Ok, I know its been a while since I have posted anything and I admit I was waiting on "something" to report. As we know, 40 kwh packs seem to have major adjustments to battery status every 90 days or so. My car was built on 1/2018 and it had adjustments on
April 12, 2018 lasted one day and lost .76 ahr. Now that doesn't sound like much but .66% exceeded what I had lost in the first 4500 miles.
July 6, 2018 and July 17, 2018 but was on vacation so don't know exactly when but was at least two days since both days above recorded drops. Remember stats are recorded the following day so the July 6th drop was recorded July 17th while July 17th drop was recorded July 18th. Loss was 1.44% ahr
October 10-12, 2018 which lasted 3 days. Lost 1.39 ahr
January 8-12, 2019 for 5 days. Lost 1.79 ahr
April 9-12, 2019 for 4 days. Lost 1.06 ahr
If wondering; these 5 adjustments accounted for 6.44 of the total 8.79 ahr lost since new (115.05) So if these adjustments weren't happening, I was looking at a very long happy life with this car.
Now, I was tracking my 100,000 mile projection and on April 11th, I was projected to be at less than 57% SOH at 100,000 miles which means I would have easily qualified for a warranty exchange that would have most certainly come with a better, more robust pack. This caused me to heavily lean to purchasing at the end of the lease. With sales tax breaks on used EVs combined with a very attractive $9600 residual, it seemed like a win win.
Time to Experiment
After the April 2019 adjustment, I decided it was time to experiment and as luck would have it; Late Spring and Early Summer was the perfect time to do it. I decided to charge as much as possible at home keeping SOC no higher than 70% and batt temps no higher than 90ยบ. Of course, 3 months is a long time and there were a handful of QCs in there but a fraction of the normal. Then the July adjustment happened and everything changed.
July 8-11, 2019. Up until this point, my stats had never risen. Not even .01% on either ahr or SOH (Hx bounces around more than a Superball) so saying "shocked" is understating my reaction by quite a bit as I watched my ahr RISE 1.12 over the 4 day period. I was now back to April 2019 levels (day before April adjustment) just like that!
But I wasn't about to get too excited. It was a single incident and haven't seen any rise of any size since. Don't get me wrong, I was pleased but not counting on anything either. It was all about waiting until the October 2019 adjustment. So now we know why this is late. Sort of...
Where is my Adjustment??
Never thought I would ever be pining for something that was much more likely to be bad news than good but October 11th came... and went. It is now a week later. The adjustment is way overdue. Truth be told, I was expecting the worst. In fact, the very worst. Remember my stint from April to July; benign level 2 charging barely touching the upper 3rd of the pack?
Well, my multiple in town appointments and commitments were done. My calendar was clear and the weather was gorgeous, so I hit the road. Now, not as hard as I have in the past but still racked up dozens of QC sessions including my first EVER 11th temperature bar! IOW; the pack did not have a lot of rest on my days off.
So this morning, I updated the spreadsheets, started looking at my monthly and 1000 mile trend lines and noticed something.
As mentioned above, my pack lost most of its capacity in 5 sessions. But there was still 2.07 ahr lost in day to day action. This calculated out to roughly .12 to .15 ahr lost per month. But so far this month, I have lost .02 ahr. that is 3X less than the average. Now, I haven't done a lot of driving and only have 2 days exceeding 100 miles in a day but have 11 QC sessions.
So at this point, I am not sure I know what to think. Is it possible the BMS took over a year and a half to learn my driving habits and adjust the readings accordingly?
Soon, I started seeing others reporting similar results of either no change, a very small drop (explained by the fact that very few check their stats EVERY day like I do) or a rise in stats. So whatever the issue is, its systemic. Now whether Nissan programmed it purposefully that way or whether they even think its a problem is anyone's guess.
Either way, my projected 56.55% SOH at 100,000 miles has ballooned to 69% which means just missing a warranty exchange which would be a disaster but right now I am trending to be well above 80%...
So best I can say is "I guess we will see what January 2020 brings us"
