In article <HK1rc.58$1D4.24@newsfe4-gui>,
Burgerman <burgerman (AT) ntlworld (DOT) com> wrote:
Most car charging systems never fully charge the battery either -
regardless of how long the engine is run.

--
He who laughs last, thinks slowest.

Dave Plowman dave.sound (AT) argonet (DOT) co.uk London SW 12
RIP Acorn

"Dave Plowman" <dave.sound (AT) argonet (DOT) co.uk> wrote

Yep... True.
But in general a car battery is used for short bursts, then is topped up say
95 to 98 percent.
This is "enough" to give a pretty long service life @ around 3 years.

In article <Z%2rc.26$Nh3.20@newsfe6-win>,
Burgerman <burgerman (AT) ntlworld (DOT) com> wrote:
But it's not a long life. When I started motoring, a decent battery would
give around 5 years - and this with a crude dynamo, or rather crude
control gear. So despite all the advertising hype, there's not been much
*real* progress in lead acid design for many years - if at all. Perhaps
the relative price has come down, but so has everything like this.

--
*A bartender is just a pharmacist with a limited inventory *

Dave Plowman dave.sound (AT) argonet (DOT) co.uk London SW 12
RIP Acorn

Yes that's indeed the situation, these are AC Delco MF batteries, they
have the 'magic eye' build in hydrometer but that acts on 1 cell only.
Also, all the boiling of the battery for so many hours till the whole
building floor had an extreemly strong foul odor would make me think
that there isn't much electrolyte left in the batteries.

What do you mean 'only finish topping up after charging'? Do you mean
in a normal wet battery with filler cap, you should charge it fully
then top up the battery water? why is this so?

Thanks burgerman.


On Thu, 20 May 2004 14:59:34 +0100, Dave Plowman
<dave.sound (AT) argonet (DOT) co.uk> wrote:

"Dave Plowman" <dave.sound (AT) argonet (DOT) co.uk> wrote

single day even for a few hours as you sleep! For example my van has,
engine management keeping its memory topped up, immobiliser, or car sterio,
or clock, or burglar alarm, fuzy logic gearbox memory, electric seats, and
electric ramp! As well as a radio reciever listening for my key code to
unlock it via central locking and climate control memmory ... And a few
more!

This is the one main thing that shortens life.
Another is "maintainance free" batteries... The other metals (like calcium)
help it to not gas as easily so no topping up. hence maintainance free.
They do NOT help its longevity at all! Just the opposite...

At the moment the best option is pure lead plates, and thin starved glass
mat seperator, soaked in acid (not gel!) The acid can gas if incorrectly
charged but batteries like the Optimas, and Hawker Odyssey range are
"recombinant" and recombine the oxygen/hydrogen back to water, so they do
not dry out... So AGM batteries give the same longevity as an old type high
quality pure lead acid battery, but still maintainance free. Best of both
worlds...
Plus the optimas use MUCH thinner pure lead spiral wound plates like a
Ni-Cad battery. This allows much more plare are which is why an optima can
give MORE cranking amps than a nominally "bigger" ah battery. Even the Deep
Cycle ones can! Most deep cycle batteries cannot sucsessfully start a car
unless it is oversize...

Avoid Gel batteries for starting duties at least - pretty crap, in that high
currents, over charging blows bubbles in the gel, leaving big areas of
battery plate bare! Then they go high resistance of course...

"Brian Su" <happyguy_spam_sux (AT) microsoft (DOT) com> wrote

Because the plates need to be covered at least before you begin charging.
If its pretty flat the level will rise as it charges and gets warmer, so if
you topped up first then now its overfull and acid too dilute.

In article <Mz7rc.119$Aw2.73@newsfe1-win>,
Burgerman <burgerman (AT) ntlworld (DOT) com> wrote:
Oh yes there was. In those days any car parked in the street when dark had
to have a parking light on it. They were 3 watts, so about 250mA - more
than the quiescent load on a battery now.

--
*Why is it that most nudists are people you don't want to see naked?*

Dave Plowman dave.sound (AT) argonet (DOT) co.uk London SW 12
RIP Acorn

Dave Plowman wrote:
It's not the battery at fault - it's the cheap charging kit in the car.

You'll often find batteries last longer in expensive cars (Mercedes and the
like) simply because they have better charging circuits.

Nom wrote:

I think you'll find Dave P will disagree with you there.

Also, SWMBOs Escort is now 7 years old and still on the original
battery. It usually only gets used once a week for about three miles
each way (used to be about one) with the odd 250 mile round trip maybe
once a month.

--
Scott

Where are we going and why am I in this handbasket?

You are correct in that vehicle parastic (key off) loads tend to be
greater that the natural self discharge on a lead-acid battery, but
self discharge is what cause batteries to go flat when in storage.
Depending on the plate chemistry and the temperature, it can be as
much as 30% of the battery's capacity per month. Spiral wound AGM
batteries like Optimas have very low self discharge rates; whereas, a
standard (Sb/Sb) battery has very high rates. Higher temperatures
will accelerate the rate too.

Kindest regards,

BiLL.......

www.batteryfaq.org

On Thu, 20 May 2004 19:22:46 +0100, "Burgerman"
<burgerman (AT) ntlworld (DOT) com> wrote: