"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

Nobody sugggested that fusing isn;t necessary. Just that is does not
necessarily protect against a shorted cell. I had a cell short once
and all it did was lower the voltage of the battery and discharge the
parallel battery. No dramatic event, just dead batteries.


If you had measured the voltage across the internal straps on the "shorted
cell", I doubt you would have found it to be zero, like a shorted cell must
be. You'd have found a "dead cell", one whos acid and lead had been
converted into lead sulphate crystals that can't be charged.

Big difference.

--
Larry

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

Subject: One or 2 groups of Batteries??
From: "Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom
Newsgroups: rec.boats.cruising


"Rosalie B." wrote in message
...


Sorry, Rosalie. He's quite wound up this morning...(C;

--
Larry

"Larry" wrote in message
...
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

Nobody sugggested that fusing isn;t necessary. Just that is does not
necessarily protect against a shorted cell. I had a cell short once
and all it did was lower the voltage of the battery and discharge the
parallel battery. No dramatic event, just dead batteries.


If you had measured the voltage across the internal straps on the "shorted
cell", I doubt you would have found it to be zero, like a shorted cell
must
be. You'd have found a "dead cell", one whos acid and lead had been
converted into lead sulphate crystals that can't be charged.

Big difference.

--
Larry

How would I go about measuring the voltage across the internal straps?

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in
:

How would I go about measuring the voltage across the internal straps?


Put the meter probes down into the cell hole and press them into two
adjacent plate ends. They're flat. You'll be measuring the voltage across
the one cell your holing.

Don't forget to wash off the meter probes in clean water with your hands
after you're done. Submarine batteries are easier...individual cells...but
I wouldn't want to be 150' down when there was a short...6,250AH cells.

The battery shop at the Charleston Naval Shipyard rebuilt diesel sub
batteries when I was a young sailor. They'd take an overhead crane and
pick up the plates out of the rubber case by its big terminals. After it
drained for a while, they'd lay the plates on a regular wooden pallet. A
steel bar, probably 2" in diameter was placed across both terminals to
short the plates. That bar would glow red hot for hours on a cell with NO
ELECTROLYTE, running on the acid left in the separators. I was always
fascinated in that shop and learned a lot about battery maintenance and
repair from the experts that had done it for years. In the charging
theatre, the cells were set in lines with aisles between so each cell could
be constantly monitored and tested. Huge conductors were attached to each
cell from overhead. Standing above it all was the operator's control room,
looking over the babies on the floor. The "charger" was another BUILDING
with huge, open-faced generators powered by the shipyard's steam plant
system. Each cell was "cycled" 3 times to soften the plates before it was
charged for the "load test" it had to pass before being loaded back on
railroad cars back to the subs for replacement. Huge load banks with
monstrous fans carried off the energy discharged from the cells. There was
enough heat coming out of the building to heat all the homes in the city
all winter...just vented outside. Acid was recycled but used to be just
dumped into the river way back. Even small batteries the Navy owned (er,
ah, and some lucky sailors' batteries) could be easily repaired, bad cells
replaced then the whole thing brought up and standarized like new. There
was one under the rear seat of my 1967 Volkswagen Campmobile (Kombi) that
took up the whole compartment. It was a Greyhound bus battery that was
restored at the battery shop by some friends. The poor VW never charged
under 20A. The shop converted it from a diesel starting battery to an
850AH long-life deep cycle. Starting the little 57hp VW engine didn't even
dim the headlights!...(c; I used to camp with it where there was no power,
leaving the drop lights in my campsite on all night, all weekend. Fans,
TV, we had it all...(c;

--
Larry

In article ,
(Mic) wrote:

Do you consider it better to have one or 2 sets of house batteries?

snip

http://www.amplepower.com/primer/prefer/index.html

" The Preferred System

The Preferred System consists of a single house bank, and a dedicated
starter battery for all engines. A separate generator battery is
sometimes present. "

We have two banks for much the same reasons as Rosalie, but for our
moderate needs that are now mostly handled by solar, I'm tending towards
a smallish battery directly connected to the alternator with a
paralleling switch if I need to charge the house.

That would make it impossible to fry the alternator by switching the
wrong way by accident. In addition, I could shorten the primary battery
cables considerably, making it more likely that we'll start under all
conditions. The only downside is if the starting battery dies, but since
it won't usually have any but starting loads, it'll last a longer; I've
had original-equipment car batteries last a dozen years.


--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/