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Groups > sci.electronics.design > #454287
| From | mike <ham789@netzero.net> |
|---|---|
| Newsgroups | sci.electronics.design |
| Subject | Re: Simple Low Voltage Shut Down |
| Date | 2017-03-30 15:02 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <objv66$msr$1@dont-email.me> (permalink) |
| References | <Nl2DA.428151$fZ.218528@fx41.am4> <-vWdnXOqofBu8kDFnZ2dnUU7-RednZ2d@giganews.com> <objtfs02uj7@drn.newsguy.com> |
On 3/30/2017 2:31 PM, Winfield Hill wrote: > 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. > > Is there a simple explanation for why this happens? It's a chemical reaction with voltages determined by chemistry/physics. I can understand why the series resistance would increase as the reagents are "used up". But, why does the open-circuit voltage change? I don't mean to hijack the thread, just a few words in layman's terms or a link will suffice. Thanks,
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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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