This newsgroup has the greatest selection of experts on the web so I hope
you will excuse me for asking an off topic question about charging lead acid
batteries.

Back in the early 60's when I worked in a service station I was taught to
remove the battery caps when charging a car battery so that's how I taught
my boys to do it. My son just finished his lift truck training course and
they told him to leave the caps on. I checked a number of web sites and
they all say the same thing, leave the caps on.

My question is have I been doing it wrong for the last 50 years or at one
time was removing the caps a standard practice that has since been
considered unnecessay or unsafe?

Thanks in advance

Jimbo

I believe this has to do with venting hydrogen, I think that most modern
batteries have built in vents that can dissipate this, with out the hazard
of having the acid/water exposed.
"Jimbo" . wrote in message
...
This newsgroup has the greatest selection of experts on the web so I hope
you will excuse me for asking an off topic question about charging lead
acid
batteries.

Back in the early 60's when I worked in a service station I was taught to
remove the battery caps when charging a car battery so that's how I taught
my boys to do it. My son just finished his lift truck training course
and
they told him to leave the caps on. I checked a number of web sites and
they all say the same thing, leave the caps on.

My question is have I been doing it wrong for the last 50 years or at one
time was removing the caps a standard practice that has since been
considered unnecessay or unsafe?

Thanks in advance

Jimbo

High charge rates that the gas station battery chargers can do means that
hydrogen does get produced (that is the little bubbles that come up at a
rapid rate when charging with those chargers) and that means a nasty
explosion if the amount of hydrogen gets high. The thing was to allow the
hydrogen to easily get out of the area by first letting it get out of the
battery easily.
Many chargers can't make the current necessary to get the hydrogen rate up
to where it can become dangerous and the sealed batteries have chemicals to
adsorb the hydrogen and return it to the liquid by recombining it with the
other products of the charging.
It's one of those things that you get told to do for a particuar reason and
you extend it to all of that particular type of operation in a mindless
fashion.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works evevery time it is tried!

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

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

Hum - I have seen and heard many news accounts on these stupid models.

My understanding is the thin plates erode away and fall off in current
capacity
because of missing plate area.

Part of the issue is the protection and general design.
The battery people said it was a rush to market to limit lead in the
public.
We all know what that means. More batteries on the roads now from
these,
not excessive size plates returned in an exchange.

The effect occurs on a hot or cold day. What GM doesn't understand is
they
run high current head lamps - all lamps during driving time and that
limits
battery charge current and the multi- processor designs all sucking
power now.

I don't think much thought was put into battery design lately since the
High voltage
battery is on the way to market. Yep - we are dumping 12V after all of
these years.

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