On or around Tue, 18 Jan 2005 11:49:35 +0000, Mr.Nice.
<markvarleyphoto@*nospam*softhome.net> enlightened us thusly:

>I have a 90Ah leisure battery that went flat whilst stored so I've had
>it on a 4amp charge for about 4 days and the charger still indacates
>it's charging.
>It seems to be taking a long time, is the battery fecked?

measure the voltage, disconnect the charger, measure the voltage, wait an
hour or so, measure the voltage.

about 14V, 13.5V, 12.8V or so, I should think.

if you get 14V, 13V, 10V then it's shagged.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Something there is that doesn't love a wall."
Robert Frost (1874-1963)

On Tue, 18 Jan 2005 16:40:10 +0000, Mr.Nice. wrote:

> charger off - 13.78 volts.
> 30 minutes later - 13.57 volts.

Seems a healthy enough off load voltage. Try bunging a bit of load,
that 15W bulb again (indicator or similar) on it and see what happens.
Small drop OK but more than about a volt isn't so good.

--
Cheers new5pam@howhill.com
Dave. pam is missing e-mail

Mr.Nice. wrote:

> and a couple of hours later down to 13.31. not sure I like the idea of
> it dropping with no load on it. but then I suppose that the rate it's
> dropping would not be a problem as I plan to use it on a split-charge
> to run aux lights, charge torches, camera batteries, laptop etc.

That's the float charge being dissipated. Once it's fully dissipated it
should drop to approx 12.6v when fully charged - the quickest way to
remove the float charge is to draw about 10 amps out for a couple of
minutes then leave the battery to stand for half an hour or so before
testing.

After dissipating the float charge at 20 degrees C fully charged will be
about 12.62v, half charged about 12.0v and dead flat about 11.62v.

HTH

--
EMB

On or around Wed, 19 Jan 2005 08:34:24 +1300, EMB <embtwo@gmail.com>
enlightened us thusly:

>Mr.Nice. wrote:
>
>> and a couple of hours later down to 13.31. not sure I like the idea of
>> it dropping with no load on it. but then I suppose that the rate it's
>> dropping would not be a problem as I plan to use it on a split-charge
>> to run aux lights, charge torches, camera batteries, laptop etc.
>
>That's the float charge being dissipated. Once it's fully dissipated it
>should drop to approx 12.6v when fully charged - the quickest way to
>remove the float charge is to draw about 10 amps out for a couple of
>minutes then leave the battery to stand for half an hour or so before
>testing.
>
>After dissipating the float charge at 20 degrees C fully charged will be
>about 12.62v, half charged about 12.0v and dead flat about 11.62v.

mind, the heavy-discharge tests for the rated starting current run the thing
down to about 1.2 or 1.4 V per cell, for a total voltage about 8V...

but yeah, anything substantially below 12V after it's been sitting for a few
hours is not good.

The one under discussion sounds OK, though. Of course, the electrolyte
level's been checked... ?

I once got a free battery that way. Someone had dumped it in a car park - I
found it, looked at it and noted only about an inch of electrolyte in each
cell. Took it home, filled it up with distilled water, charged it, and it
ran the car for about a year and was still on the car when I sold it.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Chuck didn’t reply, so George swung round in his saddle. He could just
see Chuck’s face, a white oval turned toward the sky.
'Look,' whispered Chuck, and George lifted his eyes to heaven.
(There is always a last time for everything.)
Overhead, without any fuss, the stars were going out"
Arthur C. Clarke, "The 9 billion names of God"

Mr.Nice. wrote:

