"Gould 0738" wrote in message
...
If you only test your batteries while a battery charger is runnning, then you
know very little about batteries.

You must have a very clean hog, with all that wash on hand.

Real life scenario for you:

When I go aboard my boat and prepare to get underway, I check the battery
voltmeter on the distribution panel. It always reads just over 13 volts.
Before
I start the engine, I shut off the shorepower to the vessel. When the
shorepower is shut off, the battery charger is not "running".

Does the voltmeter take a nosedive to 12.6? No, it does not. It remains at
over
13.

Why do you care? If it was on the charger overnight it should be fully charged.
Even if the battery is near death it probabaly won't show at that point.


Yes, if I wait long enough the voltage will begin to drop.

But my fully charged batteries show 13.2 volts *without* the charger running.

Are you one
of those bozos that runs a genset all night long?

I don't run a genset at all. Propane galley boat with a diesel furnace. Two
Rolls 8D batteries. Not even equipped with a genset.

Are you one of those bozos who prefers to believe that the state of charge
represented by the .6 volts between 13.2 and 12.6 never existed, simply
because
the first .6 volt bleeds off?

So if you stop and anchor, shut off the engine, relax for an hour or so, then
check the battery and it reads 12.6, do you assume the battery is discharged?
Everyone else would say it virtually fully charged. The bottom line is that the
extra 0.6 Volts is an artifact of a recent charge, not a sign of depletion.