As even the most casual reader of my website will have noticed,
my wife Becky and
I are committed to living sustainably. This all began in 2001 when
Becky purchased the original
hybrid. This amazing vehicle
was the highest mpg production vehicle ever made - it originally got
65MPG, but that diminished when ethanol was added to gasoline here in
the US to around 53MPG. It is also rated
(Ultra Low Emission Vehicle). The Insight is designated as a "mild hybrid", since it
operates in gasoline powered mode all the time while the battery
electric system augments its small three cylinder 1 Liter engine.
Later, I purchased a used 2006 Ford Escape Hybrid, this vehicle was also the highest gas mileage vehicle in its class, and it is also rated ULEV and PZEV. The Escape hybrid drive is much more like the Prius in that it can drive in electric only mode for 2 to 3 miles. I came to call the EV mode "stealth mode" because the vehicle becomes so quiet. I realized that driving in stealth mode was good practice for driving an electric vehicle effectively. Both my wife and I have been quite competitive about learning to optimize our the performance in both vehicles.
When I first heard about the Chevy Volt back in 2009, it was just a concept car announced by GM as being considered for production. I was immediately intrigued by their unique solution to the electric car range anxiety issue. Since we live in rural Maine, a fully electric vehicle did not strike us as particularly practical since we need the option of being able to travel extended distances. The Volt lets us have our cake and eat it too, the on-board 1.4 L 4 cylinder gas engine (GM calls it a "range extender") powers a 50kW generator that can power the vehicle at 40MPG so long as you have gas in the tank. The generator activates transparently as the battery runs down and is almost silent, only becoming noticeable on hills and rapid acceleration when it ramps up the RPMs to around 4000 to provide extra juice to the electric motor and battery. This completely eliminates EV range anxiety and allows us to take long trips without thinking too much about it - although we have become hyper-aware of gas mode usage.
In 2011 I entered a contest sponsored by GM and WIRED magazine. Contestants were required to produce a video up to 2 min. long demonstrating how they were using technology to live sustainably. I was one of the four people who won the contest. You can see the winning videos here. Winners were flown to Detroit with a friend or spouse in August 2010 and wined and dined for 4 days at GM's expense.
We toured the GM Hammtrak manufacturing plant where we got to see the some of the first Volts being made. We also toured the battery design center and met the chief designers of the Volt, and finally were able to test drive a pre-production model on their test track at their Milford proving grounds. Needless to say it was an exhilarating trip. Winners all were invited to write their own review of the Volt for the Wired Autopia blog, and I also wrote a detailed review for Home Power magazine, and also reviews for local newspapers.
One of the contestants, Patrick Wang had already pre-ordered his Volt, and acquired serial number 10. He has his own very detailed website called mychevyvolt.com and forum that readers of my website will enjoy visiting since it also has a comprehensive forum for Volt owners. GM also has their own site and Volt forum.
My wife and I had considered the Volt to be out of our price range at nearly $40,000. However in August 2010 my father passed away and left me a substantial sum of money. The day that I received my inheritance, my wife and I drove over to Goodwin Chevrolet and ordered our vehicle. They found one that fit our needs at another dealer less than 100 miles away, and we drove our Volt off the lot a few days later. With a 50% down payment we qualified for a 0% interest loan for the remainder making it quite affordable. Here we are shaking hands with Evan, our salesman. We were the second people to purchase a Volt from Goodwin, and are probably the fifth Volt owner in the state of Maine as of May 2012.
Since we have a 5.8kW solar power system in place, most of the power required to charge the Volt will be free solar energy in the summer, hence vanity plate for the Volt: SUN PWRD. In the middle of the solar day our solar array can produce around 4.4 kW, and we generate around 30-40 kWh per day on good sunny summer days - up to 75% less in the winter. To fully recharge the Volt battery requires around 13 kWh, so charging on a sunny day provides free, carbon neutral power for the vehicle. We drive the Volt in electric mode about 75-80% of the time and in the gas generator "range extender" mode at 35-40MPG for the remaining 20-25%.
a geek one of the things I like to do is measure and quantify
information about the sustainable things that I embrace. Elsewhere on
my side you will see real-time statistics about our
domestic water heating systems. With that in mind I
acquired a used, reconditioned kilowatt hour meter for the
Voltec charging station. I installed the meter
and charging station myself on the side of my workshop, along with an
Electric Vehicle Charging Station sign. I will be
taking readings from the meter and the Volt odometer every Sunday, see
the chart of data below.
current info about our Volt in my blog.
How does it work?
This short GM promotional video explains it quite simply
I decided to compare the vehicles I have at hand with the Volt to see if I could confirm my perception that the Volt is quieter. So I used my sound level meter (pictured at left in the Volt) to get readings. For the driving tests I drove at 55MPH on the same stretch of road with all windows closed, climate control off and sound system off and the meter was held in a similar position for every test. Here's what I learned, the readings are in decibels (dBA), keep in mind that the dB scale is logarithmic:
This clearly demonstrates that the Volt is much quieter inside than other vehicles - even the similarly aerodynamic Insight. This correlates with the actual driving perception - it's quiet as a tomb. All you hear is the tire sound. In the other vehicles there is the engine and transmission sound to contend with. I recently smoked past a slow vehicle on a 2 lane blacktop using SPORT MODE and it was almost spooky not to hear the "vroom" of acceleration.
Cost to operate
The Volt is definitely much less expensive to operate than a regular gas vehicle. The overall maintenance costs are lower since the oil and brakes rarely need changing.
Based on our first 12 months of ownership since May 2012 with over 16000 miles on the clock we have saved approximately $1050 on gas costs at an average of $3.50/gallon compared to an equivalent 30MPG vehicle. We used an average of 311.32 kWH/month to drive 1293.20 miles, costing about $42.30/month. We spent around $533 on gas for the Volt for the year, while a 30MPG vehicle would have required $1614 in fuel (details on my blog).
Below is a comparison chart showing our calculated monthly cost compared to a regular 30MPG gas vehicle assuming an average gas cost of $3.50/gallon. The chart is derived from our actual miles driven in the Volt each week. In Maine we are currently pay 13.6 cents/kWh which is above the US average of 9.83 cents. This chart does not factor in the free electricity we get from our solar power system for the sake of a fair comparison, but in the summer months our electric bill drops below $15.00/month meaning that we are charging the Volt for free from the sun!
I will be updating these charts every Sunday:
Range per charge
The EPA rating for the 2013 Volt's electric range is 38 which is about average. Our 2012 model is rated for about 35 miles and our actual range varies from a low of about 27 miles in the dead of winter to a high of 47 miles in the spring and fall. The reason it is so low in the winter is because the battery is using a great deal of energy to maintain a minimum battery temperature. (If the battery gets too cold, or too hot it will be damaged). Similarly, in the summer air-conditioning can use a significant amount of energy which reduces mileage range in the summer. Here in Maine we have three months where temperatures rarely get above freezing and often dip below zero Fahrenheit, in more temperate climates the actual range would be significantly higher in winter. For more information, see the fueleconomy.gov page about the Volt.
Of course this does not mean that that is the farthest you can drive on any given day in EV mode, in fact we have driven over 100 miles in EV mode by charging multiple times. Our 240 V charging station can put a full charge on the vehicle in 4.5 hours (at 3700 Watts). Our record to date is 508.27 miles driven without using gas and 1964.37 miles per tank of gas. We got this information from the VoltStats page (see the bottom of this webpage for details).
To put charging energy in context, a full charge uses the equivalent amount of energy as if you left 2 large 1500 W room heaters running for 4.3 hours. This adds up to 13 kWh, and if you are paying $.10/kWh this means it costs you $1.30 to top up the Volt.
The Volt's dashboard - while sexy does not provide some basic information like HOW MUCH energy is recovered from regenerative barking, or used in normal driving. Our Insight and Escape both had gauges to show Charge/Assist energy flow:
This information, along with a detailed battery state of charge are very useful in learning efficient driving and planning energy usage. The Volt dash does have a green "leaf" ball (left) that moves up and down to advise you when you are driving inefficiently, but I find this too abstract. It also has a graphic animation showing energy flow, but this does not convey quantity, and it is slow to respond to changing driving conditions. These features are "cute" and help explain how a Volt works to someone unfamiliar with the technology, but advanced hybrid/electric drivers like me need more info. So I bought the Dash DAQ from Drew Technologies and mounted above the dash like a gps device. This is a professional racing driver gauge that is user configurable.
