Let me clarify my 14.8 situation. I do have a new 90HP Merc outboard and
battery purchased last June and the battery was fully charged when I got
that reading. Does that justify that type of reading and is there anything
I can do without pulling the boat out water?

"Wayne.B" wrote in message
...
On Sun, 23 May 2004 15:56:34 GMT, "Ernie"
wrote:
I shall try again.
My boat's gauge and my garmin 220 fishfinder both read 14.8. Is this too
high and should I be concerned?

========================================

Yes it's too high. Check you're batteries after you've been running
for a while. If there are gas bubbles around the battery plates
and/or low electrolyte levels you should be concerned. 14.8 volts
will cause a great deal of electrolyte loss and plate damage if
applied for an extended period of time. It can also damage other
electrical and electronic devices if they are sensitive to high
voltage. Several years ago I had an issue with failing electric fuel
pumps on my generator. The problem was eventually traced to a
defective voltage regulator which was causing the generator battery to
charge at 14.6 volts. It took 3 fuel pumps and a lot of aggravation
before the problem was fixed.

"Ernie" wrote in message
...
Let me clarify my 14.8 situation. I do have a new 90HP Merc outboard and
battery purchased last June and the battery was fully charged when I got
that reading. Does that justify that type of reading and is there
anything
I can do without pulling the boat out water?



Ernie,

Did you measure 14.8 volts with the engine running or off? If off, for how
long did the battery sit without running the engine?

I suspect you are going to say you measured it with the engine running. If
so, that voltage would not surprise me. To put your fears at rest, call the
dealer or a qualified Merc tech and get an answer from them rather than
listening to us old farts argue about batteries.

Eisboch

On Sun, 23 May 2004 13:54:06 -0400, "Eisboch"
wrote:


"Gould 0738" wrote in message
...

I shall try again.
My boat's gauge and my garmin 220 fishfinder both read 14.8. Is this too
high and should I be concerned?

When does it read 14.8?

When the alternator is running?

Your voltmeter will read at a higher number
than the battery's state of charge when there is current from the
alternator
present.
You won't get a reading that reflects only the battery voltage until you
have
discoed the charger or alternator current.



Now wait a minute there Gould!

First of all - if the poster is talking about an outboard - particularly an
older outboard, and he is talking about voltage when the engine is running,
the 14.8 volts might be very typical. Not ideal, but common with outboard
charging systems. Voltage regulation is often very loosey -goosey on some
outboards.

Not that this has anything to do with charging via a small outboard, but
if we change the topic to a battery charger or regulator with remote
sensing, it could be entirely fine and normal that a fish finder or the
boat's voltmeter reads 14.8. It all depends on where the readings are
taking place (closer in the circuit to the charger or to the battery)
and how much voltage drop there is betweent the charger/regulator and
the battery.

Steve

Are you claiming that if you can ever read 13.2 volts from a battery it must
be
fully charged?
Yes or no answer please.

Must be?
No. You could get a false reading.

But you can get a 13.2 reading from a fully charged battery without it being a
false or artificial reading. That's the combined voltage of all six cells
before the battery self discharges to a lower voltage.

After a battery partially discharges, it will stabilize around 12.6. Partially
discharged is not the same as fully charged- although it will represent a
common state of charge for batteries that have been removed from
a float charer and allowed to self-discharge to that level.

Why do you suppose every battery charger mfg sets float voltage at 13.2 or
13.3?
Just an arbitrary number?

I'm amused to see that the laws of physics are suddenly suspended when they
don't support your tottering argument. :-)

Now wait a minute there Gould!

First of all - if the poster is talking about an outboard - particularly an
older outboard, and he is talking about voltage when the engine is running,
the 14.8 volts might be very typical.

I saw nothing in the OP to indicate inboard, outboard, or otherwise.

Not ideal, but common with outboard
charging systems. Voltage regulation is often very loosey -goosey on some
outboards.



Could you please elaborate on your comment, "Your voltmeter will read at a
higher number than the battery's state of charge when there is current from
the alternator present."

I hope you mean to the limit set by the voltage regulator. If for some
other reason, please explain.

Eisboch

Yes, if the system is functioning properly up to the limit set by the voltage
regulator.
14.8 seems a tad high for the regulator....


but as you say we don't know about many things here.

when the voltage reads 14.8

type of battery....flooded, gel, or AGM

inboard vs outboard

etc.

Yet another irrelevant link. Why do you keep posting links to high school
physics experiments, rather than acknowledging the information from the
leading
manufacturers and experts?

Way back at the beginning of this thread, the argument began when I commented
that a battery consists of 6 cells at 2.2 volts per cell, or 13.2 total volts.

Several geniuses corrected me, stating that the number is only 2.1 volts per
cell, not 2.2. Is the number no longer 2.2, as it has been since the invention
of the battery because a battery company and Nigel Calder say that's the case?

What other laws of physics are vetoed by
claims on a commercial web site? It would be handy to have a list.

The folks who believe that there is no
"actual charge" above 12.6 volts are free to manage their 12-volt systems
accordingly.
Perhaps Nigel Calder or the Trojan Battery guys will come tow them.

