I love my Leaf and drive it all over town, occasionally stretching it to arrive at my next charging location with less than 20% real SoC left (last bar on the Leaf's Guess-o-Meter) and I tend to charge mostly to 80% and rarely (once a month or so) to 100%. I still see the measured capacity degrade on a weekly basis as reported by the BMS (measured Ah capacity) so I tend to believe that while Lead-Acid acted much like an organic sponge, the Lithium cells act much more like a bucket: use it or not, capacity does not change much besides the inevitable gradual deterioration due to the irrepairable defects building up over time, causing both capacity loss and internal resistance increase and possibly eventually an increase in self-discharge. Actually Li-Ion works more like a Hydro dam: slowly silt builds up in the lake, reducing the capacity of the reservoir.
Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info http://www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Peri Hartman via EV Sent: Wednesday, October 05, 2016 8:17 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] To fully charge or not to fully charge that isthequestion Could be, but I don't think anyone has brought up that theory before. That would mean that people who charge and discharge between 80% to 60% should see significant degradation whereas those who discharge to 20% should not. Can anyone corroborate that? Peri ------ Original Message ------ From: "Thos True" <evpa...@gmail.com> To: "Peri Hartman" <pe...@kotatko.com>; "Electric Vehicle Discussion List" <ev@lists.evdl.org> Sent: 05-Oct-16 8:10:00 AM Subject: Re: [EVDL] To fully charge or not to fully charge that isthequestion >Peri, > >My thinking on the degradation has to do with the fact that most people >do not actually discharge the cells below 50 or 60 percent. >I learned from some of the people involved with the lithium cells that >it is best to think of them as a "sponge". That is, if you leave a >sponge soaking in a bucket, it rots very quickly (always plugged in or >charged), and if you leave it on a shelf all the time, it becomes very >hard, and takes a very long time to re-hydrate (prolonged low charge). >However is you wring it out on a regular basis, lasts for a very long >time (regular full charges and discharges). This is why it was >recommended to fully discharge ie. wring out (according to the >instrumentation) once per month. >I know that it worked well for me. > >-Tom > >On Wed, Oct 5, 2016 at 7:10 AM, Peri Hartman via EV <ev@lists.evdl.org> >wrote: >>Something doesn't make sense, here. No doubt you prolonged the battery >>capacity by not charging and discharging fully, per the engineer's >>advice. >> >>But according to what others have said, if you consistently charge to >>80% and discharge to 20%, you should see very little or no capacity >>degradation with LiFePos. Yet the vast majority of Leaf owners do see >>significant degradation and never see thermal runaway. >> >>So, either LiFePos need even a smaller margin of operation, say 35% to >>65%, or what the engineer told you isn't completely true. Or there's >>some other significant factor in the situation. >> >>Peri >> >>------ Original Message ------ >>From: "Thos True via EV" <ev@lists.evdl.org> >>To: "Cor van de Water" <cwa...@proxim.com>; "Electric Vehicle >>Discussion List" <ev@lists.evdl.org> >>Sent: 05-Oct-16 7:00:20 AM >>Subject: Re: [EVDL] To fully charge or not to fully charge that >>isthequestion >> >>>I'm not sure why this keeps coming back to roost. Some people on this >>>list >>>may recall the same conversation back in the spring of 2011, where I >>>contacted Nissan about the 80% issue. I received a phone call from >>>one of >>>the engineers in Tennessee. He understood my confusion and expressed >>>some >>>frustration at their end, explaining that they designed the on board >>>battery management system to protect the batteries. Doing so by never >>>letting the batteries charge above 80% (which shows as the full 100% >>>on the >>>instrumentation), and never discharging below 20% (which shows as >>>0%). >>>Explaining that if you let the battery pack get below 10%, it would >>>typically brick (not allow a charge), and above 90%, that your could >>>experience a thermal even ( Thermal runaway & fire). >>>The final