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Re: Battery Powered Project

From The Natural Philosopher <tnp@invalid.invalid>
Newsgroups comp.sys.raspberry-pi
Subject Re: Battery Powered Project
Date 2021-01-14 12:21 +0000
Organization A little, after lunch
Message-ID <rtpd10$7hp$1@dont-email.me> (permalink)
References (4 earlier) <20210113220422.68dfdff5@jresid.jretrading.com> <6ul*le+-x@news.chiark.greenend.org.uk> <20210114101857.57aca4dab56bca0a4e589a4a@eircom.net> <rtp8gn$55d$4@dont-email.me> <20210114114623.0b54c475f1741b48b8f13658@eircom.net>

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On 14/01/2021 11:46, Ahem A Rivet's Shot wrote:
> On Thu, 14 Jan 2021 11:04:55 +0000
> The Natural Philosopher <tnp@invalid.invalid> wrote:
> 
>> On 14/01/2021 10:18, Ahem A Rivet's Shot wrote:
>>> On 13 Jan 2021 23:37:18 +0000 (GMT)
>>> Theo <theom+news@chiark.greenend.org.uk> wrote:
>>>
>>>> Joe <joe@jretrading.com> wrote:
>>>>> 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.
>>>>
>>>> But lithium ion cells don't work for this application.  We need 5V.
>>>> One cell is too little, two cells is too much.
>>>
>>> 	One cell and a DC-DC converter to give you a regulated supply,
>>> monitor the cell so you can shut down (well) before there's too little
>>> to run the converter.
>>>
>> It's slightly simpler and more efficient to use a step down from two
>> cells.
> 
> 	It's only simpler if you look at what's on the converter board :)
> 
No, that's not true. To step up you need to use a buck converter with a 
choke big enough to store energy to push the voltage up. To step down 
you only need a choke to smooth HF ripple, and transistor efficiency 
goes up with voltage and down with current, so that's a win win too.

-- 
"Corbyn talks about equality, justice, opportunity, health care, peace, 
community, compassion, investment, security, housing...."
"What kind of person is not interested in those things?"

"Jeremy Corbyn?"

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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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