E Plus Charging Profile; Still Searching For RapidGate!

RapidGate/IceGate started with the 40 kwh pack.  This is when the charging profiles on a DC session changes based on the starting temperature of the battery pack.   Now this is significant because other packs from the Bolt, Tesla, etc. act differently adjusting charge rates upwards if the pack is cold initially.  Cold packs are limited in the current they can handle so need to heat up a bit before taking on the full current a station can hand out.  There is some thought out there that this is being unnecessarily overcautious especially if charge rate is 1.5 C or less.

History

The original LEAFs charged...well slowly even on a "quick" charger.  On a station supplying up to 125 amps, the knee (when current starts to drop) was generally in the mid 30's SOC.  Now this was pre LEAF  Spy so only had the dash to go by.  With the reserve, the knee was probably around 40% SOC give or take a few.

30 kwh

Nissan's first major capacity increase happened with the 2016 model year introducing the 30 kwh pack for the SL's and SV's (S trim received 30 kwh packs starting in October 2016) and apparently Nissan heard our complaints.  Now that the early and free days of DCFC charging was fading fast in the rearview mirror, the pay per minute issues made the slow charging a bigger issue to contend with.  My 2016 S 30 would charge at full speed past 80% SOC! This was a godsend because of my work demands and adhering to a schedule that had no wiggle room. Delays for slow charging simply wasn't going to work.  The ability to grab a 10-20 minute boost under a wide range of battery conditions (hot/cold, high SOC) with a decent amount of range really made EVs an attractive option in a job where I logged over 25,000 personal vehicle miles for work a year.

Although the 30 kwh was a good boost in range, it was still not nearly enough for any real charge management on a road trip. If you were lucky enough to be in an area that had DCFC's every 20-30 miles or so then it wasn't so bad but most of the country was not lucky, so more range was needed.

RapidGate/IceGate And 40 kwh packs

In 2018, Nissan released the 40 kwh pack for the 2018 model year. It wasn't the rumoured and highly anticipated 60 kwh TMS pack we were hoping for but again, a decent bump in range along with several new driver aids.  I hadn't planned on getting one but my hand was forced when my beloved (and undegraded) S30 was killed.

A quick perusal of the EV options quickly revealed that even without the HUGE incentives of the past, the LEAF with its higher price was still the best option for me so l jumped on it as soon as they hit the streets. I was one of the first S 40 customers Ray had!

But it took all of ONE workday for me to realize that the full charge past 80% SOC I was expecting was not to be.  Not even close really as I was lucky to see the knee squeak past 50% SOC.  Now it was February and the added range usually only meant needing one QC to cover me which means heat wasn't an issue,  I was IceGating and didn't know it.

Heat

Because of changing personal needs (and escalating gridlock!) I made the tough decision to take a rather large pay cut and change employers. This put me on a 4 day work week with a 25 mile round trip commute which meant MORE TIME FOR ROAD TRIPPING!

So well before the heat of Summer arrived, I experienced the full brunt of RapidGate.  A trip in April revealed that my pack charged best (highest SOC @ knee) when batt temps were in the 80'sº F at the start of the charge but as soon as the pack hit 90º, I no longer received the maximum current at the start of the charge.  As the pack heated up, the starting current continued to drop until I charged at North Bend EVGO starting temps 121º and had max rate of 61 amps (of 120ish) to start!  My 30 minute NCTC charge didn't even get me to half ! (45% SOC)  The charging rate was so slow, the batt temps went DOWN during the session to 118º (yeah, it was a bit nippy OAT in mid 40's)

RapidGate Mitigated

Now Nissan knew about RapidGate rather quickly and since their main market focus for the new LEAF was Europe (Yeah, we now have assigned seats in the nosebleed section) they released a software update in May 2018 to alleviate the ramp down. It helped but it was an EU update ONLY!!

But it was still Spring in America. The heat of Summer hadn't happened so the outcry in the US was barely a whimper.  In fact; most claimed their LEAF didn't have RapidGate.  Then July hit.

Olympia's year round mild climate insured that only multiple fast charges revealed any RapidGate effects. But elsewhere, it wasn't the case. Soon, social media was flooded by people not seeing more than 25 KW on their FIRST QC of the day.  Ambient heat along with sometimes aggressive driving was more than enough to heat up the pack.   We immediately started complaining about the issues to Nissan but our voice wasn't really heard until Jennifer Sensiba started a petition to simply allow us to get the software update that ALREADY EXISTED!!

