Results matching “road trip”

For owners who may be new or unfamiliar with the Tesla Roadster, I'll run through the basic information needed to preserve this rare and special vehicle.

The most obvious concern is properly maintaining the battery pack. If the Roadster is left unattended and without power for weeks or months, the battery back will slowly discharge until the pack is fully depleted. If this happens, the battery pack may be ruined. Even if plugged in, if power is interrupted by a popped breaker, extended outage, service disconnection, etc., permanent damage to the battery pack can occur.

Also of concern is temperature. The Roadster should not be left unplugged in extreme temperatures. If the battery pack gets hot, it should be plugged in so it can cool. Consult the owners manual for more information.

Charging

Level 1 In the United States and Canada, the Roadster can be charged at 120V with a simple cord sold as the MC-120. It just connects the car to power with no EVSE logic and the car assumes a 15A circuit suitable for charging at 12A. At this power level, the car can't run the full cooling system and in fact uses a lot of the power just to run the coolant pump. This means a slow rate of charge, and in fact in hot weather, may use all of the power just trying to cool the battery pack. In comfortable weather, not too hot and not too cold, and no rush to get charged, this can be an effective way to charge. Some owners used Level 1 exclusively. Since the coolant pump tends to run continuously, even after charging is complete, there may be a corresponding reducing in the lifetime of the coolant pump.

Level 2 charging means connecting to 240V single-phase power using an EVSE that communicates the maximum current draw allowed for the circuit. It uses the same communication protocol as standard J-1772 charging stations. Having more power means the battery pack can be better thermally managed, which can make quite a bit of noise when the fans, compressor and pumps are all going full tilt. The maximum charge rate of the Roadster is 240V/70A. Unless we were in a hurry on a road trip, we generally charged at 240V/32A which yields good energy efficiency and may be nicer to the battery.

The Roadster can charge from a standard J-1772 station with an appropriate adapter. Tesla sold one for a while and there's an aftermarket adapter.

Charge Modes

The Roadster has four charge modes, used for different purposes.

Standard Mode limits charging to the middle 80% of the battery pack, not letting the charge level get too high and warning the driver, and even shutting the car down, before getting critically low. This is the mode used for daily charging of a Roadster that's driven locally with some regularity.

Range Mode opens up the full charging range, allowing a higher state of charge and enables driving down to a lower start of charge. Range mode also limits power from the pack, and thus reducing maximum acceleration in the name of extending range. Occasional range mode charging didn't seem to have a negative effect on our battery pack, but charging frequently to the top of range mode may accelerate the loss of battery capacity. When we owned a Roadster, we'd do a full range mode charge at the start of long road trip, then switch over to standard mode for driving.

Performance Mode uses the full charging range, allows the battery to get warmer while charging, and allows maximum power (full acceleration). This is appropriate for driving on a track, but probably accelerates loss of battery pack capacity if used often.

Storage Mode displays the state of charge like Standard Mode, but will let the state of charge drop to around 30% then will maintain that level of charge. This is the best mode to use when the Roadster won't be driven for weeks or months. The car must be plugged in to maintain the health of the battery pack. The disadvantage of Storage Mode is that if the power supply is interrupted, it will start discharging from around 30%, so it will get into trouble sooner than if left in Standard mode. That's probably more of a concern if it's in long term storage and ignored vs. being kept for the winter in your garage where you'll notice of the power goes out or the breaker gets tripped.

An example charge screen:

The drawing below shows how to interpret the state of charge in the two main charge modes. Range values are for the original 53 kWh battery pack when new.

Vehicle Log

The Roaster maintains a detailed internal log which can be downloaded via the USB port in the console. Although the format of the logs isn't documented by Tesla, various owners have been able to decode and extra a great deal of data. The log file has two sections: a long term section that has basic info and a more detailed section of recent driving and charging. See the page on the VMSParser I created for more information.

Remote Monitoring

The Roadster did not have support for remote monitoring, not at all for the 2008 (v1.5) Roadster and nothing driver-accessbile for the 2009 and later (v2) Roadster.

