Thanks; I forgot to mention that.

"Doug Dotson" wrote in message
...
These voltages are for liquid lead-acid batteries. Gels and AGMs
are somewhat lower. My AGMs rest at 12.6v when fully charged.

Doug
s/v Callista

"Garland Gray II" wrote in message
news:IFEQb.11797$dd6.309@lakeread02...
A battery test in an old Ample Power catalog was to charge to 14.4 volts
and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few
hours.

I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few hours.

I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few hours.

Not sure what you are saying here?

Doug

"Brian Whatcott" wrote in message
...

I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts
and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few hours.

Not sure what you are saying here?

Doug

"Brian Whatcott" wrote in message
...

I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts
and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few hours.

For some reason, I had it that a charged battery rested at 12
volts....

Brian W

On Sun, 25 Jan 2004 21:17:45 GMT, Brian Whatcott
wrote:


I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few hours.

For some reason, I had it that a charged battery rested at 12
volts....

Brian W

On Sun, 25 Jan 2004 21:17:45 GMT, Brian Whatcott
wrote:


I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few hours.

Not if it is a good battery. Should rest at 12.8v.

Doug

"Brian Whatcott" wrote in message
...
For some reason, I had it that a charged battery rested at 12
volts....

Brian W

On Sun, 25 Jan 2004 21:17:45 GMT, Brian Whatcott
wrote:


I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts
and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few
hours.

Not if it is a good battery. Should rest at 12.8v.

Doug

"Brian Whatcott" wrote in message
...
For some reason, I had it that a charged battery rested at 12
volts....

Brian W

On Sun, 25 Jan 2004 21:17:45 GMT, Brian Whatcott
wrote:


I found this note from Garland interesting.

I know that, not too long ago, I charged a suspect
battery to 14V+ and checking soon after at 12 volts
expected it to be good.
But it was whacked, and I discarded it.

So I am realising, I did not expect the charging volts to
be reflected in an overvolt reading a day later.
But I will, in future!

Brian Whatcott

On Sat, 24 Jan 2004 20:07:55 -0500, "Garland Gray II"
wrote:

A battery test in an old Ample Power catalog was to charge to 14.4 volts
and
hold it there for an hour. Let it rest overnight, and then retest.
12.8 v & higher=good
12.6 to 12.7v=marginal
12.4 to 12.6v=very poor
less than 12.4 v=worthless

"Rick & Linda Bernard" wrote in message
...
Anyone have a good way of testing 12V deep cycle batteries?

What I was figuring on doing was using a 50watt 12V lightbulb and
measuring
voltage with time. The only problem is that this may take a few
hours.

Doug,

Thanks, very helpful.

So, does this seem valid to you? - An accurate voltage reading is a good
indicator of a battery's condition, but specific gravity is better, and a
slow load test (to 50%) is the best? Or are they testing different things,
all of which are important? Could it do well on a load test without good
voltage or sg's?

And, what use is a commercial load tester, then? Why do they make them? Is
it better than an sg but not as good as a slow load test?

Thanks again. Charles

P.S. I corrected the spelling of "betteries" - couldn't take it any more!

====

Charles T. Low
- remove "UN"
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

====

"Doug Dotson" wrote in message
...
The discharge time of a deep cycle battery is influenced by many
things other than SG. The condition of the plates etc all come into
play. While one may be able to draw heavy current for a brief
period that does not necessarily translate into good low power
performance. A long term low current test tells the actual story
since it is how the battery is being used in normal use. The SG
gives the state of charge from a theoretical sense as does the voltage.