<VV> Battery Question
kaczmarek at charter.net
Sun Mar 27 14:53:11 EST 2005
> Smitty says: (In Part) It is my understanding that
> a Maintenance free battery is just another common battery with a huge
> over capacity of electrolite over the plates so it will die of old age
> before the electrolite is depleated. If that is the case it would still
> be vented and in case of over charge or over load, would still
> contaminate the air passing by.
Actually Smitty, you're not 100 percent right, but pretty close.
Maintenance free batteries came about through a change in technology of
battery plates and electrolyte solutions. Better alloys in the plates meant
a slower decompostition of said plates, and better solutions meant better
resistance to evaporation, and also a solution that kept the plates from
If you look closely at a "Maintenance Free" battery, you will see either a
case with covered raised areas (where the caps used to be), or a completely
flat case top.
In the flat case, if you look at where the top is joined to the case, there
are seams, but also two small rectangular openings---perhaps 1/16" x 1/8",
one or two on each side of the case (the width sides, not the length). Total
of 2-4 vent holes total depending on model. In the raised "pseudo cap"
models, you will find the vents there.
If you could see inside, there are channels that allow hot (boiling) fluid
to flow back to cooler parts of the battery, and the vent holes allow
overflow (a small amount) and gases to escape.
The Theory really came about because as the 70's dawned, people more and
more desired to do as little maintenance on their vehicles as possible, and
batteries especially were an item ignored by the majority of motorists until
it was too late. Originally maintenance free for 3 years, that was about as
long as the "Average" battery lasted back then anyway.
With increasing technology, now Autobone give a three year free replacement
warranty. NOBODY offered anything like that 35 years ago, not even the
advent of the Sears DieHard battery--which advertised lots of power, not how
long it would last.
There weren't any real changes in the first MF batteries, other than a small
amount of additional fluid, and an increase in the thickness and shape of
the lead pieces that connect the cells at the top of the case. when one of
these lead pieces breaks (from the effects of the acid inside), you then
have the famous "dead cell"--depending on which piece breaks, the battery is
weakened or goes "graveyard" dead. These pieces are hourglass shaped.
obviously they break , or wear away, in the center.
Johnson Controls Batteries (among them Interstate, and Autobone) have much
better cell connectors than any other batteries in the marketplace.
FWIW, the "green/red sensor window" in many batteries, especially GM AC
Delco Batteries, only presented the condition of the cell above the window.
A true marketing ploy. For the windows to work properly, a window would be
needed above each cell.
"So Hank, where the hell did you learn so much about batteries?" When
Western Auto finally stopped carrying AC Delco Batteries (a massive price
increase in 1995 prompted the move), They began to carry store brand
batteries made by Johnson Controls. I was picked to take a tour of the
Johnson Controls Plant in Greensboro, NC along with several dozen other WA
The presentation before the tour, and the expertise of the engineers and
staff at the battery plant took just about every bugaboo out of the black
box for me that day.
BTW, At the factory, I watched 3 different brand batteries being made, same
size, just different cases, on this line was group size 24.
An Interstate, a Western Auto, and am Autozone Duralast were being made, and
the ONLY difference in the batteries, was the color of the platic in the
case. WA All Black, Duralast black with white print, and the familiar
Interstate White with Green top.
An Eye opening experience.
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