Re: Battery Powered Project

From	Joe <joe@jretrading.com>
Newsgroups	comp.sys.raspberry-pi
Subject	Re: Battery Powered Project
Date	2021-01-13 22:04 +0000
Organization	JRE Trading Ltd
Message-ID	<20210113220422.68dfdff5@jresid.jretrading.com> (permalink)
References	<rtk3qv$1112$1@gioia.aioe.org> <nuh0dh-2vq01.ln1@esprimo.zbmc.eu> <rtk5ur$qi$1@gioia.aioe.org> <7ul*5x4-x@news.chiark.greenend.org.uk>

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On 12 Jan 2021 21:43:03 +0000 (GMT)
Theo <theom+news@chiark.greenend.org.uk> wrote:

> Simple Simon <please.dontspa@me.com> wrote:
> > Brilliant - many thanks - works a treat - I was almost there!!  
> 
> I'm curious... does this actually work for low battery detection?
> 
> Unless you're wiring the Pi directly across a battery that's giving
> out somewhere around 5V (for example a 6v lead acid), most of the
> time you'll have a voltage regulator between you and the battery.
> That regulator will aim to keep providing 5V as the battery is going
> flat.  When the voltage sags below 5V it means the battery is so
> empty it can't maintain that, which means it's in a very steep part
> of the voltage decline.
> 
> I'd expect it to be so steep you don't get enough time to do any
> meaningful shutdown, but I could be wrong.  What battery setup do you
> have and how does it work out in practice?
> 

Lithium cells have a linear-ish discharge curve, from 4.2V down to
around 3V. Any sensibly designed lithium battery will cut off its
output at the chosen lower bound, because if it completely discharges,
it's dead forever. Not a 'steep' decline, a 'fall off the wall' decline.

It's a good idea to have some independent means of anticipating this
point.