There is an aftermarket system availble, the Open Vehicle Monitoring System or OVMS. OVMS allows for remote monitoring of charging, GPS tracking, custom charge settings, and viewing battery metrics. In addition to allowing manual remote monitoring, it can also send low-battery alerts and unexpected motion alerts if the car moves not under its own power.

More Resources

There are a number of other entries on the blog detailing our adventures with the Roadster, plus another collection of longer Roadster articles of practical and historical interest.

The Tesla Motors Club forum is the best community resource around, although its focus has natually shifted to the newer Tesla vehicles.

Charging an electric vehicle is pretty easy: just like my cell phone, I plug it in when I get home and it's fully charged in the morning. It doesn't matter how long it takes because I'm not waiting for it to finish; the car just charges up and waits for me.

Electric vehicles are awesome for local driving. Driving within the single-charge range of an electric vehicle is more fun, more convenient, and cheaper than driving a gas car. Many people are drawn to the idea that they can abandon gas stations, fuel at home, drive 130 miles for the cost of a gallon of gas and all in a car that has a quiet ride and instant, smooth acceleration that can't be matched by a gas car.

Electric vehicle drivers are excited to see the first DC Quick Charge stations coming online. Oregon and Washington have done their part to power up the West Coast Electric Highway allowing electric vehicle drivers to travel I-5 from the Canadian border to the Oregon-California border and take advantage of stations that can charge a Nissan LEAF or Mitsubishi iMiEV from empty to 80% in about half an hour. This greatly increases the usable range of electric vehicles for longer trips and also provides a safety net for rare situations when drivers unexpectedly need more than their normal overnight charge.

Unfortunately, there's a problem that is causing a lot of confusion that can result in a driver getting less charge than needed. Even though the stations are working properly, drivers may think something went wrong because of a user interface issue.

The above is the screen from an AeroVironment DC Quick Charge station in Tumwater, WA, as shown while charging our Nissan LEAF in June. The screen shows the driver two pieces of information: the amount of energy delivered to the car and a charge percent.

The problem is the displayed charge percent: it is not the car's state of charge (SOC) and should not be treated as such by a driver to decide when to end the charge.

It's pretty well known that it's difficult to determine the exact SOC of a car's battery. Even the best estimate of the battery's SOC may be off by a few percent. That's not what's going on here. The SOC value reported to the station is completely artificial and differs significantly from the car's estimate of the true SOC.

In addition to showing the invalid SOC value to the driver, Blink quick charge stations also require the user to choose a station-controlled charge limit. This has two big problems. First, the LEAF wants to control the charge and will stop the charge at either 80% or near 100% based on the battery state at the start of the charge, so even if you choose 100% on the station the LEAF will terminate the charge at 80% if the car was at 50% or less when the charge started. Second, the Blink station doesn't know the real state of charge and therefore cannot know when to stop charging at the point it says it will.

Here's an example. I recently used the Blink quick charge station at Harvard Market in Seattle, WA. I arrived with just over a half charge remaining, which means the LEAF will allow me to do a full quick charge up to near full capacity. After plugging in the car, the screen on the Blink station gave me a choice of charge levels, defaulting to 80%, which was the highest level shown. I had to press a "more options" button to be able to choose a 100% charge. The graph below shows data collected from the resulting 52-minute charge, comparing the car's actual SOC with the SOC shown on the station's screen.

As you can see, not only is the reported SOC higher than the actual SOC, the reported SOC rises more quickly, increasing the gap as the charge progresses. Throughout the entire charge, the SOC shown on the station consistently overstates the actual charge level and the problem gets worse later in the charge period. As the car gets to about 80% actual SOC, the reported SOC jumps up to plateau near 100% and just sits there for the remainder of the charge, even though the car is far from fully charged.

Had I left the default 80% setting, the charge would have stopped when the reported SOC hit 80%, but the car was really only at 73% at that time. A requested 90% charge would have stopped around 80% actual.

