Nissan Engineering Team Visit Dec. 3rd: Recap

[gascant]

As much as I believe Kadota-san's explanation of the difficulty in determining true or estimated SOC, I will also say that in 4 months of owning the SOC meter, I have never seen it jump suddenly (more than the 0.3 or 0.4 % that it changes during normal vehicle operation). So, they might be applying some sort of smoothing function to the measurements. And if it did jump around, you might also expect it to jump up occasionally. I have only seen the SOC increase when I've been in regen mode going downhill.

[astrorob]

it seems that even their estimate can cause "mysterious" jumps in the SoC and they want to shield the user from that confusion.

in fact, now that i think about it, this is probably why the existing SoC meter has such coarse granularity. they must have chosen this as a natural mechanism to damp out the SoC variations from their estimate. in fact the one Japanese engineer who did ask a question of the group asked something along the lines of "but what do you think about the SoC variation?" and in the context of what Kadota-san said later, he must have been asking "do you really want to see an SoC gauge that bounces all over the place?"

[evnow]

overall i think he was trying to convey the idea that there's no "true" SoC and any direct report of the SoC to the user will be just as much an estimate as the DTE currently is. of course reporting the SoC would remove the extra component of the recent driving history from the computation and perhaps be a little more clear to the driver.

I think the most important DTE is the one presented at the start of the trip i.e. when Leaf knows the SOC more accurately. The efforts to get better DTE should be focused on that. That DTE can then be adjusted to take care of actual conditions compared to what was used at the beginning (for eg. estimate was based on 40 mph, but it was actually 50 mph).

Perfection shouldn't become the enemy of good. We need Nissan (and other OEMs) to continuously improve DTE algorithms. It is a critical part of getting more acceptance for EVs until battery technology improve enough to make range not a big issue.

[astrorob]

overall i think he was trying to convey the idea that there's no "true" SoC and any direct report of the SoC to the user will be just as much an estimate as the DTE currently is. of course reporting the SoC would remove the extra component of the recent driving history from the computation and perhaps be a little more clear to the driver.

I think the most important DTE is the one presented at the start of the trip i.e. when Leaf knows the SOC more accurately. The efforts to get better DTE should be focused on that. That DTE can then be adjusted to take care of actual conditions compared to what was used at the beginning (for eg. estimate was based on 40 mph, but it was actually 50 mph).

Perfection shouldn't become the enemy of good. We need Nissan (and other OEMs) to continuously improve DTE algorithms. It is a critical part of getting more acceptance for EVs until battery technology improve enough to make range not a big issue.

yes, i would agree with that.

perhaps rather than trying to nail an exact number they could give a best-case and worst-case estimate. i think they are always battling between confusing the ordinary user with a load of information and simplifying the information too much. they seem to be painfully aware that they have to present the information in such a way that it can be understood by the average person, and not an engineer EV enthusiast. my personal opinion is that they are going to try very hard to come in on the conservative side of any estimate. the worst thing that could happen is that they tell you 20 miles are left and there's only 5 in real life. their lawyers probably worry about what could come of consistently overestimating the range...

[gascant]

perhaps rather than trying to nail an exact number they could give a best-case and worst-case estimate. i think they are always battling between confusing the ordinary user with a load of information and simplifying the information too much. they seem to be painfully aware that they have to present the information in such a way that it can be understood by the average person, and not an engineer EV enthusiast. my personal opinion is that they are going to try very hard to come in on the conservative side of any estimate. the worst thing that could happen is that they tell you 20 miles are left and there's only 5 in real life. their lawyers probably worry about what could come of consistently overestimating the range...

Yes, exactly! That's kind of what we said up front in our SOC presentation and why we suggested that they make it user-selectable. Keep it simple (default) for those that want it uncomplicated, but provide the option for those that know how to use it. We also asked them to provide the OBD II codes so that aftermarket SOC meters could be made while they work on their strategy.

[TonyWilliams]

Here are my raw notes:

Mark Perry:

10,000 LEAFs sold in the USA by about Jan 3, 2012.
20,000 worldwide

Tennessee will have the largest battery plant in the world. Changes to the LEAF are likely to occur with the Tennesse plant becoming operational (2013 model year, 6.6kW charger, new colors, etc)

4 new EVs coming (or three more, actually, I think). Utility, sporty, something else.

1.5 million EVs produced by Renault/Nissan by 2015.

The Nissan team was here in the USA for official acceptance of a new EV at their proving grounds in Arizona.