recommendation from him was to discharge the pack to 10 >>>miles or >>>so in range (according to the instrumentation), and fully recharge >>>about >>>once a month to "refresh" the battery. I followed his advice, and >>>after 39 >>>months and 56,000 miles, (the end of the lease), the pack was still >>>above >>>98% capacity, which seemed to surprise the service department at the >>>dealership where we turned it in at. >>>I suspect that some of the degradation that we experienced may have >>>been >>>due to some of the fast chargers that we used toward the end of the >>>lease, >>>but have no way to be sure of that. >>> >>>Tom True >>> >>>On Tue, Oct 4, 2016 at 11:39 PM, Cor van de Water via EV >>><ev@lists.evdl.org> >>>wrote: >>> >>>> Let's try that *with* the link: >>>> >>>>https://techcrunch.com/2016/09/29/tales-from-a-tesla-model-s-at-200k -mil >>>> es/ >>>> >>>> >>>> Cor van de Water >>>> Chief Scientist >>>> Proxim Wireless >>>> >>>> office +1 408 383 7626 Skype: cor_van_de_water >>>> XoIP +31 87 784 1130 private: cvandewater.info >>>> >>>> http://www.proxim.com >>>> >>>> This email message (including any attachments) contains >>>>confidential and >>>> proprietary information of Proxim Wireless Corporation. If you >>>>received >>>> this message in error, please delete it and notify the sender. Any >>>> unauthorized use, disclosure, distribution, or copying of any part >>>>of >>>> this message is prohibited. >>>> >>>> >>>> -----Original Message----- >>>> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Cor van de >>>> Water via EV >>>> Sent: Tuesday, October 04, 2016 11:28 PM >>>> To: Electric Vehicle Discussion List >>>> Subject: Re: [EVDL] To fully charge or not to fully charge that >>>> isthequestion >>>> >>>> Here is the article about the 200k mi Tesla (in 1 year) Note that >>>> Tesloop is actually aiming at putting 400k mi on their cars each >>>>year, >>>> so the 8 year warranty on battery and drivetrain would give them ~3 >>>> million miles under warranty... >>>> Their website has a blog with a few of the details, including an >>>>early >>>> front motor replacement under warranty. >>>> >>>> Cor van de Water >>>> Chief Scientist >>>> Proxim Wireless >>>> >>>> office +1 408 383 7626 Skype: cor_van_de_water >>>> XoIP +31 87 784 1130 private: cvandewater.info >>>> >>>> http://www.proxim.com >>>> >>>> This email message (including any attachments) contains >>>>confidential and >>>> proprietary information of Proxim Wireless Corporation. If you >>>>received >>>> this message in error, please delete it and notify the sender. Any >>>> unauthorized use, disclosure, distribution, or copying of any part >>>>of >>>> this message is prohibited. >>>> >>>> >>>> -----Original Message----- >>>> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Cor van de >>>> Water via EV >>>> Sent: Tuesday, October 04, 2016 2:06 PM >>>> To: Willie2; Electric Vehicle Discussion List >>>> Subject: Re: [EVDL] To fully charge or not to fully charge that is >>>> thequestion >>>> >>>> Willie, >>>> Not dynamically, just a one-time upgrade (dealer visit required). >>>> Many Leaf owners who lost the 4th bar and thought they qualified >>>>for the >>>> warranty battery replacement were miffed to see the dealer really >>>> enforcing the Nissan requirement that the warranty will only be >>>>honored >>>> after the mandatory re-calibration of the 12 battery bar gauge. >>>>Most >>>> owners found out that after re-calibration their earlier 4 bar >>>>loser no >>>> longer showed 4 bars lost so they no longer qualified unless they >>>>would >>>> again see 4 bars lost on the re-calibrated gauge. The first bar >>>>does not >>>> disappear until 15% is lost and each subsequent bar should stand >>>>for >>>> 6.25% so in theory you need a battery degraded to just over 66% of >>>> nominal capacity to qualify if the gauge will indeed drop to 4 bars >>>> right at that point. But reports I have seen of Ah capacity >>>>degradation >>>> suggest that the loss of the 4th bar happens later. >>>> I found it significant that Leafs can lose more than 40% capacity >>>>in >>>> about 50k mi while some Tesla drops only 6% in 200k mi. >>>> >>>> Of course this is only one sample with a specific usage pattern, >>>>but I >>>> highly doubt an expansion of the samples will give different >>>>results, >>>> we'll