Any driver who sees this behavior and doesn't know that the charge percent value on the station is not the SOC would see it jump up to 97%, perhaps watch it sit there for a few minutes, and likely decide that it would be a waste of time to spend any longer waiting for that last 3%. If the driver ends the charge at that point, the car will be missing perhaps 10% of the potential charge. If that last 10% is needed to finish the journey, this could result in a very unhappy EV driver.

It's not clear where this value comes from, but displaying this invalid SOC on the quick charge stations has created user interface problem with unfortunate consequences for LEAF owners, and perhaps iMiEV owners as well.

So to any EV driver using a CHAdeMO quick charge station that shows an SOC percentage:

1. Ignore what the station shows. Put a sticky over it if you have to. Only look at the car's representation of the SOC.

2. If the station offers you different charge levels, choose 100% charge so that you get the car's best available charge level. If you want to stop the charge early for some reason, do it based on the SOC shown by the car.

I'll contact the quick charge station manufacturers to make sure they are aware of this problem. In the meantime, please help spread the word so EV drivers can get the maximum benefit from these highly valued stations.

For charts of two AeroVironment quick charge sessions, see Cathy Saxton's report. More tips for using quick charge stations are available on our Avoiding Quick Charging Pitfalls page.

On Saturday, June 16, 2012, a dozen electric vehicles made the inaugural drive along US Highway 2 over the 4,061-foot summit at Stevens Pass utilizing the newly-installed quick charge stations. Most of these vehicles recorded data for driving and charging; this blog is a summary and analysis of that data.

Cars charging at the DCQC and Level 2 stations in Skykomish, WA.

We have analyzed this data as well as measurements from other driving and have created pages with information on planning an EV road trip, including guidelines for predicting energy use based on drive conditions and tips for avoiding quick charging pitfalls.

Thanks to Ron Johnston-Rodriguez for all his work getting electric vehicle charging stations installed along US 2 and organizing this event.

Route

This event marked the official opening of DC quick charge (DCQC) stations in Sultan, Skykomish, Leavenworth, and Wenatchee, WA. It was also a test of the spacing between stations. Tom had helped with the US 2 electrification process by collecting data for driving this route in our Tesla Roadster in December, 2010, so we had good information on the energy use required for each segment.

With a carefully-orchestrated schedule from Ron, each vehicle was assigned a charging period at each station. This added a unique constraint, as vehicles would not necessarily have sufficient time for a full charge at the DCQC stations. We provided suggestions for a target charge level when departing each location and the expected energy required to comfortably reach the next station. The most demanding segment was the one over Stevens Pass; our guidance included a recommended state-of-charge level at the summit so drivers would know whether they should stop for Level 2 charging at Stevens Pass ski resort.

We got nifty SWAG from Leavenworth and Wenatchee!

Cars

We have data from 8 Nissan LEAFs, 1 Mitsubishi iMiEV, and 1 Tesla Roadster.

The DCQC spacing worked great for the LEAFs.

The iMiEV was able to make the drive with additional charging for the segment over the pass (charging Level 2 at Stevens Pass in both directions and Level 1 at Nason Creek for the westbound trip).

The Roadster can't use DCQC stations, but with its longer range didn't need much extra energy use. Tom was able to "opportunity charge" at Level 2 while we charged our LEAF and participated in the ribbon-cutting ceremonies.

Data

For those interested in all the gory details, the data and analysis are in this spreadsheet (XLS, 214k).

Drivers recorded information on time, distance, energy, temperature, and driving conditions. The details are in the individual EV# sheets. There are summary sheets for driving and charging that compare the data for multiple vehicles.

The iMiEV (EV1 in the spreadsheet) used an amount of energy similar to the LEAFs.

There were three LEAFs with after-market state-of-charge (SOC) meters that enable more precise monitoring of battery state than the factory instrumentation. These meters show the SOC as a percentage, and also in a unit called a "gid," which represents 80 Wh of energy in the battery. The gid values fell nicely in the range of values based on the LEAF's more coarse SOC bars.

