Groups > sci.electronics.design > #454275

Re: Simple Low Voltage Shut Down

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From	Winfield Hill <hill@rowland.harvard.edu>
Newsgroups	sci.electronics.design
Subject	Re: Simple Low Voltage Shut Down
Date	30 Mar 2017 14:31:40 -0700
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Tim Wescott wrote...
>
>On Thu, 30 Mar 2017 13:18:33 -0700, Winfield Hill wrote:
>
>> Tim Wescott wrote...
>>>
>>>Second, you want some hysteresis, or at a certain level of charge the
>>>thing will start madly turning on and off.  Without hysteresis the
>>>current will get shut off, the battery voltage will rebound, the circuit
>>>will turn on, the battery voltage will get pulled low, and the cycle
>>>will repeat.
>> 
>>  True, but a 1-volt battery with no load doesn't rebound very much.  If
>>  the hysteresis is, say, 0.25V, it should stay off.
>
>An Internet acquaintance of mine who used to be a battery engineer for GE 
>claimed that nearly-fully-discharged NiCd cells would rebound to 1.2V if 
>you gave them enough time, even if they couldn't deliver any significant 
>charge.
>
>But -- I'd have to test that theory on alkalines.

 Alkalines are rather different, in a useful way.
 Their open-circuit voltage drops from 1.55V to
 1.0 or 0.9V, etc, as they're depleted, providing
 a convenient way to evaluate their condition.


-- 
 Thanks,
    - Win

Thread

Simple Low Voltage Shut Down Robert Miller <robert.miller@teledyne.com> - 2017-03-30 18:21 +1100
  Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 05:13 -0700
    Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 10:20 -0700
      Re: Simple Low Voltage Shut Down Tim Wescott <seemywebsite@myfooter.really> - 2017-03-30 14:39 -0500
    Re: Simple Low Voltage Shut Down Robert Miller <robert.miller@teledyne.com> - 2017-04-01 07:42 +1100
      Re: Simple Low Voltage Shut Down rickman <gnuarm@gmail.com> - 2017-03-31 18:03 -0400
        Re: Simple Low Voltage Shut Down Robert Miller <robert.miller@teledyne.com> - 2017-04-01 10:35 +1100
          Re: Simple Low Voltage Shut Down rickman <gnuarm@gmail.com> - 2017-03-31 19:49 -0400
      Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-31 17:56 -0700
        Re: Simple Low Voltage Shut Down Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-04-01 11:17 -0400
  Re: Simple Low Voltage Shut Down John Larkin <jjlarkin@highlandtechnology.com> - 2017-03-30 07:14 -0700
  Re: Simple Low Voltage Shut Down Tim Wescott <tim@seemywebsite.com> - 2017-03-30 12:19 -0500
    Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 13:18 -0700
      Re: Simple Low Voltage Shut Down Tim Wescott <seemywebsite@myfooter.really> - 2017-03-30 15:52 -0500
        Re: Simple Low Voltage Shut Down Winfield Hill <hill@rowland.harvard.edu> - 2017-03-30 14:31 -0700
          Re: Simple Low Voltage Shut Down mike <ham789@netzero.net> - 2017-03-30 15:02 -0700

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