I agree with the following and if you have a chance talk to
a local Interstate Battery salesman, they will tell you that
the new 12 volt batteries are being built with modern
technogly (yes it's true) and the 6 volt batteries still are
manufactured in the old tradtional way. Seems that they sell
so few that they have no plans to change. Here in Phoenix
they only sell about two dozen 6 volt batteries (in our
required size) a year vs. the group 26's.
Regards, Jon Nyhus
DANMAS@aol.com wrote:
> While we are on the subject of 6 volt vs 12 volt
> batteries, I thought I would
> offer the following bit of fluff.
>
> I am going to start off by saying something now that will
> not only surprise
> you, but will cause you to doubt my sanity - Every MG TA,
> TB, TC, TD, TF, A,
> B, and C has, and came from the factory with, ONE, repeat,
> ONE, 12 Volt
> battery. It is also possible that your MG came from the
> factory with two 6
> volt batteries. Obviously, now, I am going to have to
> explain myself.
>
> When you return from the store with two 6 volt batteries
> under your arm, and
> install them in your car, the instant you make the last
> connection, you have,
> BY DEFINITION, a single 12 volt battery. Your single 12
> volt battery just
> happens to be in two boxes instead of one. Further
> explaination is in order.
>
> Take a close look at the outside of one of your batteries.
> You will note
> slight vertical depressions, equally spaced, on the front
> and back of the
> case. These depressions are from the divider walls inside
> the battery, which
> divide it into three cells. Each of these three cell
> produce 2 volts. They
> are interconnected internally to the battery in series to
> produce 6 or 12
> volts. On older batteries, the connectors were visible on
> the outside of the
> case, but they are hard to spot on newer ones. By
> DEFINITION, a battery is
> one or more cells, wired in series, parallel, or a
> combition of both, to
> produce either more voltage or current than a single cell
> is capable of. On
> the shelf, each box is a 6 volt battery, consisting of
> three 2 volt cells in
> series. When you connect them, they become one 12 volt
> battery, with six 2
> volt cells in series, in two containers.
>
> Now, let's do a thought experiment. Imagine placing the
> two 6 volt battery
> boxes side by side so that they touch each other. Next,
> connect the adjacent
> terminals of the two batteries together, negative to
> positive. Since these
> batteries are touching, we don't need two end walls where
> they touch. Let's
> remove one of them, and glue the two cases together. Now
> that the two cases
> are glued solid to one another, we can put the jumper
> connection inside the
> case, just like the others. Now, stand back and look at
> what you have. It
> looks a lot like one 12 volt battery, doesn't it.
>
> The whole point of this exercise is to show that there is
> no inherent
> difference between using two 6 volt batteries vs one 12
> volt. However, all
> other things being equal, a larger battery will have more
> storage capacity
> than a smaller one. If we replace our two 6 volts with one
> 12 volt of the
> same size as one 6 volt, and the batteries are of
> identical design, we have
> obviously reduced our capacity. Refering to the above
> experiment, the
> physical size is now half that of before. (I don't think
> it is safe to say
> we have reduced capacity by 1/2, though. There are other
> parameters at play
> here).
>
> The flaw in the logic above is this - things are seldom,
> if ever, equal! A
> good design 12 volt battery will provide more cranking
> power than two poorly
> designed 6 volt batteries, even if each 6 volt is the same
> size as the one 12
> volt. And vice-versa. It is very easy to buy a 12 volt
> battery that will fit
> in the space allowed and provide ample cranking capacity
> for the intended
> purpose. The fact that two sixes might provide more is of
> no concern if you
> don't need the extra capacity. There is a lot to be said
> for having only one
> battery to care for.
>
> Don't be taken in by the claim that two 200 amphour 6 volt
> batteries will
> have a 400 amphour rating. As you can see from the above
> experiment, the same
> 200 amps flows through both boxes. Battery 1 will use up
> its 200 amphours at
> exactly the same time as battery 2. Which is exactly the
> same time a single
> 12 volt, 200 amphour rated, battery would have used up its
> 200 amphours. When
> you decide on batteries for your MG, go by the ratings for
> a single battery,
> whether you are using one 12 volt, or two 6 volt
> batteries. For our MGs, it
> is simply a matter of choice. There is no compelling
> reason for either
> option.
>
> Personally, I have a 12 volt battery in my '74, and I have
> a storage bin in
> the other space. For me, the choice was one of
> convenience.
>
> Dan Masters,
> Alcoa, TN
>
> '71 TR6---------3000mile/year driver, fully restored
> '71 TR6---------undergoing full restoration and Ford 5.0
> V8 insertion - see:
>
> http://www.sky.net/~boballen/mg/Masters/
> '74 MGBGT---3000mile/year driver, original condition
> '68 MGBGT---organ donor for the '74
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