We drove our LEAF (EV4) and Roadster (EV4b) together so that we could compare energy use for the same driving conditions. They turned out to be very similar; there is a summary sheet showing the data for both cars together.

Thanks to everyone who collected and shared data: Patrick, Phil, Lee, Jeff & Mary Lynne, Matt & Laura, Bruce, George, and Mike & Kimm.

EV drivers at the US2 DCQC inaugural ceremony in Wenatchee, WA.

Photo by Jessie Lin, WSDOT. Used by permission.

Quick Charging

DCQC stations made it practical to make this trip (and the return) in a single day. We learned several things about the stations with all the data collected by drivers during this event.

One of the most enlightening was confirmation of an observation during our prior DCQC experience: the station-reported SOC is not a useful indication of the car's charge.

When using a DCQC from under 50% to get to 80%, the LEAF's charge rate averaged 400-500 Wh/minute. When charging from over 50% to "full," the charge rate averaged about 200 Wh/minute.

The charging overhead (energy from the station that didn't make it into the battery) was 10-18%.

More details on DCQC are on our page with tips for avoiding quick charging pitfalls.

Driving

For each drive segment, these are the minimum and maximum kWh (and corresponding gids and bars) used between the DCQC stations. The energy use will vary based on speed and weather conditions.

Trip	miles	kWh	gids	bars
Eastbound
Sultan to Skykomish	26.4	7.20 - 8.24	90 - 103	4.5 - 5.2
Skykomish to Leavenworth	51.0	12.24 - 14.88	153 - 186	7.7 - 9.3
Leavenworth to Wenatchee	20.5	2.40 - 2.48	30 - 31	1.5 - 1.6
Westbound
Wenatchee to Leavenworth	22.3	5.60 - 5.84	70 - 73	3.5 - 3.7
Leavenworth to Skykomish	51.0	12.48 - 13.60	156 - 170	7.8 - 8.5
Skykomish to Sultan	26.5	4.80 - 7.04	60 - 88	3.0 - 4.4

Conclusions

The spacing of the DCQC stations along US 2 over Stevens Pass works well for LEAF drivers. Level 2 charging at the pass is either helpful or mandatory for iMiEV drivers, depending on the driving conditions.

We believe that an SOC meter is a valuable tool when making a trip like this, especially when pushing the range limits of the car. Because we'd projected our energy use for each segment and had a meter providing a higher resolution SOC reading, we were able to minimize the amount of time that we spent charging — including successfully skipping one station — and return home with a comfortable buffer.

Cathy and I took an 1,823-mile electric vehicle road trip to attend the Plug In America board meeting in Berkeley, CA, on June 23rd, 2012. Ever since we took delivery of our Tesla Roadster in June of 2009, I've wanted to take it on a long road trip just to have the experience. Over the past three years, the challenge of making the drive from Seattle to California has been greatly reduced. When Rich Kaethler took delivery of his Roadster in San Carlos, CA, and drove it back to Seattle in August of 2009, and Chad Schwitters made his long trek from Seattle to San Diego and back in April of 2010, these were pioneering efforts. Now we have full speed (240V/70A) Tesla charging along I-5 from British Columbia to southern California, which makes it possible to do the Seattle-to-San Francisco drive electrically in just a couple of days.

Hi, this is Cathy; I'm guest-blogging on Tom's page, and he's playing editor this time!

We recently needed to drive approximately 80 miles (one way) to get to clearer skies for viewing the Venus transit. That provided a great opportunity to try out DC quick charging (DCQC) with our LEAF.

We charged up to full in Bellevue using Level 2 charging, drove to the Tumwater DCQC station, charged back to full while we watched the transit, and returned home to Sammamish.

Data Collection

We have one of Gary Gidding's SOC Meters. It shows a state-of-charge (SOC) percent, which it calculates from a raw energy unit reported on the car's CAN bus. The meter can be set to show the raw energy unit, which the LEAF community has dubbed a "gid." It is reasonably well established that a gid represents 80 watt-hours (Wh). Gids are divided by 281 to approximate an SOC %.

