Car Battery capacity

[William Magliocco]

I haven't read the whole thread, but I think I see a
problem:

"So 0.33A for a 700A-H battery sounds like 2100 hours
x 50% = 1050 hours."

Someone has mistaken the "700" figure for amp-hours. 
The "700" is probably Cranking Amps (CA) or Cold
Cranking Amps (CCA).  Just looked at a bunch of
batteries at a Sears yesterday and that is a pretty
typical figure for CA/CCA performance.

They are NOT the same as Amp-Hours.  Based on past
surveys, figure your car battery to be somewhere
around 50~75 Amp Hours.  That is at least 90% less
than the CA/CCA figures.

When shopping for batteries, CCA is always lower than
CA, as CCA is measured at 0 degrees C, IIRC, and CA is
measured at 20 Deg. C or better.

Car batteries are seldom specified with their AH
capacity, as their job is to start your car.  Deep
cycle marine batteries are more likely to be spec'd in
AH due their application.  Also, there are differences
in how deep cycle and car batteries are made owing to
the differences in how they are used.

Sorry to bore the gallery...

Bill M., BSEE & a bunch of TV Engineering & IT certs
Atlanta.



 
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