Path: ...!eternal-september.org!feeder3.eternal-september.org!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: liz@poppyrecords.invalid.invalid (Liz Tuddenham)
Newsgroups: sci.electronics.design
Subject: Re: Battery (SLA) modeling
Date: Fri, 13 Dec 2024 15:54:44 +0000
Organization: Poppy Records
Lines: 26
Message-ID: <1r4ih4v.151b2dlgylpneN%liz@poppyrecords.invalid.invalid>
References: <vjgltr$394qj$1@dont-email.me>
X-Trace: individual.net /KO6e86Ag7+eEY7Y/3LJBgMpwkOOnNzOHTcmTItCCHd5yDQtw8
X-Orig-Path: liz
Cancel-Lock: sha1:iS0WTe5XB2rFpTqXD7muRIlEO0Y= sha256:m8zPNxNPMtT25gACQRjCjbV27k25BwvdfJpQwZZAW6g=
User-Agent: MacSOUP/2.4.6
Bytes: 1822

Don Y <blockedofcourse@foo.invalid> wrote:

> At a fixed time and temperature, is it safe to model a battery as a
> fixed voltage source behind a series resistance?  Possibly, additionally,
> a parallel RC to cover transients?
> 
> In particular, does the model need to change based on whether the
> battery is being charged or discharged?  (i.e., to estimate that
> series resistance)

Design for the worst possible series resistance and then some.  I have
been caught out by that a couple of times.  Screaming and apparently
untraceable audio instability in the middle of doing the P.A. for a
public event is highly embarassing. ("Yes, we put in a new battery - oh
no, someone must have put the old one back in the box with the others -
terribly sorry!")

Also, whatever the manufacturers clain for the battery capacity, design
for half that amount.  Batteries don't last forever but your customers
will assume they do and won't want to change them until they are well
below half capacity.

-- 
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk