Update on Battery Warranty Enhancement for 2011 & 2012 LEAF

[opencar]

due to the recent update of the battery cap warranty, talk of the new 'hot' battery chemistry, and the maturation of the leaf battery app, i've been focusing on the relationship between Ahrs and batt capacity bars but it's great to get insight and background from your long term data collection and analysis to understand what may really be happening with the battery aging performance.

I'd say about 2% on average. Interestingly, if you look at the volatility (daily variation) of the green dots starting about 2 weeks after the update, it does appear to have improved. This supports the assertion by Andy Palmer and other Nissan reps that the sw update improved the accuracy of the instrumentation. In my case, that accuracy improvement has not so much increased the max daily capacity but rather the min daily capacity (and average daily capacity). Said differently, it appears to allow me to get to my true full capacity more consistently day to day.

[TomT]

I was told in Phoenix last month that the previous accuracy was, worst case, plus or minus 10 percent. With the P3227 update it is now plus 0 and minus 4 percent... Depending on temperature, etc., the actual error for a given vehicle and the difference between the previous software and the P3227 software might - and likely will be - much smaller...

This supports the assertion by Andy Palmer and other Nissan reps that the sw update improved the accuracy of the instrumentation.

[DaveinOlyWA]

GIDs increase in the fall, but not capacity.

Thanks for the comment. Is there any indication, however subjective, that higher GIDs translate to more range or do they simply get corrected downward more quickly?

Nothing in my data suggests that my range or capacity increased when I saw my gids increase seasonally starting at the beginning of October or degraded at a faster rate when the gids plummeted starting in March. However, I do think the latest sw update did slightly increase my available capacity/range and that was accompanied by an increase in gids.

Below is my capacity chart to date. I annotated it to try to avoid some of the confusion since the gid readings (blue dots) have a lot of volatility and in some cases almost smear into the gid readings of the prior year (i.e. variation almost as high as the annual degradation). The 2011,2012,&2013 labels and associated lines are there to help distinguish between the blue dots from year to year.

• blue dots : gids (times 0.08 to give them the same units as the wall power measurements)
  red, orange, green dots : power measured from the wall to go from 5 gids to 100% charge for 2011,2012,and 2013 respectively
  purple dots : linear fit to the power from the wall to show general average trend.

I annotated the first time my car was reset in 2012 for the Stanfield test where you can see a marked increase in the gids (blue) but no obvious increase in capacity (0 to 100 wall power (orange)).

I also annotated the sw update on 7/10/2013 where you can see a clear increase in gids (blue) and a slight increase in wall power (green). I think my data does show that capacity (green) did increase slightly for me after the sw update.

In short, the data shows that, with the exception of the sw update, capacity is declining steadily but the gids fluctuated quite dramatically with the seasons. It will be interesting to see if the seasonal variation in the gids persists this fall (if the improved accuracy and temperature compensation will translate to less seasonal variation in gids).

my thoughts; what if

** the BMS SW was skewed to where it inflated GIDs and range and charge levels in cooler weather because it felt it could take the risk and did the same in reverse in hot weather to add an additional layer of protection?

because my GID count which had been easing downward started dropping like a rock after my update. its one thing to drop from 278 to 265 over the course of 6 months but to drop from 265 to 235 in two months? like wholly molly Batman!

now part of that is weather i am guessing. getting charges in upper 230's and low 240's and I started finishing charges early (like 1 am) and restarting them before I leave in the morning when ambient is 10+º cooler and I am getting an extra half dozen GIDs so there is more room for my charge...

[TickTock]

I think you are wise to do so. Ah does seem to be a very good metric. In the sw update thread, I posted Ah over the same time and according to Ah, my capacity increased ~3% after the update. I would call that 1% delta negligible and easily within the error bars.

due to the recent update of the battery cap warranty, talk of the new 'hot' battery chemistry, and the maturation of the leaf battery app, i've been focusing on the relationship between Ahrs and batt capacity bars...

[smkettner]

Anyone going to tough it out, drag it out and get the replacement very near warranty expiration?

At the very least I would prefer to have the new "hot" battery due out next year.

[TomT]

I calculate I will hit the magic four bars missing about 3-4 months before my 4 year lease is up. So, yes, I expect to do so.

Anyone going to tough it out, drag it out and get the replacement very near warranty expiration?
At the very least I would prefer to have the new "hot" battery due out next year.

[JPWhite]

Anyone going to tough it out, drag it out and get the replacement very near warranty expiration?

At the very least I would prefer to have the new "hot" battery due out next year.

It will all depend on my ability to drive to work as the bars go out. This winter I'll probably have to switch with my wife and resort to the Altima, but if the range drops such that I can't make it during spring/summer/fall then I'll probably either trade for a 2014 LEAF or go for the $100/month syb program.

If I can squeeze out enough range to get me to work and back, then I'll hold on until the warranty kicks in, or it becomes obvious I won't qualify for the warranty replacement. The irony is that by late 2015 my workplace is moving closer to where I live AND plans to install charging equipment. From late 2015 on I could probably live with 5 bars missing Somehow have to get through next year.

We plan to replace the Altima with an Outlander PHEV when it becomes available in 2014, so my fallback plan may improve slightly. Once my employer moves, I could use either the EV or PHEV. With 4WD, the Outlander maybe the natural choice for winter anyway.

[mwalsh]

Oops! Polypore down sharply on rumors they may loose the Nissan battery contract to Japan's Asahi Kasei:

http://www.benzinga.com/news/13/09/3923 ... siness-ppo" onclick="window.open(this.href);return false;

On the plus side, making the packs cheaper AND better...that can only be good news. Unless you're a Polypore employee or investor.

Edit: Back up again in after-hours trading. Rumor turned out to be false? Who knows (yet).

[thankyouOB]

Hi everyone:

First of all, I'd like to introduce myself. I'm Brian Brockman, and I am a senior manager in corporate communications at Nissan, based at our Americas HQ in Franklin, Tenn. While LEAF is fairly new to my list of official job responsibilities, I've been engaged in the program for some time, serving as our Midwest communications manager based in Michigan since 2007....

Thank you for your time, and for your continued feedback. It's exciting to see so many enthusiastic and engaged LEAF owners. I look forward to more conversations with you in the future.

Brian

--

I wonder what happened to this guy?

[kubel]

I wonder what happened to this guy?

I think we scared him off.