I was almost ready to give up hope which was rare for me ( ok, maybe I wasn't!) when in mid July 2019 A YEAR LATER!! Aaron McAfee, the resident LEAF tech guru of the Pacific Northwest, notified me that a RapidGate SW update was now available and when did I want to come in and get it done?   I immediately went on social media to tell everyone the great news and ....

Well, no one believed me.  We had several supposedly connected people claim they contacted Nissan who told them no such plans to allow an update THAT ALREADY EXISTED!! to be issued to North America. So my announcement went virtually unnoticed until 5 days later when Nissan announced that it was now available to us.  Try to be helpful I do and what do I get?? Anyway...

Because of concerts, focus groups and birthdays, it took a few weeks to get the update but on August 1, 2019 the update was done that included a battery plate bonding recall. So two updates at once! and barely an hour in the shop. If you need LEAF work, go to Aaron at Puyallup Nissan. He is worth the drive!  It was another week before I had a chance to test the update and I did see a definite improvement ranging from 30 to 60ish% faster.  The hotter the pack, the greater the speed increase.

IceGate

As the days grew shorter,  I started noticing a reduction in charge gained during my 30 minute EVGO sessions. It wasn't much but since I was VERY consistent with the 30 kwh pack,  the variance was worth looking into so I started looking at my charging logs (I track EVERY QC on LEAF Spy) and started noticing cold weather affected the charge.

Unlike Tesla and Chevy, the LEAF starts at max current even when the pack is cold, at least within the parameters of the Pacific Northwest "cold."   So I decided I needed to test the charging when the pack was cold and this meant waiting for a cold snap to get a full range of results.

Chevy Bolt charging on a cold WA morning. After 7 minutes, they have only gotten

to 22 KW. (TMS must not be awake yet???) Later in the charge, they did manage to

get to 35 KW. 

It didn't take long for my suspicions to be confirmed. IceGate was real.  When my pack temps hit the 40'sº F, the knee was dropping in to the 40's as well, SOC that is.  So we were now getting it from both sides now!   FYI; I went thru the charging logs on my S 30 and surprise surprise. It didn't have IceGate either. I did manage to find one instance where the knee happened at 77% but starting batt temps were in the mid 50's so not all that cold to begin with.  Most others including ones that started over 120º F, still had the knee over 80% SOC!

62 kwh E Plus

Unlike the bump from 30 kwh to 40 kwh, the E Plus pack not only increased capacity but also increased their module count.  This allowed more of a "spreading out" of the charge received by the pack making the individual stress on a cell much lower.  So it made sense that higher power would be fine and Nissan did upgrade the DC to 100 KW.   Now based on the knee, SOC limitations, etc. You won't see 100 KW but reportedly 80 KW would happen.  And when we get a 100 KW Chademo, I will test that theory out!

NCTC Gone

Nissan ended the NCTC promo the first week of July this past summer as planned.  It provided 2 years free DC charging with Blink, Webasto and EVGO. This meant I was soon faced with the decision of what vendor I would be charging with when my promo ends February 15th, 2020.  With the charging speed issues above behind me now, I needed to understand the parameters of how the E Plus charged and what was the best circumstances to alleviate RapidGate/IceGate, etc.

Heat Gain and Retention

It didn't take long for me to realize that keeping my E Plus pack warm wasn't going to be very easy. I did nearly a full 30 minute charge on EVGO the other day, gained nearly 23 kwh and pack barely hit 70º. Battery temps at charge start in upper 40's, knee just over 65%

120 amp knee; 65.24%  batt temps start 

47.4/47.8/47.8

IceGate On The E Plus

So, its simply not the time of year for RapidGate testing. The pack isn't retaining heat like the 40 nor does it gain heat simply while driving or regenning. Guessing its a combination of more cells and better chemistry.  The E Plus does have a slight bump upwards on the E Pedal regen profile  seeing up to 189 amps but B mode remains the same as the 40.  Remember, I am seeing 200 amps from EA DC charging sessions so even with the higher regen profile of E Pedal, its still not an extreme hit to the pack. 