"Gould 0738" wrote in message
...
Yet another irrelevant link. Why do you keep posting links to high school
physics experiments, rather than acknowledging the information from the
leading
manufacturers and experts?

Way back at the beginning of this thread, the argument began when I commented
that a battery consists of 6 cells at 2.2 volts per cell, or 13.2 total volts.

Several geniuses corrected me, stating that the number is only 2.1 volts per
cell, not 2.2. Is the number no longer 2.2, as it has been since the invention
of the battery because a battery company and Nigel Calder say that's the case?

What other laws of physics are vetoed by
claims on a commercial web site? It would be handy to have a list.

The folks who believe that there is no
"actual charge" above 12.6 volts are free to manage their 12-volt systems
accordingly.
Perhaps Nigel Calder or the Trojan Battery guys will come tow them.


BWAHAHAHAHA! Now its a conspiracy! Trojan, Rolls, and Calder are ganging up
on poor Gould!

"Gould 0738" wrote in message
...
Are you claiming that if you can ever read 13.2 volts from a battery it must
be
fully charged?
Yes or no answer please.

Must be?
No. You could get a false reading.

Exactly. You have no information. The battery could be at 60% or it might be
at 100%. You have to wait until the voltage stabilizes.



But you can get a 13.2 reading from a fully charged battery without it being a
false or artificial reading. That's the combined voltage of all six cells
before the battery self discharges to a lower voltage.

It isn't "self discharge."


After a battery partially discharges, it will stabilize around 12.6.
Partially
discharged is not the same as fully charged- although it will represent a
common state of charge for batteries that have been removed from
a float charer and allowed to self-discharge to that level.

Since this happens fairly quickly, are you now claiming that battery will loose
a sustantial part of its charge in the the first 10 minutes? It was at 100%
then it drops to what, 80% ten minutes later? Then magically it goes into a
mode where it only looses 5% a week? What color is the sky in your world?



Why do you suppose every battery charger mfg sets float voltage at 13.2 or
13.3?
Just an arbitrary number?

What does this have to do with anything?



I'm amused to see that the laws of physics are suddenly suspended when they
don't support your tottering argument. :-)

Tottering? You just admitted I was was right! Your words: "You could get a
false reading." You originally claimed that 13.2 meant the battery was fully
charged. Now you admit it could be a false reading. Your right. The only way
to tell what the true state of charge is to wait for the voltage to stabilise
(not self-discharge). If it stabilises at 12.6, its fully charged.

"Eisboch" wrote in message
.. .

"Ernie" wrote in message
...
Let me clarify my 14.8 situation. I do have a new 90HP Merc outboard
and
battery purchased last June and the battery was fully charged when I got
that reading. Does that justify that type of reading and is there
anything
I can do without pulling the boat out water?



Ernie,

Did you measure 14.8 volts with the engine running or off? If off, for
how
long did the battery sit without running the engine?

I suspect you are going to say you measured it with the engine running.
If
so, that voltage would not surprise me. To put your fears at rest, call
the
dealer or a qualified Merc tech and get an answer from them rather than
listening to us old farts argue about batteries.

Eisboch

You are right. The engine was running. As you suggested, I will call my
qualified Merc tech tomorrow morning to get the right stuff though I suspect
you might be right. Thanks for the information.

On 24 May 2004 00:15:23 GMT, (Gould 0738) wrote:

Are you claiming that if you can ever read 13.2 volts from a battery it must
be
fully charged?
Yes or no answer please.

Must be?
No. You could get a false reading.

But you can get a 13.2 reading from a fully charged battery without it being a
false or artificial reading. That's the combined voltage of all six cells
before the battery self discharges to a lower voltage.

After a battery partially discharges, it will stabilize around 12.6. Partially
discharged is not the same as fully charged- although it will represent a
common state of charge for batteries that have been removed from
a float charer and allowed to self-discharge to that level.

Why do you suppose every battery charger mfg sets float voltage at 13.2 or
13.3?
Just an arbitrary number?

I'm amused to see that the laws of physics are suddenly suspended when they
don't support your tottering argument. :-)

If you want to talk laws of physics, you're all wrong. Sure, you can
find web sites that support just about any voltage of a lead acid cell
from about 2 volts to 2.2 volts with most of them supporting a claim of
around 2.1 to 2.15 volts. But if you want to talk physics, why not
write out the half-cell reactions that take place at the cathode and
anode of a lead-acid battery. Add them up and that is the potential of
the battery.

I'd write them here but the characters are hard to reproduce in ascii so
I'll just say that the anode reaction is about 0.36v and the cathode
reaction is 1.69v for a total of 2.05v. You can look them up yourself
by googling pbs04 half-cell reactions. Now, to see why 2.05v can really
be anything "around" there due to differences in the concentrations of
the chemicals as well as temperature, google the Nernst equation, which
tells you how the potential of the cell varies according to temperature
and concentration.

The Nernst equation also explains part of why a lead-acid cell will have
a higher voltage when it's just taken off a charger and then settle to a
full-charge voltage a little bit lower and still be considered to have a
100% charge. It has to do with 1) the concentrations of the chemicals
at the plates equalizing some time after removing the charging voltage
and 2) the cooling down after charging which lowers the potential. It
nothing to do with self discharge or internal resistance.

Steve