > > Optima's are 7 years old and still going strong!
> > > In my humble opinion, they're well worth the extra price.
> > >
> > > Doc
> > >
> > > Captain Nemo wrote:
> > >
> > > > Hi Herve,
> > > >
> > > > Interesting point; one not often discussed.
> > > >
> > > > I don't oil compensate my batteries in the NAUTILUS; they are carried
> > > > internally.  We didn't recharge during use, and flat-out ignored the
> > > > possible problem of Hydrogen generation during the proving tests when
> we
> > > > were running Sears Die Hard car batteries back in the Flintstones
> days.
> > It
> > > > did get a little freaky one time when the hatch leaked and brackish
> > water
> > > > came close to the batteries; I was really worrying about chlorine gas
> > that
> > > > time.  They didn't get wet; we lucked out, and we lived and learned.
> > > >
> > > > Now I'm running the sealed OPTIMA batteries; AGM type, in a
> > splash-resistant
> > > > box.  The batteries work at any angle or attitude, and have a vent
> plug
> > on
> > > > the case. The manufacturer says it won't leak any gas at all during
> > normal
> > > > operations or charging.  It's there as a safety valve if one
> > overcharges;
> > > > then it will burp.  Otherwise, you should be able to sleep with the
> > thing in
> > > > your bed without any more problems than complaints from the wife.
> ;-)
> > > >
> > > > They say the structure of the OPTIMA is such that you could shoot a
> hole
> > > > through one cell and still keep running; virtually no leakage due to
> the
> > > > "jelly roll" cell design.  Of course, I haven't taken my batteries to
> > the
> > > > range lately...
> > > >
> > > > But your point about crush depth is well taken.  I'm not really sure
> > exactly
> > > > what kind of voids may exist inside the case; but if there's any at
> all,
> > > > we've got a potential implosion problem at some point way down there.
> > (Not
> > > > with mine, since they're still inside the hull; but if they were
> mounted
> > out
> > > > in the water, yeah.)
> > > >
> > > > But with what I've seen of the diagrams; and by visually inspecting
> the
> > > > outside of an actual battery, (this is an opinion based on a little
> > > > experience taking camera cases and such down underwater) I'd bet these
> > > > things would easily withstand recreational SCUBA depths without caving
> > in,
> > > > and probably a lot more.  Seal the vent with RTV (remove when
> charging)
> > and
> > > > I'd say they were probably suitable for external use on a submarine at
> > > > homebuilt-sensible depths.
> > > >
> > > > They're kind of expensive, so I don't really want to use one for an
> > anchor
> > > > to see if it pops, but one of these days I might just do that.  (Oh, I
> > can
> > > > hear the environmentalists screaming now!)
> > > >
> > > > Since these things are sealed, pressure compensation could be
> difficult.
> > > > Solutions?  Carry them inside and don't charge during use.  Carry them
> > > > inside in a vented box that can be pressure purged overboard.  Carry
> > them
> > > > outside in a pressure pod of their own?
> > > >
> > > > But you've got me wondering.  If I get the time (not today) I'll
> noodle
> > this
> > > > one around a bit with the manufacturer, and see what they think.
> > > >
> > > > Pat
> > > >
> > > > ----- Original Message -----
> > > > From: "Herve" <caribsub@coqui.net>
> > > > To: <personal_submersibles@psubs.org>
> > > > Sent: Wednesday, June 19, 2002 11:27 AM
> > > > Subject: [PSUBS-MAILIST] Re: battery pack
> > > >
> > > > > Pat,
> > > > > 4 x 6 = 24 x 6 Volt golf cart batteries, GC15 lead acid with H20
> > > > > recombination catalytors for free maintenance and no water refills.
> > Being
> > > > > vented they can be pressure compensated
> > > > > with oil in battery you still have to refill them with water on a
> > regular
> > > > > basis.
> > > > > Someone corrects me if i am wrong......
> > > > > mostly during recharge and a little bit on load, a battery releases
> H2
> > and
> > > > > 02 because of the water decomposition in the acid, oil makes the
> > battery
> > > > > compressible when diving true but does not prevent the loss of
> water.
> > > > > "Sealed" Gel batteries or AGM batteries, are not exactly completly
> > sealed,
> > > > > and are not compressible either because of void spaces inside, they
> > are
> > > > > vented out, but not vented in so they would crush under pressure.
> > > > > I used to pressure compensate my gel batteries before so they would
> > not
> > > > > crush at depth, but it is too much work to do that.
> > > > > Herve
> > > > > ----- Original Message -----
> > > > > From: "Captain Nemo" <vulcania@hawaii.rr.com>
> > > > > To: <personal_submersibles@psubs.org>
> > > > > Sent: Wednesday, June 19, 2002 4:43 PM
> > > > > Subject: Re: [PSUBS-MAILIST] external Motors for depths of 1000ft
> > > > >
> > > > >
> > > > > > Herve,
> > > > > >
> > > > > > What's your battery pack consist of?
> > > > > >
> > > > > > Pat
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: "Herve" <caribsub@coqui.net>
> > > > > > To: <personal_submersibles@psubs.org>
> > > > > > Sent: Wednesday, June 19, 2002 10:04 AM
> > > > > > Subject: Re: [PSUBS-MAILIST] external Motors for depths of 1000ft
> > > > > >
> > > > > >
> > > > > > > i attache 4 motorguide 107 lbs on my subs, pretty powerfull, i
> > usually
> > > > > run
> > > > > > > them at 70 %
> > > > > > > They are pressure comp, for no deeper than 140 Ft you dont need
> to
> > > > fill
> > > > > > them
> > > > > > > up with oil.
> > > > > > > Herve
> > > > > > > ----- Original Message -----
> > > > > > > From: "Rob Innes" <innespace@jett.net>
> > > > > > > To: <personal_submersibles@psubs.org>
> > > > > > > Sent: Wednesday, June 19, 2002 4:03 PM
> > > > > > > Subject: Re: [PSUBS-MAILIST] external Motors for depths of
> 1000ft
> > > > > > >
> > > > > > >
> > > > > > > > Does anyone know how much resistance is caused on the trolling
> > > > motors
> > > > > by
> > > > > > > > filling them with the oil? Approximately how much thrust could
> > > > expect
> > > > > > to
> > > > > > > be
> > > > > > > > lost on a Motorguide 107lb thrust unit? Has anyone fitted one
> or
> > > > more
> > > > > of
> > > > > > > these
> > > > > > > > motors to a sub or DPV?  I'd be very interested in the results
> > > > > > > >
> > > > > > > > Rob Innes
> > > > > > > >
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