The Test

I purposely overcharged (AKA as charging to 70% SOC 😁 ) to allow extra time for the pack to cool off between charge sessions. Although we did have a few colder days, car is in garage at home so only exposed while at work and was able to get two charges in with pack in the mid 40's º F. I also wanted to see how much speed the EA DC had to offer. Its well known that the 50 KW chademo which generally has a limit of 125 amps (which is exactly where my 40 kwh charged at) but EVers were seeing over 150 amps so I had to see what I would get and I was not disappointed. 

SSSSSWHEAT!!  You probably have to click and scroll to see the details here

but 200 amps is a game changer for roadtripper! 

 The plan was to preheat the pack by high speed driving, lots of heat, and a QC.   So off to Centralia I went.  I charged there 20 mins heating the pack to 65.7/66.9/64.9º.  I then sprinted to the Lacey EA at 70+ (Hitting 80 mph frequently in the South County area) with heat blasting, etc. and more than 30 miles later, I was at 65.1/67.5/69.1 º.  This was not what I was expecting.  One temperature went up (guessing it was more equalizing after the Centralia QC) while one barely changed but one WENT DOWN!! 

WTF?? It wasn't that cold so heat didn't work hard but I figured the speed would more than make up the difference. Temps were in the upper 40's (in Centralia) to low 50's (In Lacey) I then realized getting a full spectrum of temps to test would be tougher than I thought.  My target was a charge in the mid 40's, 50's, 60's, 70's, and 80's.  But I was faced with a 5 day work week (not used to that kind of demand on my time!) and much more driving and charging than I was ready for.  So the testing is somewhat incomplete but the trend seems rather clear. 

With a 4% increase in SOC at the charging knee (120-125 amps) from the mid 40's to the mid 60's, I am quite giddy to think that the ideal charging temperature in the mid 80's could yield near 75% SOC!  This would be well beyond my dream expectations.  If you followed the IceGate link above, you would see that my 40 kwh at temps in the 40's had a knee below 50%. From the blog

Dec 5; start; Batt temps; 48.7/47.6/45.8  SOC;32.2 Max Amps; 123.901
Dec 5; knee; Batt temps; 61.7/61.3/58.3 SOC; 47.3

An improvement from 47.3% to over 65% is HUGE!! I have to say, I am pleased. This is real pack progress. 

Stay Tuned! 

My initial experience with the E Plus doesn't even begin to illustrate the massive changes from the 40 kwh to this car.  Still unknown is how the car will respond when the mercury hits triple figures but early indications are very good.  Guessing the pack has to be a lot warmer though. But, I think Nissan is finally realizing what Tesla knew from Day One. Without a big pack, there is simply no wiggle room.  Even if the knee doesn't change at higher temperatures, this car will be a godsend to many including me. 65% SOC is still over 2 hours of freeway.   I can no longer drive for hours at a time probably from simply getting old. I am still investigating seat cushion options (Have two, they help but didn't really fix anything...) and this all started in my 40 kwh LEAF where it took well over a year for me to notice I was no longer comfortable so I have to think its not the car. 

With the end of NCTC, I will need to start an analysis on which charging station provider to use. With subscription charges required to get the best price, the days of "too many cards" is long gone. EVGO is more expensive but more prevalent in my area. EA is cheaper and charges faster but less convenient with its one shared Chademo plug and still  sparse in the area but growing fast.  Webasto is rumored to be getting out of the public charging business which is greatly disappointing so their $20 unlimited plan is likely nearing its swan song.  So being able to maximize my dollar at the charging station is paramount to EV affordability.   I will admit, its been so long since I had to budget for gas, even a few bucks seems excessive for just driving if you know what I mean. 😏  So charging without the knee is basically the goal. With per minute billing, the faster you get it, the cheaper it is per mile. 

30 min EVGO DC NCTC charge, no knee. 22.77 kwh received. 

Now, I know detractors will ride the TMS bandwagon until the wheels fall off but just a reminder; Elon Musk said the ultimate goal is a pack that doesn't need TMS. There was a rumor, still unsubstantiated, that the E Plus pack received a circulation fan so that is one thing I will be trying to confirm.  Remember the Bolt charging in the cold of a Washington State morning? He was in Covington, WA.  So I decided to see how my LEAF handled the cold so not wanting to heat of the pack, I took mine to the Lacey EA "on the same day" Ummm,  TMS'ers... You might want to see this. 😊