My preferred custom screen shown above displays things I am most interested in. I configured the tach to turn blue when the engine generator is running and it is interesting to watch since engine speed does not track vehicle speed directly. Also the engine is so quiet that you really can't hear it running most of the time, so this helps me to see what it is doing. For example it stops when you slow or stop the vehicle, and re-starts sometime after you get going depending on how low the battery is. Unlike a hybrid, the engine/generator shuts off on the freeway if you have built up sufficient charge (above 22% state of charge typically) from regen during a downhill run.
I also set up the battery current gauge to turn green when regen energy is going back into the battery, and red if the motor is drawing over 100 Amps (35kW) - peak power is around 112kW!). These gauges look cool and are both fascinating and informative. I have other screens that show more details such as engine coolant temperature, battery temperature and brake torque etc.
Update: October 2012
I just learned that the 2013 Volt has a new display mode just below the speedometer that shows energy flow in graphical format. This tiny display is about 1" high and so it is not very high resolution, but it does go a long way toward informing the driver about the quantities of energy flowing to from the battery and engine generator. I hope that this gauge will be offered as a software update for the 2012 models.
One word: amazing! The first thing you notice is the quiet, you can talk to each other in a whisper on the freeway because the only sound you hear is the tires on the road. At speeds below 14 mph the vehicle is essentially silent and you have to be careful in parking lots. Then there is the raw power available thanks to an electric motor that can peak at over 100 kW (yes, that's One. Hundred. Thousand. Watts!). If you punch the vehicle into SPORT MODE the accelerator becomes hypersensitive and you find yourself thrown back in your seat if you punch it to the floor. The 0 to 60 spec is 8.5 seconds which compares favorably with many contemporary stock sport cars. This power is available immediately with no delay while a gas engine winds up or a transmission is slipping. To be blunt this vehicle is so thrilling to drive that my pulse still races every time I drive it (I am writing this after one year of experience with the Volt). It corners like it is glued to the road due to the low center of gravity - there's a 400+ pound battery bank between the seats and behind the rear seats.
We always drive it with the shifter in the "L" position - this is not a gear since there is no gearbox in the Volt - it is a mode that optimizes the regenerative braking feature. This allows for one pedal driving since when you lift your foot off the accelerator the vehicle slows so dramatically (while recharging the battery) that the only time you need to touch the brake pedal is a few feet before coming to a stop. We leave the vehicle in L mode even on the freeway since it can recover a lot of energy on the downhill slopes, this is particularly noticeable in cruise control. The benefit to this mode is increased range.
The seats both front and rear are quite comfortable for long drives, this is one of the most comfortable vehicles I have ever owned. Plus there are a number of amenities that you expect with an premium contemporary vehicle, such as the ability to plug in your iPhone or iPod to the USB Jack in the armrest and then access your music from the center console. And of course a Bluetooth hands-free connection for smart phones is built-in along with all of the amenities of OnStar including turn by turn navigation and emergency assistance. The climate control system is excellent, and we tend to leave it in "auto" mode so that it handles everything including humidity, defrosting, and cabin temperature. It is generally a bad idea to open the windows because the aerodynamics of the vehicle creates a buffeting and fluttering sound at speeds above 45 mph, although I occasionally drop the drivers window a few inches on the freeway every now and then without ill effects.
There is plenty of cargo space in the Volt. I have transported 6 8ft 1X12 boards INSIDE the vehicle - they go all the way down to the front passenger floor area. I have also carried 2 large 66″ x 37.5″ 240 Watt solar panels inside - barely. The rear cargo area is large enough to carry anything we have encountered in normal every day use. And when the rear seats are down there is even more room for large items.
One of the features my wife and I enjoy using the most is the remote start feature from the vehicle's key fob. This allows us to pre-warm, or pre-cool the vehicle from up to 100 feet away while it is still plugged into the charging station. The Volt uses the last setting of the climate control system, which we leave at around 76°F. After 10 minutes the climate control will shut off and the vehicle will shut down again but that is plenty of time to bring it up to temperature inside even on frigid days when it is well below freezing. And all this from "shore power" which does not drain the battery (if it is below about 20F the engine will run until the coolant reached about 150F).
We can also access the vehicle systems via the OnStar app on our iPhone, or also from the web. This allows us to check things like tire pressure, fuel level and battery charge, and we can also remotely lock, unlock and start the vehicle. Monthly status reports are emailed to us that worn of any issues from low tire pressure to pending maintenance like upcoming oil changes.
