My Bittersweet Chevy Volt Moment

By · February 26, 2011

My first trip to the gas station in two months. The efficiency tally is 980 electric miles at 2.43 miles per/kWh, and 250 miles at 32.5 mpg.

February 22 marked two months since the December 2010 delivery of my Chevy Volt , number 24 off the assembly line. (See photos from the event.) Once this marvelous vehicle had reached 1,291 miles on the odometer—1,212 miles since I got it—I experienced what car owners all over the world endure far more often: for the first time, I had to visit a gas station. I found this a bittersweet experience.

Ron's Volt Efficiency />

Bitter because I finally had to do it—my dashboard informed me that gasoline range was down to 34 miles—and helping to fund the oil oligarchy in the process, though only to the tune of $30.61 or $184 a year. Sweet because I used so little gasoline, though I had it available to extend my electric range whenever necessary.

It took 7.7 gallons to fill the tank, an average of 157 mpg (plus electricity)—actually higher, since the tank was not full when I got the car! Because GM used a lot of gasoline testing my car in the 79 miles before I got it, my dashboard indicates “only” 137 lifetime mpg.

In charge-sustaining mode—when the battery is depleted—I have usually been getting 30 - 35 mpg. If we call it 32.5 mpg, it means I drove 250 miles on gasoline and 980 miles or 80% of the time on electricity. Though I haven't yet taken any long-distance trips, I have driven extensively around the San Francisco Bay area. My ChargePoint Driver Portal shows 401 kWh of electricity consumption. I used another 2 kWh charging elsewhere. My electric efficiency from the wall was therefore 411 watt-hours per mile, 2.43 mi/kWh, or 82 mpge (as the EPA calculates it). The overall efficiency was 63 MPGe.

I'm not complaining, but both gasoline and electric mileage are much lower than expected. I'm not sure why, but I’m hoping these figures will improve as the car gets loosened up and the weather gets warmer and drier. I have neither been hypermiling nor acting like a race-car driver. In fact, I've been driving similar to what used to get me 40 mpg in my Prius and 80-100+ mpg when driving it as a plug-in conversion.

Ron's Volt Efficiency />

I do know three things that have contributed to high electric consumption. First, with Bay Area temperatures between 30-70 degrees F, I've made moderate use of (electric) cabin heat and the Volt’s wonderful heated seats. Second, to minimize gasoline use, I’ve charged almost every time I’ve arrived back at home, even after just a few miles of driving. I’m sure such top-off charges are less efficient than full charges, because low charge rate and charge balancing inefficiencies occur mostly near end-of-charge. Third, I’ve seen noticeably higher fuel consumption during the frequent rain we've been having. This is hard to track as 80% of my miles have been electric, and the Volt gives its driver no electric power or energy information—a major oversight in my opinion.

We are initiating a new CalCars.org open-source project to equip my Volt with digital instrumentation that plugs into the vehicle’s service port to log, learn, and disseminate important unseen details about this groundbreaking and very complex vehicle’s operation, capabilities, and efficiencies in actual consumer hands. If you can provide any technology, information, or financing for this effort, please email info - at- calcars.org.

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