Reader Rides: Electric Car DC Quick Charging Works Perfectly, But We Really Need More Charging Stations

I’ve been driving my 2012 Toyota Rav4 EV electric car for two and a half years now. Over 35,000 miles my EV has met my daily driving needs and provided the range to drive well over 100 miles to camp grounds, state parks, Bay Area cities, Napa Valley and more, where I can then use charging stations to charge up for the trip home.

I can drive to most regions within this green circle on a single charge.

I can drive to most regions within this green circle on a single charge.

To illustrate this point, on the left is a map of California centered on my town, with a 100 mile radius indicated in green overlaid on the map.  I’ve driven to many locations within the green circle on a single charge.  Driving to higher altitudes, for example to Lake Tahoe, would of course require an extra charge because it takes more energy to climb mountains.

During a typical work week I drive about 50 miles a day commuting to and from work and running errands, and log about one hour of driving time each day.  Every other day I plug in my EV for about 5 hours and charge the battery pack on my Rav4 EV to about 80% capacity.  I either charge at work while I’m in my office, or at home in my garage while I’m sleeping.

The Rav4 EV has a ‘Level 2’ charge port that accepts up to 240 volts and 40 amps, or nearly 10 kilowatts of power.  Most charging stations provide 6 or 7 kW of power, resulting in about 20 miles of range being added to the battery for each hour of charging.  This works fine for my daily commute to work during the week, for errands, trips to the grocery market, and weekend excursions to some of our favorite places in our region of California.

But there are times when having the ability to quickly charge an EV is a great benefit.  That’s why Nissan, BMW, Kia, Volkswagen, GM, Mitsubishi (and of course Tesla) make battery powered electric cars that have a DC rapid charging port.  For the non-Tesla EVs these are called DC quick charge (DCQC), or DC fast charge (DCFC) ports.

During the week I drive about 50 miles a day, and usually charge my EV to 80% capacity every other day. The red line shows the rate at which battery State of Charge increases during charging.

During the week I drive about 50 miles a day, and usually charge my EV to 80% capacity every other day. The red line shows the rate at which battery State of Charge increases during charging.

Toyota did not provide the Rav4 EV with a DCQC port.  But 6 weeks ago I purchased a CHAdeMO DC quick charge port, called JdeMO and made especially for the Rav4 EV by Quick Charge Power.  I’ve since put the JdeMO port to use a number of times and it has changed the calculus for how I drive my EV. (For more information about the benefits and costs of DC rapid charging, see this Transport Evolved post.)

Here’s an example.  Last week I visited a research group I work with in Merced, CA.  The trip was just over 130 miles one way.  I stopped once for 30 minutes on the way down, and once for 30 minutes on the trip home to recharge on DCQC stations.  I drove along CA Route 99 which has decent coverage with DCQC charging stations.

I have a MyCarma data logger that records the distance and time of each trip, and battery state of charge at the beginning and end of each trip.  I’ve plotted the data collected during my trip to Merced in a chart to demonstrate how DCQC facilitates travel – sourced from domestic power – for cleaner, efficient, longer distance driving.  For a comparison, I’ve plotted how long my charging stops would have been to reach the same state of charge if I had instead used Level 2 charging stations.

Comparing the total driving and charging time using DCQC versus Level 2.

Comparing the total driving and charging time using DCQC versus Level 2.

Panel A in the figure above shows the total driving and charging time for my trip using DCQC stations.  Panel B shows the route I took, indicated by the blue line.  The location of DCQC charging stations is marked with orange icons (data from Plugshare.com).  Panel C shows how long my driving and charging time would have been for the same trip if I had used Level 2 charging stations.

As you can see in Panel A, I started with a full battery.  It was a chilly 48 degrees with light rain, lots of morning traffic, and I had warm coffee and the radio to keep me company.  I opted to bypass all the initial DCQC stations, and after driving 118 miles arrived at the Atwater DCQC with 29% battery capacity remaining (about 10 kWh)  – more than enough to reach my destination.  But, because of the heavy traffic it took me over 2½ hours to drive that distance.  And even though I was only 15 miles from Merced, after drinking all that coffee I really needed to stop so I could go.

Many DCFC stations are conveniently located near stores and places to eat.

Many DCFC stations are conveniently located near stores and places to eat.

I plugged in the CHAdeMO cord, and while charging for 30 minutes (the grey area on the charts), I stretched my legs and found a coffee shop where I could get a bite to eat and reload my travel mug with fresh coffee.

That 30 minute charge stop brought my battery state of charge up to 76%, giving me over 100 miles of range.  That was enough to visit my colleagues in Merced, and then drive to the Salida DCQC station on my way home, with plenty of extra to spare.

The charge stop on the way home got me up to 83% SOC, giving me enough driving range to drive the 80 miles home and arrive with about 10 kWh remaining in the battery pack.  The whole trip had been 265 miles and it was just plain simple.

I could have made the same trip using Level 2 charging.  The nrg DCQC station in Atwater also has Level 2 charging, and there is a Chargepoint Level 2 station in Merced.  But, at a rate of 20 miles of range per hour charging, I would have needed a total of 7½ hours of charging, instead of just 60 minutes, to reach the same state of charge I got with DC rapid charging.

Level 2 charging will serve the bulk of my charging needs for my day to day routine.  But being able to rapidly charge my car when needed is a huge improvement.  Increasing the number of DCQC stations will undoubtedly increase the number of people and businesses using electric cars for travel.  The State of California needs to fully get on board with DCQC and complete the West Coast Electric Highway, and open charging corridors along heavily traveled routes.  The ability to branch out, to drive further and quickly reach new destinations – powered by cleaner, domestically produced energy – has opened new horizons for me.  If you haven’t driven an electric car yet, take one for a test drive and I’ll see you on the Electric Highway.

Disclaimer: The author has no financial ties or connections with companies and organizations mentioned in this article.

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