see. >>>> >>>> Cor van de Water >>>> Chief Scientist >>>> Proxim Wireless >>>> >>>> office +1 408 383 7626 Skype: cor_van_de_water >>>> XoIP +31 87 784 1130 private: cvandewater.info >>>> >>>> http://www.proxim.com >>>> >>>> This email message (including any attachments) contains >>>>confidential and >>>> proprietary information of Proxim Wireless Corporation. If you >>>>received >>>> this message in error, please delete it and notify the sender. Any >>>> unauthorized use, disclosure, distribution, or copying of any part >>>>of >>>> this message is prohibited. >>>> >>>> >>>> -----Original Message----- >>>> From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Willie2 >>>>via EV >>>> Sent: Tuesday, October 04, 2016 11:18 AM >>>> To: Electric Vehicle Discussion List >>>> Subject: Re: [EVDL] To fully charge or not to fully charge that is >>>>the >>>> question >>>> >>>> On 10/04/2016 12:29 PM, Cor van de Water via EV wrote: >>>> > on the battery as the Leaf *does* degrade its battery by 40% to >>>>approx >>>> >>>> > 60% capacity in approx 50k mi in warmer climates (that is the >>>>point >>>> > where Nissan gives a warranty battery replacement, even though >>>>they >>>> > promised 70% but re-calibated the battery to lose the 4th bar >>>>around >>>> 60% >>>> > capacity and triggering the warranty if it occurs within the >>>>warranty >>>> > limits for time and mileage.) >>>> When I first got my Leaf, I was astonished at how crappy the >>>> instrumentation is/was. Coming from the conversion world, I >>>>expected to >>>> >>>> see, or find out, how much energy went into the battery and how >>>>much >>>> came out. Instead, I had these twelve "bars". Unacceptable >>>>granularity. >>>> Later, I found the "bars" were not even of equal value. >>>> After some pondering, I came to the conclusion that Nissan did >>>>things in >>>> >>>> that way to hide information from their customers. What other >>>> explanation could there be? >>>> >>>> Even more astonishing is how Leaf owners accept the situation and >>>>speak >>>> of almost meaningless "bars". I'm not surprised to learn that >>>>Nissan >>>> dynamically recalibrates "bars" to manage their warranty threshold. >>>> >>>> _______________________________________________ >>>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>>> Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV >>>>drag >>>> racing at NEDRA >>>> (http://groups.yahoo.com/group/NEDRA) >>>> >>>> _______________________________________________ >>>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>>> Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV >>>>drag >>>> racing at NEDRA (http://groups.yahoo.com/group/NEDRA) >>>> >>>> _______________________________________________ >>>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>>> Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV >>>>drag >>>> racing at NEDRA (http://groups.yahoo.com/group/NEDRA) >>>> >>>> _______________________________________________ >>>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>>> Read EVAngel's EV News at http://evdl.org/evln/ >>>> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/ >>>> group/NEDRA) >>>> >>>> >>> >>> >>>-- >>>Remember, it is not that the glass is half empty, in reality, the >>>glass is >>>merely twice the size that it needs to be! -TNT'82 >>>-------------- next part -------------- >>>An HTML attachment was scrubbed... >>>URL: >>><http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20161005/5 94baeca/attachment.htm> >>>_______________________________________________ >>>UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>>http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>>Read EVAngel's EV News at http://evdl.org/evln/ >>>Please discuss EV drag racing at NEDRA >>>(http://groups.yahoo.com/group/NEDRA) >>> >>> >> >>_______________________________________________ >>UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>Read EVAngel's EV News at http://evdl.org/evln/ >>Please discuss EV drag racing at NEDRA >>(http://groups.yahoo.com/group/NEDRA) >> > > > >-- >Remember, it is not that the glass is half empty, in reality, the glass >is merely twice the size that it needs to be! -TNT'82 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20161005/5dc9 924d/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