Hidetoshi Kadota - chief engineer for LEAF and the Nissan Quick Charger.
30 years total with Nissan
10 years chassis
20 years EV development

Today is LEAF birthday.

Range: USA 100 miles LA4 cycle. 200km Japan, 175km Europe.

Car2house project, called PCS, expected March 2012.

Double fuse protection from lightning, the one currently in the car, and the one in the PCS. Showed 15kV lightening shock test video.

700mm water test video, same as petrol car.

LEAF- Car of the Year, Japan. He got aate night call for congratulations and genuinely seemed happy to have beat his competition.

16 people representing Nissan who introduced themselves,
most from Japan, then UK and USA.

Rolf Schreiber from Google gave us a talk. They now have 13 LEAFs, and numerous other EVs there and coming. The intent is to have 5% of the parking lot have EVSEs.

There are currently have 34 company car EVSEs, each with J1772 L2, NEMA 14-50R for legacy EVs, and 120v USA household plug. In addition, they have 90 employee spots.

Mark Perry: Nissan fast charger is UL listed.
Phil Sadow: GM Volt EVSE is not UL listed.

84 LEAFs in parking lot, numerous in remote lot for over 100 total.

Mark Perry: -30C, lithium batteries stop working. Cold weather package is only real change to 2012 model for cold weather state sales. They are working on a heat pump / resistant heater combo, since heat pumps are not more efficient below 32F/0C.

Chief engineer: they monitor the 96 cell pairs: DTE = SOC x km/kWh

USA Quality Assurance guy: yes, the legal mumbo jumbo you signed says only 1 quick charge per day, but that was for worst case summer in Phoenix at high speed (load).

QC will automatically protect the battery in high heat by slowing the charge rate.

ANY TIME TEMPERATURE GAUGE IS BELOW RED ZONE (NORMAL RANGE), QC IS OK. Protections are related to temp.

[linkim]

Thanks Tony for taking the notes summarizing the meeting yesterday. You may have a permanent job at our meetings, if you attend.

When I mentioned to a Nissan visitor that someone is flying in from San Diego, one from Orange County, and one driving from Washington, he was surprised at the interest in the meeting. I told him there are some very passionate LEAF owners out here. I think we demonstrated that to Nissan at the meeting.

Am now working on an encore, sort of, but at a much lower level. I don't want gascant to have a heart attack before the holiday season.

Kim

[Boomer23]

4 new EVs coming (or three more, actually, I think). Utility, sporty, something else.



The Nissan team was here in the USA for official acceptance of a new EV at their proving grounds in Arizona.

So you're sayin'..... there's going to be a Nissan sports EV. I'll take that as a definite, then.

And the acceptance of a new EV, what could that be? The Infiniti version of the LEAF?

[Boomer23]

BTW, Your personal Chargepoint card will not operate on Google campus. Hopefully our hosts have a card with access.

Update;
One final footnote on the charging. I will make a sweep through all the L2 charger areas about 10 min before the meeting to make sure that all the chargers are activated. Howard, would you mind sending a last minute reminder to folks that have asked for charging to make sure they leave their charge port door open even if they can't activate the charger? I'll make sure they get plugged in. I don't want to have anyone stressing out because they can't get the charger to work.

KeiJidosha, doing his usual quiet, unsung helpful job. Did you drive the MiniE up there?

[abasile]

I would like to express my appreciation to all who made this meeting possible, and to those who are now reporting on it, for the benefit of the rest of us. Nissan's level of commitment to electric vehicles is truly impressive.

As much as I believe Kadota-san's explanation of the difficulty in determining true or estimated SOC, I will also say that in 4 months of owning the SOC meter, I have never seen it jump suddenly (more than the 0.3 or 0.4 % that it changes during normal vehicle operation). So, they might be applying some sort of smoothing function to the measurements. And if it did jump around, you might also expect it to jump up occasionally. I have only seen the SOC increase when I've been in regen mode going downhill.

I have repeatedly seen the SOC *decrease* during regenerative braking, immediately following a long mountain ascent. Driving up CA-330 on my way home, I climb almost 5000 feet in about 14 miles (see http://www.mynissanleaf.com/viewtopic.p ... 60#p143277" onclick="window.open(this.href);return false;), then descend about 150 feet in elevation. Almost invariably, I have seen my SOC drop during regen braking on that small descent. Sometimes this even translates into losing a charge bar. After transitioning from continuously discharging the battery to charging, perhaps the car is able to refine/improve its estimate of OCV.