While picking people's brains about batteries today, I learned why I
haven't
seen a friend of mine around the waterfront in a while. He isn't in
Florida.
He was bending over the battery in his boat a couple months ago when
it blew
up for no apparent cause. In addition to acid burns, the force of the
explosion threw him against the bulkhead of his boat so hard that he
broke
ribs and punctured his lungs. He's been laid up for weeks.

I don't think wet cells have any place on a boat except maybe one that
is
large enough to have a dedicated battery compartment.

--

Roger Long

On Tue, 15 Mar 2005 20:51:49 GMT, "Roger Long" wrote:

While picking people's brains about batteries today, I learned why I
haven't
seen a friend of mine around the waterfront in a while. He isn't in
Florida.
He was bending over the battery in his boat a couple months ago when
it blew
up for no apparent cause. In addition to acid burns, the force of the
explosion threw him against the bulkhead of his boat so hard that he
broke
ribs and punctured his lungs. He's been laid up for weeks.

I don't think wet cells have any place on a boat except maybe one that
is
large enough to have a dedicated battery compartment.


Any further details? I'm just finishing the battery box on
my boat, and maybe there's something I need to know.
Hope your friend recovers soon.
Norm B

After a day of researching batteries, I think the only thing you need
to know is to put AGM batteries in your boat. They will work charging
off standard alternator / voltage regulator combinations, unlike gel
batteries.

More expensive but I think you have to have a really good reason to
carry a gallon or more of liquid sulfuric acid around in your boat.

According to Calder, wet cells have longer life and better performance
but only with a degree of care and feeding that isn't probable on most
boats. The real life mileage of gel's and AGM's is greater because
they are more tolerant of the abusive cycles inherent in most marine
applications.

I just went to give my spare aircraft battery its periodic maintenance
charge. I just moved it to the edge of the shelf in the small room
where I keep it and the phone rang. I realized a half hour later that
my eyes burned and my fingers itched. Just the fumes of a battery
sitting there are corrosive. It boiled over slightly the last time I
charged it and I didn't notice. Two months later, the residue could
make me feel that way. Think of that stuff in your boat.

The only way I could justify wet cells now would be a long distance
cruiser that needs technology available anywhere, can spend a lot of
time maintaining them, and needs maximum performance. If you must go
wet, vent the battery box so the air flow is completely separate from
the interior of the boat.

--

Roger Long



"engsol" wrote in message
...
On Tue, 15 Mar 2005 20:51:49 GMT, "Roger Long"
wrote:

While picking people's brains about batteries today, I learned why I
haven't
seen a friend of mine around the waterfront in a while. He isn't in
Florida.
He was bending over the battery in his boat a couple months ago when
it blew
up for no apparent cause. In addition to acid burns, the force of
the
explosion threw him against the bulkhead of his boat so hard that he
broke
ribs and punctured his lungs. He's been laid up for weeks.

I don't think wet cells have any place on a boat except maybe one
that
is
large enough to have a dedicated battery compartment.


Any further details? I'm just finishing the battery box on
my boat, and maybe there's something I need to know.
Hope your friend recovers soon.
Norm B

"Roger Long" wrote in message
.. .
While picking people's brains about batteries today, I learned why I
haven't
seen a friend of mine around the waterfront in a while. He isn't in
Florida.
He was bending over the battery in his boat a couple months ago when it
blew
up for no apparent cause. In addition to acid burns, the force of the
explosion threw him against the bulkhead of his boat so hard that he broke
ribs and punctured his lungs. He's been laid up for weeks.

I don't think wet cells have any place on a boat except maybe one that is
large enough to have a dedicated battery compartment.

I agree totally. Liquid lead-acid batterys have a bunch of problems. They
are obsolete technology for boat use. Gel or AGM are far better choices.
Even with a dedicated battery compartment Liquid Lead-Acid batteries
are still dangerous.