5.9kW solar power system, we can use it to provide most
of the energy needed to charge the Volt in the summer months, and a
smaller percentage in the winter. Take a look at the chart
from June 1, 2012 below from my
energy monitor to see how a full 3.5 hour (about 13kW) charge from our 240V
Voltec charging station
came mostly from solar:
As Kermit the frog says: "It's good to be green"
Since I recorded that chart above on June 1, 2012 we added 3 - 230Watt solar panels to our array (690 Watts in full sun). Below is a net energy chart recorded on July 8, that shows the Volt being charged after driving about 35 miles starting from a full charge using about 10kWh. Energy below the zero line is being exported to the grid and "banked", above the line is being imported from the grid. This shows that our solar array now can provide all the power needed to charge our Volt in the middle of the summer.
I have installed a real-time energy monitor that records the power being sent from our Voltec charging station to the Volt. It is currently drawing Watts. Charging power averages about 3500 Watts for 3.5 to 4 hours and drops to near zero when the charge cycle has completed - I think the charger consumes some standby power to keep the 2 green LEDs lit etc.
In the winter the Volt draws power occasionally to keep the battery warm when temperatures drop below 15F. Based on data logged from my charging station, it uses around 1500 to 2000 Watts for periods of a few minutes to over 10 minutes as needed. Here is a chart comparing charging power to outside temperature for 24 Hours in January 2012:
That first spike of 2500 Watts was when we pre-warmed the vehicle remotely for 10 minutes prior to driving it. The sustained energy draw represents a full battery charge after that trip and the small spikes represent power drawn for up to 10 minutes at between 1200 and 2400Watts for thermal management. Not a great deal of energy compared to battery charging, but it does point out the value of leaving the Volt connected to the charger in temperature extremes. If the battery gets too cold the Volt will not let you drive until the gas generator has run long enough to warm the battery up to its safe operating temperature.
Below are real-time charts showing the real-time power usage of our Voltec Charging station. You can mouse over the charts below to see detailed readings. I have placed the temperature charts below so you can see the correlation of power used for thermal management of the battery in very cold (below 10F) and hot (above 100F) temperatures.
Below is a chart showing how many kWh we are using weekly from our 240V Voltec charging station and total miles driven that week. This does not factor in the "free" charging we get when we plug into 120 Volt outlets at our destinations such as friend's houses and church etc. On longer out of state trips we have also used public charging stations occasionally, as yet there are no public stations in Maine (April 2013).
I will be updating the chart every Sunday afternoon, but it seems clear that since we typically use most of a full battery charge each day at about 13kWh that our weekly usage will run around 60-90kWh.
Note that when the miles/week bumps up close to the kWh/week - that is when we have driven extensively in gas "Range Extender" mode, such as on a long trip, so many of the miles driven were powered by gas at about 40MPG.
In Maine we pay about 13 cents/kWh, so a week of charging costs us around $11.00. So we are seeing a monthly cost to charge the Volt of about $47 - assuming a full charge every day, without factoring in our free solar energy. An equivalent 25MPG vehicle using gas at $3.50/gal. would cost $170/month. Assuming a rough average of 1200 miles driven per month our electric cost-to-operate is around 6 cents/mile. Compare this with the cost to operate a 25MPG vehicle with gas at $3.50/gallon = 14 cents/mile. As gas prices rise, the EV advantage gets better, and of course most of our electricity is free from our solar array so our actual cost is near zero in the summer months.
Volt Stats! page
A guy named Mike Rosack has built a web site called Volt Stats! that allows Volt users to track the EV and gas MPG performance of their vehicles, and compare their stats with others. Volt Stats interfaces with the OnStar web service used by the iPhone/Android RemoteLink apps to collect data about the performance of Volts driving in the real world. The graph and charts below show data from our vehicle and I will be updating them weekly on Sunday afternoons. (click on the graphics for more details).
Monthly percentage of miles driven in electric mode
for the last 12 months:
and miles driven per month in electric mode:
This chart clearly demonstrates how the Volt is affected by temperature. It uses a lot
of energy to heat the interior cabin and battery in winter, and here in Maine
temperatures remain below freezing for over 2 months in the winter.
Read more current info about our Volt in my blog