Note that the pack kWh is not something that can be directly measured. The car determines this value through sophisticated measurements and calculations, which result in periodic adjustments that are seen as "jumps" in the gids.

Charging

We arrived in Tumwater with 2 bars, or more precisely 61 gids, which translates to 4.88 kWh, or 21.7%.

Since we were under 50%, our (first) DC quick charge brought us to 80%. The car charged for approximately 26:40 minutes, at which point it was showing 226 gids (18.08 kWh, 80.4%). The station reported having provided 14.36 kWh, and the car showed a net gain of 13.20 kWh.

The graph below shows the status each minute during charging. The lower blue bar shows the energy in the car's pack at the beginning of the time interval. The upper red bar shows how much energy was supplied by the station during the time interval. You can see that the total energy (existing + added) closely matches the pack kWh at the beginning of the next time period. (We only logged the station-reported kWh for some of this charge session.)

The SOC % axis is scaled to correspond to kWh values (both graphs).

It is interesting to note that the SOC % reported by the station (gold dots) does not match the SOC % of the car. We are not sure what causes this discrepancy, but we've seen this consistently in subsequent DCQC sessions.

We expected to need more than 80% charge to make it home, and we wanted to see how to handle getting a full charge after arriving at a station under 50%. So, after the first charging session stopped at the expected 80%, we unplugged and returned the connector to the station. Then we initiated another charging session.

Our second DCQC charge took 36:35 minutes, increasing the car's charge to 266 gids (21.28 kWh, 94.7%). The station supplied 3.609 kWh and the car's charge increased by 3.2 kWh.

At the end of the second charge, the battery temperature was registering 6 bars. Ambient temperature was 61° F.

Driving

We have monitored gids and miles driven over several recent drives. For freeway and combined freeway / surface-street driving we see typical energy use in the range of 250 to 280 Wh/mi, with extreme readings as low as 230 or as high as 290.

The image on the left is after we had driven 74 miles from Tumwater to Issaquah. Stopping for dinner won out over completing the drive home and growing more trees.

Data from our drives to and from Tumwater:

miles	Wh / mi	Notes
65.9	251	Bellevue - Tumwater
79.1	235	Tumwater - Sammamish, slow freeway traffic for several miles

Details on a few legs of the trip from Bellevue to Tumwater.

miles	Wh / mi	Notes
23.6	247	Freeway, uneven speeds (traffic, merges, etc), partially rainy
15.7	255	Cruise at 60
7.1	259	Cruise at 60

Gids in Relation to Bars

The bars are based on an approximation of the percentage of the maximum available energy. This maximum varies with temperature as well as with battery age as capacity is reduced.

Therefore, there is not a static gid-to-bar mapping; it will vary based on current conditions. The image on the right shows gid readings that we observed as bars dropped during driving. It also shows a simple approximation of the gid values at the bar transition points. Since the gid values tend to vary a little anyway, those values should be an easy way to get a pretty close approximation to the actual kWh (gids × 0.08) remaining in the pack. (The gid range will be between approximately 20 × bars + 20 and 20 × bars + 40.)

Don't forget that there is some amount at the bottom (2%?) that is unavailable; the car will shut down before letting you deplete the battery that far.

When we got to approximately 50 gids, the LEAF warned us of low charge with the following:

• Warning message ("Battery level is low") on the dot matrix liquid crystal display just above the steering wheel.
• Illumination of the low battery charge warning light (the icon showing a pump with a plug).
• Flashing driving range (affectionately known in the LEAF community as the Guess-O-Meter).

We arrived home with 35 gids remaining and did not see the turtle.

In September, we finally got our Nissan Leaf. We had signed up very early in the process, and could have had a Leaf in the spring of 2011, but we decided to put our order on hold until they offered the cold weather package. It was worth the wait!

It's now our primary vehicle and we've put just over 2,000 miles on the odometer. Here's our review of the experience so far.

