All-electric road trip from Orange County to San Francisco's east bay
For Memorial Day weekend of 2013, we planned to take our family of four in a new Model S on a road trip from
our home in Orange County
to visit grandma's house in San Francisco's east bay.
This would become our first long-distance road trip using an all-electric car.
It did require a little bit of planning and preparation. First, I needed to figure out
how much time we needed to spend at each Tesla Supercharger, and whether I needed all three
(Tejon Ranch, Harris Ranch, and Gilroy) or just two.
Along the way, my curiosity led me to explicitly test the behavior of the Hawthorne Supercharger,
starting with a depleted Model S battery and
measuring its effect on it every five minutes.
Then I fit a formula to that data so that I could describe that behavior mathematically.
That resulted in a Supercharger Table that
became very useful for predicting how much recharge time we really needed, and also
showed that a one-hour+ lunch stop in Harris Ranch was more than enough to make the
last leg of the trip.
So here's a little picture log of the trip in my Model S.
Model S OC-SF Road Trip
The cargo space in the Model S is amazingly large and comparable in volume to that of the typical minivan.
We did fill much of its space, but even so we easily had room for another suitcase
|Tejon Ranch Supercharger - Northbound
As we traveled, I logged the time, odometer, and range remaining for every event of interest.
Range/Distance ratio: 1.18
|1:04 pm||Departed Home||255|
|3:28 pm||Arrived Tejon||97|
Conditions: Hills and Heavy Traffic
Being the beginning of Memorial Day weekend, traffic was against us,
which definitely slowed us down and reduced our energy efficiency.
Using the Supercharger at Tejon was quite simple. Plug it in, then don't worry about it.
So we focused on the kids, getting frozen yogurt, then playing around for a while,
then going to get drinks and snacks at Starbucks.
Ours was one of four Tesla's charging there.
It turns out all the extra prancing around by the kids and getting them
fed and settled took over a half-hour longer than the charging time
needed by the car, so we ended up with a nearly full battery,
more than originally intended.
|Harris Ranch Supercharger - Northbound
Range/Distance ratio: 1.23
|4:32 pm||Departed Tejon||260|
|6:14 pm||Arrived Harris||117|
Driving to Harris Ranch was simple enough.
Again we could plug in and go into the restaurant.
We called ahead for
a reservation just in case it was too busy.
We saw two other Tesla's charge.
Like before, our kids were being antsy, refusing to choose what to eat,
wanting time to play.
The technology behaved exactly as predicted, but it was the
kids again who had us wait an extra half hour.
Range/Distance ratio: 1.32
|7:17 pm||Continued Charging||264|
|7:49 pm||Departed Harris||271|
|10:25 pm||Arrived SF east bay||39|
Conditions: Hills, Strong Winds, and Traffic
This was the leg that was the greatest unknown to me, skipping the
Gilroy Supercharger and proceeding with the final 173-mile leg of today's trip.
From the sound of the wind it seemed we had 20-30 mph gusts
pushing the car around. This region (the 580 highway east of Livermore)
has wind farms, so this area is well known for
such weather conditions.
This extra air resistance increased our energy consumption, and knowing it was our longest leg,
I reduced speed, which turned out to be unnecessary because we
ended up with virtually the same range remaining as predicted.
|Charging at Grandma's
Prior to the trip, I researched and determined that the
dryer outlet plug was the standard 30 A three-prong type common
across the US, but the location required a cable to snake 40 feet from the garage.
So I purchased a 30-foot NEMA 14-50 6-gauge extension cord (the Tesla-supplied cable is 20 feet long)
and the parts needed to build an adapter for a NEMA 14-50 plug to the dryer outlet plus
a grounding wire to the plumbing.
At home I assembled the adapter and tested out the whole system first.
At grandma's house, I told the Model S to limit its consumption to 27 A, allowing a 10% safety margin.
[Note: Tesla Motors Club members have pointed out that I should've limited it to 24 A. A 20% margin is considered necessary for continuous loads like charging EVs.]
Charging worked perfectly at a speed of about 14 miles of range per hour.
My kids played with their cousins, and I gave them, as
these kids' first ride in a Model S, a little thrill ride
around town. They enjoyed it, yelling like on a roller coaster.
