Xref: utzoo sci.electronics:4244 rec.ham-radio:6840
Newsgroups: sci.electronics,rec.ham-radio
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: capacitance of batteries
Message-ID: <1988Nov13.001657.21990@utzoo.uucp>
Organization: U of Toronto Zoology
References: <938@ccnysci.UUCP> <8810250344.AA02429@esplanade.csri.toronto.edu> <55@sopwith.UUCP> <1638@adec23.UUCP>
Date: Sun, 13 Nov 88 00:16:57 GMT

In article <1638@adec23.UUCP> mark@adec23.UUCP (Mark Salyzyn) writes:
>Does any one know the capacitance of a 60Ah battery, or is it not possible
>to measure it ?!:-)

It's certainly measurable -- a battery is essentially a large, polarized,
highly non-linear capacitor -- but it depends on the voltage, which you
didn't specify.  60 Ah is 60*3600 coulombs of charge; capacitance is
charge/voltage.  If we assume a car battery (12V), that's an 18 kF capacitor.

(Just to head it off...  Anyone who wants to argue about whether a battery
is a capacitor should know that this was hashed out a couple of years ago.
The obvious difference is the non-linearity of the battery, but many
capacitors are detectably non-linear too.  Nonlinearity is normally felt
to be a feature in batteries and a bug in capacitors, which is why the
difference in degree.)
-- 
Sendmail is a bug,             |     Henry Spencer at U of Toronto Zoology
not a feature.                 | uunet!attcan!utzoo!henry henry@zoo.toronto.edu