One reason that you don't want to put batteries in parallel is the possibility
of one bad battery (i.e. one with an internal short) distroying the other
battery. In addition, over time one battery is (almost) guarenteed to hold a
charge better than the other. If the batteries are wired in parallel, the
weaker battery will reduce the effectiveness of the "better" battery because the
better battery will continue to attempt to charge the weaker battery even when
the ignition is turned off.
George B.
<<forwarded message>>
to: Dennis Wilson <DWILSON@oregon.uoregon.edu>
cc: british-cars@hoosier.utah.edu sfisher@Pa.dec.com
from: sfisher@Pa.dec.com
date: Thu, 05 Dec 91 13:30:49 PST
subj: Re: To all you electronics wizards
sent: 12/05/1991 2:11 pm (PDT)
--------- **|
>Is there any reson why I can't do the following: rather than spend $50 each
>for two 6 volt batteries, could I get two small (if I can find them) 12 volt
>batteries to fit in the space the 6 volts do and connect them in parallel.
Why bother with the second 12V battery? One "group 27" battery, if I
recall the size correctly, fits in the space of either of the 6V batteries
in your car currently. Just replace the two 6Vs with a single 12V of
the right size, and if you're really clever you'll put the single 12V on
the side closest to the hot wire because it doesn't matter where you
ground it.
Go to a good, "real" auto-parts store -- something like All-Parts out
here in the San Jose area, not some place that sells 200 mph windshield
wiper fins and neon-pink shifter condoms and sixty-two different brands of
Timing Chain Rebuild In A Can, but one that actually has a passle of
batteries sitting out on a shelf. Take in your old one, find someone
who looks like he COULD pour electrolyte out of a boot if the instructions
were printed on the heel, and start matching them up. When you find one
that fits, buy it, but keep the receipt just in case. I've noticed a
surprising DOA rate on batteries.
--Scott
|