When we stopped
we all thought it was funny to let them
hop and tumble
in the trunk like it was a little playground.
Yes, of course, we did not drive around like this...
|Harris Ranch Supercharger - Southbound
Range/Distance ratio: 1.16
|9:48 am||Departed SFEB||266|
|12:22 pm||Arrived Harris||63|
We casually took our time to leave grandma's house, but easily made it
to Harris Ranch at lunchtime. This southbound leg felt like we had a
tailwind and the wind noise was much less, and,
given what I learned from the northbound leg, we had more than enough range remaining,
so I increased speed of this leg.
At the Harris Ranch, another Model S had a large dog on a doggie bed in the back trunk.
Like before, however, one child couldn't choose
what he wanted to eat, then after food arrived demanded the food
he rejected the last time we were here. All told this
added a half hour beyond the car's need for energy.
|Tejon Ranch Supercharger - Southbound
Range/Distance ratio: 1.17
|1:32 pm||Continued Charge||263|
|2:10 pm||Departed Harris||270|
|3:51 pm||Arrived Tejon||134|
Conditions: Light traffic
The drive to Tejon was quite pleasant. Upon arrival we
took another opportunity to have frozen yogurt. Meanwhile a few other Tesla's arrived
being admired by other travelers.
the kids loved running around and playing, again extending our
time by almost an extra hour.
Range/Distance ratio: 1.13
|5:05 pm||Depart Tejon||265|
|7:08 pm||Arrived Home||119|
Conditions: Traffic and Downhill
The drive home was hampered by traffic, as expected for
Memorial Day, but I knew we couldn't run out of range,
so I pushed it.
In short, the technology worked exactly as we hoped.
The experience of driving the Model S is so much more relaxing than a typical gas car because it does not have the extra engine and transmission noise, but
especially because this car leaves behind
the low-frequency rumble and roar that shakes one's innards.
The Model S is an amazing road-trip car.
Like the trip north, going south it was the little humans aged 2 and 6 (throwing temper tantrums, taking extra naps, refusing to choose what to eat, running around, etc.) who extended our stay at each stop, well beyond the car's need for charge.
Consumption going south was considerably less than each segment going north.
It's as if we had a tailwind pushing us south.
Actually the SF to Harris segment was definitely less windy, from the sound in the car, than going north.
The range consumed and average speed for each segment:
|Leg||Range Consumed||Average Speed
||Leg||Range Consumed ||Average Speed |
OC - Tejon|| 158 miles || 56 mph
||Tejon - OC|| 146 miles || 64 mph|
Tejon - Harris||143 miles || 68 mph
||Harris - Tejon||136 miles || 69 mph|
Harris - SFEB|| 232 miles || 67 mph
||SFEB - Harris|| 203 miles || 73 mph|
Note our average southbound speed, for each driving segment, was higher than our northbound speed.
The data from the trip north told me we had enough margin to drive faster, which I applied to the trip south.
Translating this into energy, the conversion would be 85 kWh / 270 mi of range = 315 Wh/mi.
At 12 cents per kWh, that means the cost of "fuel" was $20.41 to go north and $18.33 to drive south.
Cut that down by a third if the Tesla Superchargers' energy are considered "free".
Fueling my previous (gas) car on such a trip would easily be five times the price.
To think a year earlier no production electric car could make either family trip in a day.*
(Or maybe not at all?) I think that's an accomplishment.
After this trip, I've also taken this Model S on
several trips each using only one charge.
Dean E. Dauger holds a Ph. D. in physics from UCLA, where his group
created the first Mac cluster in 1998. Dr. Dauger is the award-winning
author in multiple American Institute of Physics' Software Contests and
co-authored the original, award-winning Kai's Power Tools
image-processing package for Adobe Photoshop.
After founding his company,
Dauger Research, Inc., its debut product,
Pooch, derived from Dr. Dauger's experience using clusters for his
physics research, was soon awarded as "most innovative" by IEEE Cluster
and continues to revolutionize parallel computing and clusters worldwide
with its patented technology.
*While the Tesla Roadster was known to make this trek, it can't carry my family
and ended production in January 2012.
Non-Tesla production electric cars can't make the distance between charging stations available then, or
don't have the capacity, or couldn't charge fast enough to finish in a day.