-- 
Joe

Thread

Battery Powered Project Simple Simon <please.dontspa@me.com> - 2021-01-12 12:14 +0000
  Re: Battery Powered Project Chris Green <cl@isbd.net> - 2021-01-12 12:40 +0000
    Re: Battery Powered Project Simple Simon <please.dontspa@me.com> - 2021-01-12 12:50 +0000
      Re: Battery Powered Project "A. Dumas" <alexandre@dumas.fr.invalid> - 2021-01-12 15:15 +0100
      Re: Battery Powered Project Theo <theom+news@chiark.greenend.org.uk> - 2021-01-12 21:43 +0000
        Re: Battery Powered Project Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2021-01-13 09:40 +0000
        Re: Battery Powered Project Jim H <invalid@invalid.invalid> - 2021-01-13 18:02 +0000
        Re: Battery Powered Project Joe <joe@jretrading.com> - 2021-01-13 22:04 +0000
          Re: Battery Powered Project Theo <theom+news@chiark.greenend.org.uk> - 2021-01-13 23:37 +0000
            Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-14 00:43 +0000
            Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 03:59 +0000
            Re: Battery Powered Project Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-14 10:18 +0000
              Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 11:04 +0000
                Re: Battery Powered Project Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-14 11:46 +0000
                Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 12:21 +0000
                Re: Battery Powered Project Ahem A Rivet's Shot <steveo@eircom.net> - 2021-01-14 12:38 +0000
                Re: Battery Powered Project David Higton <dave@davehigton.me.uk> - 2021-01-14 14:17 +0000
                Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 14:28 +0000
                Re: Battery Powered Project David Higton <dave@davehigton.me.uk> - 2021-01-16 20:09 +0000
                Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-17 07:19 +0000
                Re: Battery Powered Project David Higton <dave@davehigton.me.uk> - 2021-01-17 15:57 +0000
                Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-18 07:05 +0000
                Re: Battery Powered Project David Higton <dave@davehigton.me.uk> - 2021-01-18 14:14 +0000
                Re: Battery Powered Project John Aldridge <jpsa@cantab.net> - 2021-01-17 17:52 +0000
              Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-14 12:56 +0000
              Re: Battery Powered Project Theo <theom+news@chiark.greenend.org.uk> - 2021-01-14 13:46 +0000
                Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 14:26 +0000
          Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 03:46 +0000
            Re: Battery Powered Project Folderol <general@musically.me.uk> - 2021-01-14 09:23 +0000
              Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-14 11:04 +0000
                Re: Battery Powered Project Folderol <general@musically.me.uk> - 2021-01-14 17:48 +0000
            Re: Battery Powered Project Jim H <invalid@invalid.invalid> - 2021-01-18 17:07 +0000
              Re: Battery Powered Project Joe <joe@jretrading.com> - 2021-01-18 20:33 +0000
                Re: Battery Powered Project Jim H <invalid@invalid.invalid> - 2021-01-21 20:36 +0000
  Battery Powered Project nospam.Vincent.Coen@f1.n250.z2.binkp.net (Vincent Coen) - 2021-01-12 14:35 +1300
  Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-12 16:40 +0000
    Re: Battery Powered Project The Natural Philosopher <tnp@invalid.invalid> - 2021-01-13 13:56 +0000
      Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-13 15:12 +0000
        Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-16 12:24 +0000
          Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-16 17:53 +0000
            Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-16 20:39 +0000
              Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-16 22:33 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-16 23:30 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-16 23:52 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-17 10:39 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-17 14:32 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-18 13:20 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-18 13:41 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-18 14:02 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-18 15:15 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-19 13:46 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-19 15:24 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-19 15:34 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-19 16:21 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-19 17:18 +0000
                Re: Battery Powered Project Richard Kettlewell <invalid@invalid.invalid> - 2021-01-19 19:31 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-20 10:12 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-19 22:15 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-20 10:03 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-20 10:49 +0000
                Re: Battery Powered Project Chris Elvidge <chris@mshome.net> - 2021-01-20 11:29 +0000
                Re: Battery Powered Project A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-20 12:18 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-20 13:02 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-20 15:49 +0000
                Re: Battery Powered Project Richard Kettlewell <invalid@invalid.invalid> - 2021-01-20 16:54 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-20 17:19 +0000
                Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-21 10:24 +0000
                Re: Battery Powered Project A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-20 12:18 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-20 13:18 +0000
                Re: Battery Powered Project Chris Elvidge <chris@mshome.net> - 2021-01-20 14:14 +0000
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-20 14:51 +0000
                Re: Battery Powered Project A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-20 14:45 +0000
                Re: Battery Powered Project A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-20 14:44 +0000
                Re: Battery Powered Project Richard Kettlewell <invalid@invalid.invalid> - 2021-01-20 15:07 +0000
                Re: Battery Powered Project "A. Dumas" <alexandre@dumas.fr.invalid> - 2021-01-20 16:38 +0100
                Re: Battery Powered Project Chris Elvidge <chris@mshome.net> - 2021-01-20 15:45 +0000
                Re: Battery Powered Project druck <news@druck.org.uk> - 2021-01-21 10:07 +0000
                Re: Battery Powered Project "A. Dumas" <alexandre@dumas.fr.invalid> - 2021-01-21 12:30 +0100
                Re: Battery Powered Project druck <news@druck.org.uk> - 2021-01-21 13:09 +0000
                Re: Battery Powered Project Anssi Saari <as@sci.fi> - 2021-01-22 10:08 +0200
                Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-22 10:29 +0000
                Re: Battery Powered Project Chris Green <cl@isbd.net> - 2021-01-22 10:25 +0000
                Re: Battery Powered Project Kees Nuyt <k.nuyt@nospam.demon.nl> - 2021-01-19 17:03 +0100
                Re: Battery Powered Project A. Dumas <alexandre@dumas.fr.invalid> - 2021-01-17 01:09 +0000
            Re: Battery Powered Project Chris Elvidge <chris@mshome.net> - 2021-01-17 11:48 +0000
              Re: Battery Powered Project Pancho <Pancho.Dontmaileme@outlook.com> - 2021-01-17 12:11 +0000
              Re: Battery Powered Project Martin Gregorie <martin@mydomain.invalid> - 2021-01-17 14:43 +0000
            Re: Battery Powered Project Chris Elvidge <chris@mshome.net> - 2021-01-17 11:52 +0000
              Re: Battery Powered Project Andy Burns <usenet@andyburns.uk> - 2021-01-17 13:53 +0000

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