> On Tue, 18 Jan 2005 22:52:48 +0000, Austin Shackles
> <austin@ddol-las.fsnet.co.uk> wrote:
>
>>On or around Wed, 19 Jan 2005 08:34:24 +1300, EMB <embtwo@gmail.com>
>>enlightened us thusly:
>>
>>>Mr.Nice. wrote:
>>>
>>>> and a couple of hours later down to 13.31. not sure I like the idea of
>>>> it dropping with no load on it. but then I suppose that the rate it's
>>>> dropping would not be a problem as I plan to use it on a split-charge
>>>> to run aux lights, charge torches, camera batteries, laptop etc.
>>>
>>>That's the float charge being dissipated. Once it's fully dissipated it
>>>should drop to approx 12.6v when fully charged - the quickest way to
>>>remove the float charge is to draw about 10 amps out for a couple of
>>>minutes then leave the battery to stand for half an hour or so before
>>>testing.
>>>
>>>After dissipating the float charge at 20 degrees C fully charged will be
>>>about 12.62v, half charged about 12.0v and dead flat about 11.62v.
>>
>>mind, the heavy-discharge tests for the rated starting current run the
>>thing down to about 1.2 or 1.4 V per cell, for a total voltage about 8V...
>>
>>but yeah, anything substantially below 12V after it's been sitting for a
>>few hours is not good.
>>
>>The one under discussion sounds OK, though. Of course, the electrolyte
>>level's been checked... ?
>>
>>I once got a free battery that way. Someone had dumped it in a car park -
>>I found it, looked at it and noted only about an inch of electrolyte in
>>each
>>cell. Took it home, filled it up with distilled water, charged it, and it
>>ran the car for about a year and was still on the car when I sold it.
>
>
> Yep the electrolite is all fine, I'll bring a bulb along tonight and
> try it with a bit of load. If it looks OK I'll put it on an 8amp
> charge and see how it goes.
>
>
> Regards.
> Mark.(AKA, Mr.Nice.)

One thing you should recognise is that the rated charge of the charger is
not likely to be what it is actually charging at - so it is probably not
had as much charge as you think it has. Most chargers drop the current well
below the rated charge as the voltage rises. For example, I have at present
an 8amp charger on a 760AH battery - at 13.6 volts, the charger is only
delivering about 1.8Amps. On a fully charged, good, battery the voltage
will be around 14v at full charge while charging at 5-10% of rated
capacity, but with the charging stopped will drop to 13.2 volts with no
current draw. What it drops to under load will depend on the load, but
again, with around 5-10% of the rated capacity load, it should remain
around 12-12.5V and drop only slowly until about half discharged.
JD

On or around Wed, 19 Jan 2005 20:18:25 +1100, JD <jjd@SPAMLESS.com.au>
enlightened us thusly:

>760AH battery

wot's it for, a submarine?

I think you're confusing AH with cranking current.

760 Ah would let you draw 760 amps for an hour, which is a pretty damned big
battery!

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
In Touch: Get in touch with yourself by touching yourself.
If somebody is watching, stop touching yourself.
from the Little Book of Complete B***ocks by Alistair Beaton.

Austin Shackles wrote:

> On or around Wed, 19 Jan 2005 20:18:25 +1100, JD <jjd@SPAMLESS.com.au>
> enlightened us thusly:
>
>>760AH battery
>
> wot's it for, a submarine?
>
> I think you're confusing AH with cranking current.
>
> 760 Ah would let you draw 760 amps for an hour, which is a pretty damned
> big battery!
>
Main house power supply. My house is supplied by two 24v 760AH and one 12v
400AH battery banks charged by twenty solar panels and running three
inverters. I got a number of second hand spare cells, and the set referred
to is getting a maintaining charge.

I assure you I know the difference between cranking amps and AH. The cells
in question would not have a "cranking" current more than about 150A, as
they are, of course, deep cycle cells.
JD

On or around Thu, 20 Jan 2005 06:54:48 +1100, JD <jjd@SPAMLESS.com.au>
enlightened us thusly:

>Austin Shackles wrote:
>
>> On or around Wed, 19 Jan 2005 20:18:25 +1100, JD <jjd@SPAMLESS.com.au>
>> enlightened us thusly:
>>
>>>760AH battery
>>
>> wot's it for, a submarine?
>>
>> I think you're confusing AH with cranking current.
>>
>> 760 Ah would let you draw 760 amps for an hour, which is a pretty damned
>> big battery!
>>
>Main house power supply. My house is supplied by two 24v 760AH and one 12v
>400AH battery banks charged by twenty solar panels and running three
>inverters. I got a number of second hand spare cells, and the set referred
>to is getting a maintaining charge.
>
>I assure you I know the difference between cranking amps and AH. The cells
>in question would not have a "cranking" current more than about 150A, as
>they are, of course, deep cycle cells.
>JD

fair enough. I sit corrected. Bet you could run a submarine on 'em, an'
all.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Remember that to change your mind and follow him who sets you right
is to be none the less free than you were before."
Marcus Aurelius Antoninus (121-180), from Meditations, VIII.16