April/May 2020 Drive Report

It appears no one missed last month's report so I felt a reminder that you should be anxiously awaiting each month's report was appropriate. 😊

Since this report is covering 2 months, a report on the battery's 90 day adjustment is next and yes it happened pretty much right on schedule.  If you recall, the first adjustment was the largest ever  (2 cars!) so being a bit apprehensive was a bit of a concern despite multiple reports of  milder adjustments coming from all over the World.  This one started April 25 (the first one started January 25th and lasted 9 days) and ran 4 days.  I lost 1.29% SOH this time so hardly a good thing but at least it wasn't an extreme thing like the first one when I lost over 2½%.  Probably not a factor but in 2 of the 4 days, I DC'd and drove over 90 miles.

Either way, my current stats has me at ahr 167.90, SOH 95.18% with just over 8800 miles.  My mileage totals would have been much lower but had a unique opportunity to be part of a labor shift at work in order to address rapidly escalating needs caused by COVID 19.  This meant my normal 25 mile round trip commute went to 47 to 50 miles one way.  Yes, I was paid a bit more to do this but the real incentive was being paid 57 cents per mile from my home. 

I had only intended to do this for a few weeks just to see what it was like but after getting my first two reimbursement deposits, I quickly decided I was riding this cash cow into the ground! I mention this as justification for my driving over 3000 miles during the height of the stay at home phase.  I ended up doing 6 weeks at 4 days a week banking over $1300 in travel reimbursements.  All my charging during the first 3 weeks used my EVgo promo received when I picked up my E Plus.  EVgo sweetened the pot by dropping its lowest per minute rates 25% and removing the subscription requirement due to COVID.  This COVID  pricing was recently extended to June 30th.  I suspect that will be extended again.  The last 3 weeks, I only used EVgo on the last day of the work week, charging at home for the rest of the week. This was mostly done to gather info on best charge timer settings.

For the month of April, I drove 1668.2 miles averaging 3.93 miles/kwh using 400.54 kwh from EVgo and 6 kwh from home costing me an all time high for the Plus of $5.57 (8.44 cents/kwh)  In May I traveled 1354.2 miles averaging 4.11 miles/kwh using 118.57 kwh from EVgo and 236 kwh from home costing me $20.41.  (Guess that record didn't last long)

Neither month saw me using public AC charging. My main use is at Capital Mall in West Olympia when seeing a movie. Looks like that won't be happening any time soon... Hopefully Cinemark does not go under before then. Their movie club is a bargain.

Managing SOC

As mentioned, my long commutes enabled me to play with charge timers and I found the easiest way to control SOC was to set the timer so the car is still actively charging when you get up or are planning to leave.  Since I was normally up 90 minutes to 3 hours before my scheduled departure for work, I had that much leeway as far as how long I wanted to charge.  This meant not having to adjust my settings every day.  But even if adjustments were necessary, it quickly became a 10 second task after learning the navigation settings to the correct place.

Now I am still using the EVSE I got for my 2013 LEAF which did have a 6.6 KW AC charger but my panel was not up to the task. Living in an old house, my panel is a Zinsco which has since been banned for new construction or upgrades. This means getting breakers for the panel is all but out of the question.  Luckily, I  had an unused 30 amp breaker than had been used for a pump on the old septic system so I am restricted to 24 amp charging which is fine by me.  I have never been inconvenienced by this but then again, if you have followed this blog you would know I have done minimal home charging over the past 3½ years.

Well, that gravy train is all but gone. I have only a few bucks left on the EVgo promo, my NCTC expired in February so I am on my own. Either way, it took all of a few days to see that I charge about 10% per hour.  I say "about" because the LEAF SOC meter is not linear.

Now what makes sense is the meter on showing usable capacity and that would be great...but it doesn't. It has a hidden reserve that slowly grows as the SOC drops. When the SOC meter hits zero you have about 20 miles of range on the Plus so keep that in mind before you complain you didn't hit the EPA numbers.

With the Plus, the error is a non issue. Whether I charge to 60% or 65% is not important to me.  Its more than double (in some cases quadruple) the range I expect to need that day and its in the "good for battery" zone so all is good.

Decoding the Algorithm

Another thing I wanted to look into is why these 90 day adjustments are happening.  The 2018's all seemed to follow the exact same pattern. Numbers never rose. They either went down very slowly or stayed the same then after 90 days they would drop a chunk.  This went on for nearly everyone for 12 to 18 months then nearly everyone saw an adjustment that went up. There was also adjustments that stayed the same or simply were too small to notice (not everyone checks the LEAF Spy daily like I do)

Then the Plus came along and the 90 day adjustments are still there but this time there is a twist. Most are seeing small adjustments between ¾ to 1¼% but then we started seeing reports that people on their 2nd or 3rd adjustments saw numbers go up!  Remember the March 2020 Drive report?  I quoted a LEAFer in Phoenix who has gone double the miles I have and has half the degradation. But unlike me who has done 90% DC charging, he mostly does AC charging AND he always charges to full!

Now its one thing to state the obvious that Nissan is making progress towards a cell chemistry that doesn't need active cooling but to do it in Phoenix is way over the top!  Either way, I still do not recommend charging beyond what you need.  So if you need 200+ miles that day, charge to full!  But if you need 50 miles that day, I don't see any good reason to charge over 70-75%.

But maybe there is another reason for these adjustments? Could they be evaluations or predictions of how our pack will go? It isn't really possible for a pack to gain capacity so what other explanation is there for the increases?  What if our habits during one 90 day period were particularly bad so we got a very large drop but then the next 90 day period our habits were very good. Would that cause a change to the algorithm that created that very large drop so extreme that it results in an increase? 

Now I know this is pretty far out there but then again, I am in a unique position in that I am going from nearly all DC charging to nearly all AC charging.  Will this make a difference in my next adjustment? 

Breaking Down the Adjustments

As mentioned my first adjustment started Jan 25 or 2 months and a week after I picked up the car. This implies a build date "around" October 25, 2019 and 10/19 is the build date of record. Unfortunately, there were several other unusual events preceding the start of the adjustment including my 2nd full charge (the first was done by the dealership) for my Olympic Peninsula drive.

First Adjustment

First thing you will notice is nearly all my charging was DC @ 648.489 kwh.  Adding that it was winter this means I was charging the car every 2-4 days so my battery temps were generally low in the upper 40's to 50's most of the time.  Don't know if that matters but just putting it out there. 

Second Adjustment

My 2nd adjustment the high DC usage continues. During this adjustment I drove 3534.7 miles, adding 835.66 kwh of DC recording 875.1 kwh usage from the dash. So pretty much the same charging pattern as before.  This adjustment started during my 3rd week of labor share commuting. 

Currently I am now 50/50 on DC/AC charging since the 2nd adjustment. We shall see at the end of July if it made a difference. The results would be more valid if it was still Winter but I am planning a quarter of near 100% AC charging right after next January's adjustment so stay tuned. 

If you have any questions about the data presented, chime in thru the comments. If you are wondering, there is probably someone else wondering the same thing.