Thursday, February 6, 2014

Seattle to Disneyland--Is it possible in a Nissan LEAF?

When I was in fifth grade, I watched, for the first time, National Lampoon's Vacation.  It was a fantastically inappropriate movie for a 10-year-old to watch, and it was AMAZING!  Clark Griswold became my closet hero, and I longed to one day take my future family on a cross-country trip to Walley World.

Obviously, Walley World was a semi-fictionalized dream land.  As I got older, though, and now with kids of my own, taking my family on a cross country trip from our home in the Seattle area to the Happiest Place on Earth became an obsession.  And after successfully driving a Nissan LEAF on the BC2BC All-Electric Rally from Canada to Mexico, and back, getting my family to Disneyland in our EV was becoming a possibility.

While the 1,200 mile trip to Disneyland is now clearly attainable in a LEAF, doing so with my two children and lovely wife, however, will require more CHAdeMO quick charging infrastructure in California for the possible to become reality.

When examining the logistics of the trip, I first researched the state of CHAdeMO infrastructure in Northern California between Yreka and Sacramento and in California's Central Valley, between Modesto and Bakersfield.

After driving the 560 miles of these two parts of California in a LEAF in the summer of 2013, I started referring to these regions as the "EV Badlands" of California. With no quick charging available for a LEAF on 70% of the drive in California, the folks at Disneyland are not likely to tap into the EV tourism market of LEAF owners in Washington, or Oregon for that matter.

To my surprise, Nissan looks to be tackling the infrastructure issue itself with some recent CHAdeMO installations in the EV Badlands. Chico, Visalia, and Bakersfield now have quick charging available for LEAF drivers!  If Nissan would install CHAdeMO units at its dealerships in Redding, Modesto, Merced, and Fresno, the dream of Disneyland would no longer be Fantasyland.

To then complete the minimum quick charging needs, the state government of California needs to find a way to supplement Nissan's CHAdeMO deployment with installations in Yreka, Mt Shasta, and Lakehead in the north.  Additionally, there will need to be infrastructure in Grapevine, Lebec, and Santa Clarita for travel between the San Joaquin Valley and Los Angeles County in the south.

The politicians in Olympia and Salem figured out how to support CHAdeMO infrastructure in the Northwest. Surely, the elected officials in Sacramento can figure out how to deploy six CHAdeMO charging stations in a state with more than 38 million residents.

With a hypothetical CHAdeMO infrastructure completed, the next hurdle was to figure out how to deal with the inevitable heating of the LEAF's battery pack during uninterrupted driving and charging cycles. The trip would likely require about 25 quick charging events to get from our house in Lake Stevens, WA to Disneyland.

Traveling at 70mph in a LEAF = Very High Pack Temps!

The above graph shows the peaks and valleys of battery pack temperatures during continuous highway travel and quick charging.  On this particular trip, I drove the LEAF frequently at or above 70mph. Each of the 17 sessions displays the average velocity (mph) for the driving prior to a quick charge, pack heating on the drive and while charging, and the duration of the quick charge session.

(Note that the 45 degree temperature drop between the fifth and sixth quick charging session was due to an eight hour overnight stop.)

The pack temperatures displayed in this graph are only representative of the T1 sensor on the LEAF battery pack.  This part of the battery pack is by far the most susceptible to out-of-control heating, as the other sensors of the battery pack show that different battery cells can be more than 25% cooler.  The packaging of the LEAF's battery cells clearly created a weakest link, and the area around the T1 sensor is it.

It was tough to initially pinpoint what had the greatest impact on rising pack temps, so I utilized Excel's correlational formulas to extract more precise values.  The greatest correlation, not surprisingly, was between the battery pack temps upon arrival at a quick charger and the temps after the charge completed.  Duh!

*To see the complete correlational data analysis, view the Google Drive spreadsheet here.

*To view the complete LEAF Spy data file for either one of these trips, please email me at:  coramsc at gmail dot com.

All other factors:  driving speed, total time quick charging, and travel time between quick charging sessions all seemed have an impact. However, the statistical correlational values just did not provide me a clear variable that needed to be controlled to predictably reduce battery pack heating.  Except for the variable of quick charging itself!

Busy Night on the West Coast Green Highway!
With this initial analysis completed, I decided to perform another road test.  This time, I would set the cruise control at 55mph and do continuous quick charging and driving all night long.  My hypothesis was that the lower driving speed, and the subsequent slower battery discharge and longer time (an hour) in between quick charge events, would result in stabilized battery pack temperatures.

We own two Nissan LEAFs, a 2012 and a 2013. I wanted to provide a worst-case scenario, so I used our 2012 which only has about 89% battery capacity as compared to our 2013's wonderfully-healthy 100% capacity pack. Additionally, the heater was never turned off (also an energy drain when compared to newer LEAFs).

The loop consisted of quick charging in Burlington, WA, traveling at 55mph to Bellingham, WA, and returning at a 55mph pace back to Burlington.  Six quick charge sessions were completed, with 308 miles covered in 9 hours and 35 minutes of driving.  At the same pace, continuous charging/driving from Seattle to Disneyland will take a little more than 38 hours...130 hours quicker than my 2013 trip!

55mph to Keep Pack Temperatures In Check

While the 117 degree temps are a bit scary for the LEAF driver, the bigger picture is more palatable. Only one sensor was showing that part of the pack was hot. Upon leaving the quick charging station after the sixth session, the LEAF's dashboard display showed 8 (out of 12) battery temperature bars. Within a few minutes of driving, the dashboard displayed a very reasonable 7 temp bars.

There is not an experienced long-distance LEAF driver out there who would be uncomfortable with the battery pack at 8 temperature bars.

The dream of Disneyland is almost a reality. And just like Clark Griswold's family in National Lampoon's Vacation, I will defy my family's wishes of flying to our vacation destination. Instead, we're going to load up the family truckster with kids and Kool-Aid and hit the open road!..twenty-first century style.

Destination: Disneyland.

1 comment:

  1. Having a good car to travel around is really important. I traveled with my family to WDW Orlando with our Audi Q3. We were in Omni Hotel at Championsgate which we booked with Thank god we had a car with us. The hotel was quite luxurious for the money but it was a little away from the city so we had to travel around with the car.