ttweed said:
...I am pretty well convinced that the 9-bar/80% charge phenomena is related to battery pack degradation, and that degradation is related to temperature exposure and aging. I don't think we know enough about the SOC instrumentation implemented by Nissan to be sure how and why the changes in the "charge bar" reports happen when charging to 80%, but since I lost my first capacity bar this morning, and it came only a few days after the first 9-bar/80% reports I received after entering the third summer of service, I am pretty sure they are an early indicator of capacity loss. It took almost a year since the first 9-bar/80% report came in for our car to show a 1-bar capacity loss, but that's probably attributable to the mild climate we experience here. The 9-bar reports last year were restricted to the hot summer weather, when the temp bars were at 6 for months, but then they stopped over the winter, and started again this week when temps were still low and the car has shown only 5-bars on the temp gauge.
TT
The real question is, now that you have lost a bar, have you determined what your
actual loss of capacity is?
How?
I have seen the tenth charge bar both appear and disappear at "80%" with no charging or significant discharge, corresponding to changes in battery temperature.
From P 26 of this thread:
edatoakrun Posted: Wed Mar 06, 2013 3:02 pm
The overnight temps were a bit higher the last few nights, mid to high 40's, and sure enough, after only 17 minutes of charging to get to "80%" at 3:17 AM, the capacity bars were at 9, by the CW email.
So I figured they'd stay at 9 all day, but it got colder as the day went on.
I noticed it was about 42 f outside, so I just went down to check, and its back up to 10 bars capacity, at 4 bars temp!
That's the first time I've ever seen it go from 9 to 10, rather than the usual 10 to 9, during the daytime.
CW now correctly shows the same 10 bars, BTW. CW always accurately reflects my current dash capacity bars, after I refresh.
And, as I reported on p 25 of this thread:
edatoakrun Post subject: Re: 80% Charge only 9 bars? Posted: Wed Feb 20, 2013 7:55 pm
I had 9 bars showing after "80%" charging twice last week, for the first time since last September, coinciding with some temperature in the higher range of "4 bars".
Two nights ago it cooled down again and ten bars came back on a subsequent 80% charge, and even with slightly higher ambient temps today, I did not lose the tenth bar.
Contrast with my experience last Fall, on p 21 of this thread:
"...On the afternoon of 9/6 my 6th temp bar appeared, but for the first time in a few weeks, the 10th charge bar did not disappear. And I have had 10 bars when charging to 80% and they all stayed there, even after the 6th temp bar came on (every day I checked) ever since..."
So the set-point of my 9/10 charge bar seems to have dropped from ~75 F to ~45 F, since last Fall.
I expect the next time I see 9 bars at "80%" it may well stay there for the season, until I lose the first capacity bar, or (maybe) until Nissan "fixes" the "gauge problem".
I was wrong.
I have had 10 bars at "80%" every time since mid April, even with much higher (> 60 F) battery temperatures.
Interestingly, this corresponds to a variation of my app-reported battery capacity approaching 1% (87.29% to 88.26%, IIRC), as measured buy the LEAF app, generally increasing over the same period of time.
http://www.mynissanleaf.com/viewtopic.php?f=44&t=12789" onclick="window.open(this.href);return false;
The app is presently picking up reports of 87.93% capacity, but both my range tests and recharge capacity tests indicate a much smaller loss of capacity than that from new.
With only ~19,000 miles, but with (perhaps) more adverse climate and driving conditions than your LEAFs', I was pretty sure that I would lose a capacity bar this Spring or Summer. But seeing the recent erratic behavior of my LEAF's capacity reports from all sources, I'm not nearly so sure.
When it does lose a capacity bar, this year Summer or next, I should be able to come to a fairly good estimate of my
actual capacity loss, and of course, it presently looks likely that that percentage may be far less than "15%".