Battery Education (BMW related, but not Oilhead related)

["Tom Brown" <tbrown@xxxxxxxxxxx>]

Bob, Karl:

Just wanted to let you guys know that '60 Austin Healeys were't the only
cars with batteries in the trunk.   In my semi-young days, it was common
practice to relocate the batteries of BMW 2002s to the trunk to distribute
the weight better.   It made a real difference for autocrossing and track
schools.   Later, the first M3 (E30 body designation)  was equipped with a 4
cyl, 4 valve, 2.3 liter inline that was a toned down version of their wildly
successful Formula 3 engine.  It was one of the first BMWs with a trunk
mounted battery from the factory.   Both later versions of the M3 also have
the battery in the trunk.   The 5 series V-8s also now have the batteries in
the trunk.  Batteries are heavy and putting them in the back evens out the
weight distribution quite a bit.  The new V-8s in the 5er make for pretty
cramped engine compartments, so they put the battery in the trunk to answer
that problem as well.  Since they already had the proven technology from the
M3's it was the obvious choice.    BMW seems to have this down so that
corrosion and cranking issues are non-existant. It works well nowadays.

Somewhat less successful was the Porsche 911 setup.  Engine in back and no
room for the battery in the engine bay or the back seat, so it went in the
front bonnett in the left side rocker panel.   The right side had the oil
cooler lines running up from the back of the car.   Porsche's setup was
always causing corrosion problems in the battery area.  I think they
neglected to use vent tubes in their batteries.   A vent tube gives the
corrosive gas from the battery a route to the outside through the wheel
well.  It's a sealed system as far as the inside of the car is concerned, so
the gas is not trapped in an enclosed space where it eats on the walls of
the battery compartment.

Little known facts.

- -TB


> Hi Bob,
>
> You must not have worked on a '60 Austin Healy. On mine the battery is
> not only located on the opposite side from the starter, it's located
> way back in the trunk...about as far away from the straight line 6 as
> it can get. I'd chalk it up to English design and Lucas electronics...
>
> Karl
> '94 R11RS

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End of oilheads-digest V1 #35
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