Doug
s/v Callista

--

Roger Long

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

I agree totally. Liquid lead-acid batterys have a bunch of problems. They
are obsolete technology for boat use. Gel or AGM are far better choices.
Even with a dedicated battery compartment Liquid Lead-Acid batteries
are still dangerous.

Doug
s/v Callista


Drop by a battery shop with the big golf cart batteries. Turn one of 'em
upside down and see what leaks out with the caps on. I dare ya...(c;

The best batteries for a boat are those big, honkin' fork lift batteries,
but most have no place to store that much energy or boat enough to float
that much weight.....

POWER is our friend.

What worries me in a glass mat battery is COOLING. The wetcell battery is
cooled by convective currents in the electrolyte. The flow through the
plate separators vertically keeps a constant flow of cooling water
preventing the plates from warping. How do you cool an AGM battery all
wrapped up in INSULATING FIBERGLASS when that big, honkin' 180A alternator
is trying to satisfy a boater who wants to charge the hell out of it for an
hour to shut down his little diesel, instead of letting it charge SLOWLY so
it can absorb the energy in its relatively slow chemical reaction to
charging current??

Nope...I like liquid-cooled, hard motion (golf cart or fork lift)
batteries...thanks. EVERY big truck comes with them...Ships, too! I
wonder why??

I suspect his friend had either a primary wiring short with no fuse link to
melt, like most boats are wired to the panel, or an internal cell short
out, which is very rare in a modern battery...very rare.

Question - Is he a smoker or could have had something hot near the charging
cells? There's very little gassing, now that we got rid of the antimony
plate supports, unless he was charging the hell out of it fully charged.

In article , says...


I suspect his friend had either a primary wiring short with no fuse link to
melt, like most boats are wired to the panel, or an internal cell short
out, which is very rare in a modern battery...very rare.

I wish I had such luck with the lottery. Internally shorted batteries did
$35,000 worth of damage to my boat. The problem in such a case is not hydrogen
explosion but steam explosion with H2SO4 all over the place.

You make an excellent point that no battery is safe. Anytime you store
up that much power in a small package there is going to be risk when
things go wrong. AGM's certainly can explode if abused.

However, explosions are only part of it. The free liquid acid,
corrosive fumes, and explosive vapors of wet cells are all minimized
with AGM's. If something does go wrong and one blows up, the acid
impregnated mat in the AGM should be less dangerous and easier to
clean up than the liquid.

This is analogous to the gas / diesel propulsion question. If you need
the very best performance and power to weight ration, you have to go
with gas and learn to keep large amounts of explosive fume producing
liquid on board. With care, understanding, and proper equipment, gas
can be made acceptably safe. Diesel is not perfectly safe but it is
much safer and has other advantages such as more moisture tolerant
ignition.

Despite the blanket statement I started this thread with, there are
certainly operational situations in which I might choose wet cells. I
wouldn't expect them in normal yachting situations though.

Speaking of internal shorts, the AGM, with everything held in place
with the glass mat should be far less likely to short than the wet
cell where chunks can fall off the plates and there is only liquid to
keep them from moving around.

--

Roger Long

In article ,
says...

Speaking of internal shorts, the AGM, with everything held in place
with the glass mat should be far less likely to short than the wet
cell where chunks can fall off the plates and there is only liquid to
keep them from moving around.

I would agree. Not just chunks but in an aging and poorly maintained
battery a constgant rain of debris to the bottom of the case where it
eventually shorts out the plates when a heavy load is applied. Our
problem was no-name batteries to begin with which the yard failed to
maintain over a long in-water layup. The following March when moving the
boat I advanced the throttle from slow to WOT and BLAM!

Does ABYC require that AGM batteries have a battery box?

I found the ABYC Standard E-10.6 Storage Batteries - Installation.
Apparently, it does not require a battery box for any type of battery.

Paul
"Paul L" wrote in message
newsNYZd.8872$Z07.4338@trnddc02...
Does ABYC require that AGM batteries have a battery box?