Martin,
I must say that you are really off the mark. The construction of car
batteries has changed considerably as you have stated, but that construction
change has been a real performance booster, not a quality issue. The problem
for automotive application is the effective discharge rate of the plates. It
has been known for many years that the larger the surface area of the plate
is, the higher the discharge current can be without killing the cell. The
issue is that the excess electrons on the plate surface are immediately
available for discharge, but those excess electrons within the interior of
the lead plate must first migrate to the surface in order to be discharged
and that takes time. In the past, thin plates of pure lead would fail when
subjected to vibration, so a lead alloy was used. The alloying material was
antimony and metallic arsenic, which added strength and resistance to
vibration. The down size was the alloys also killed durability and cell
efficiency. The big change occurred with the availability of high
temperature plastics. Today, new batteries are made with a lead filled thin
plastic fabric. This has allowed a much larger cell surface area that is
exposed to the electrolyte along with a large increase in vibration
resistance, overall strength, the use of pure lead increasing efficiency and
all this within a much smaller overall size. This change is also the reason
why hydrogen outgassing during high rates of charge has also been reduced.
That is also why it is no longer necessary to remove the cell caps during
the charge process. We now have a new rating system that advertises this
change in ability. It is called "The cold cranking discharge rate", because
the migration of free electrons from the interior of the plate to the
surface is drastically affected by temperature.
Steve

"Eastburn" wrote in message
...
I think the difference between real heavy plated batteries that would
crank a car or truck for an hour to those of today that are
both gel cell and thin plates.

I had my truck battery replaced - it was a year old after all - and it
was
replaced with a thin plate junker. It often gives trouble if I don't
drive over the weekend or it sits to long or multiple starts without
a long charge run. These so called ENVIO batteries are not up to grade.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder