Strike Three!

May 30, 2016

Mark D Larsen

3rd Capacity Bar Loss
(click to enlarge)

When I got in my LEAF this afternoon, I noticed that its capacity gauge had lost its 3rd bar. As you can see in the photo below on the left, that loss occurred after 40,438 miles and 50 months of ownership. The LEAFStat readout below on the right shows that the capacity was at 71.73% (47.53 Ahr):

Miles driven
(click to enlarge)

Capacity remaining
(click to enlarge)

As readers will recall, the 2nd bar vanished 9 months and 3 weeks ago. One might therefore wonder if I will lose the 4th bar after that same amount of time, right before my LEAF’s 5-year anniversary, and thus qualify for a free battery replacement under Nissan’s capacity warranty. However, when I plot the polynomial curve from all my LEAFStat readings to date, that possibility does not look promising: so far it looks like I’ll barely miss the cutoff.

What concerns me most is that today’s capacity readout is again lower than when the 3rd bar was supposed to vanish —just like had happened with the 2nd bar loss. And another EV advocate told me just last week that he also lost his 2nd bar at nearly a percentage lower than anticipated. This is worrisome, for I thought that Nissan was going to “tighten” those thresholds with its P3227 software upgrade to make the capacity gauge more accurate. Was I remembering those percentages incorrectly? Since bars are disappearing at lower percentages than anticipated, I decided that I had better take another look at the Nissan Wiki Page to make sure. Yes, that section shows a table of the percentages when each capacity bar is supposed to turn off: 78.75% for the 2nd bar, and 72.50% for the 3rd.

Perhaps the Wiki’s percentages were inaccurate? The relevant footnote (6) states that the table comes from the Nissan LEAF Service Manual, page MWI-23, so I decided to check the original source. I scoured the web to try to find the manual, and finally found a copy of the MWI section. To my great surprise, below on the left is page 23, which doesn’t give any percentages for capacity bar loss:

MWI p. 23 (revised!)
(click to enlarge)

MWI p. 23 (original!)
(click to enlarge)

WHAT...!? How could the Wiki have made such a mistake? But then I noticed that the footer on that page states: “Revision: 2014 June.” Uh... June 2014...? Hmmm. That date seemed familiar to me, so I checked my files: that was when Nissan announced the price of replacement battery packs, as promised with the new capacity warranty.

Okay: color me paranoid. Surely Nissan wouldn’t have actually loosened —rather than tightened— the capacity bars’ thresholds with its software upgrade, and then deleted the percentages on that page of the service manual, lest anyone notice the discrepancies. Would they...!?! The only way to know for sure would be to locate a copy of the original 2011 Service Manual. I stopped by my local dealer to see if the technicians still had one, but to no avail: Nissan updates those manuals online overnight, and the service department could no longer access the original LEAF manual.

Nonetheless, the cyberdeities smiled on me: after more sleuthing I finally managed to locate the 2011 manual in an obscure corner of the web. You can see up above on the right that the original page MWI-23 did, indeed, provide a table with the percentages cited in the Nissan Wiki. The threshold percentages I had remembered were accurate!

Perhaps, however, my experience was a fluke...? Maybe other LEAF owners had lost their capacity bars at the originally published percentages. I therefore consulted the Wiki page with a compiled list of real world bar losses. Because owners lacked the ability to check their own capacity percentages until Leaf Spy Pro and LEAFStat were available, I could only compare the results reported on that page during the last couple of years. Regardless, the pattern was clear: not once did a bar vanish at the original threshold, let alone at a higher percentage, as you can see in these tables:

So now you can also color me... appalled. And very sad. What other conclusion can one draw except that Nissan purposely reprogrammed the thresholds, and then obliterated the original percentages, knowing fully well that the bars would henceforth turn off when their capacity was lower than what owners had been led to believe? It was damn clever of Nissan to base its warranty not on an actual capacity percentage, but on the gauge bars —which the automaker could easily reconfigure with a software update.

Given these results, I am now convinced that my next bar likewise won’t disappear until my pack has deteriorated well below its originally published threshold. As projected in the polynomial trajectory up above, if I won’t lose the oh-so-crucial 4th bar at 66.25% before the warranty expires, I most certainly won’t qualify for a replacement at an even lower percentage. I hope I'm wrong, but you’ll have to forgive me if I don’t hold my breath.