The Good

Driving Experience We've been driving electric since 2008, so it's easy for us to forget how much better the driving experience is with an electric drive train. The accelerator pedal on the Leaf gives instant, smooth response: you push, it takes off. There's no waiting for a gear shift, and no slow climb to full acceleration the way you have to wait for a gas car to rev up the engine speed to maximum torque, then have to shift gears and repeat. It's just smooth, rapid acceleration all the way. I'm sadly reminded of this every time I fly somewhere and am forced to rent a clunky gas-burner.

Braking The Leaf also features regenerative braking. In a gas car, if you want to slow down you have to hit the brakes. This costs you money twice: you're throwing away the kinetic energy of the car and you're wearing out your brake pads. With regenerative braking, you use the motor as a generator to slow the car and charge the battery pack, plus you avoid wearing out the brakes. Even more than the cost savings, regenerative braking shines when going down a hill. In a gas car, you have to ride the brakes or downshift. Riding the brakes is bad as it heats up the pads and can present a safety issues on long downslopes. Downshifting, or engine braking, is better except that you have to chose one of a few gears. With regenerative braking, you can smoothly control your speed with your right foot, whether you're accelerating up to speed, or holding your speed going downhill. Friction brakes work just as on a gas car when you need to stop quickly.

Controls The Leaf has a built-in touch screen for controlling the navigation system and the audio system (AM, FM, CD, iPod/MP3 player, and the ability to subscribe to satellite radio), as well as viewing car information and setting preferences. There are tactile controls on the steering wheel for the audio system and cruise control, and tactile controls around the touchscreen so you can control the vital systems by touch without taking your eyes off the road.

Backup Camera The 2011 Leaf SL package adds a backup camera displayed on the large center console screen. With the camera, it's so much easier to back up whether it's out of a parking spot in a crowded lot, backing into a spot, or just being able to back up against an edge or wall when getting out of a tight spot. I'm now spoiled and miss this feature when driving a car that doesn't have it.

Touchless Keyless Entry The Leaf detects the keyfob wirelessly so that when you are right next to the car, you can just push a button on the handle to lock or unlock the doors or the hatch. You don't have to fumble to pull your keys out of your pocket or purse, which is incredibly handy when you have an armload of groceries. It's the same for starting the car, no fooling with a key, you just push a button and the car starts as long as the fob is inside the car with you. The car knows the location of the keyfob with enough precision that it won't let you lock the keys in the car and can warn you with a beep if you get out of the car without turning it off.

Quiet Ride It's widely reported that electric cars are quiet; some even wrongly claim they are silent. Electric cars don't have noisy internal combustion engines that have to be muffled. At low speeds they can be surprisingly quiet, although you quickly learn to recognize their unique sound even when they creep up slowly behind you. At speeds above 20 mph or so, they make the same noise as a typical gas car does, which consists mostly of tire noise.

That's the story outside the car. Inside the car, it's tricky to do a good job of insulating road noise while keeping the vehicle weight low to maximize efficiency and range. Even if you get rid of the dominant road noise, you just make it possible to hear all sorts of little sounds that you wouldn't notice in a less insulated car. This is especially difficult when there's no engine noise to mask other drivetrain noises. This is the reason for the Leaf's unusual protruding headlights: they deflect airflow around the side view mirrors to get rid of a wind noise you wouldn't even notice in a noisy gas car.

Our two other electric vehicles sound just like the Leaf from the outside, but inside the Leaf is a completely different experience, by far the quietest riding car we've ever owned. I haven't seen the data, but I suspect it's on par with heavily sound engineered luxury sedans that cost far more than the Leaf.

Cold Weather Comfort Because the Leaf uses electric power to heat the car, it doesn't have to wait for an engine to heat up before it can start blowing warm air. The cold weather package (now a standard feature on the 2012 Leaf) adds heated seats (front and rear), heated side mirrors, and a heated steering wheel. If you're driving in the cold, there's nothing more wonderfully decadent than a heated steering wheel. With the cold weather package, the heated seats and the steering wheel get warm even faster than the cabin air.

The cold weather package also adds a battery heater for really cold climates. That's not an issue in Seattle where we rarely see temperatures below 20°F, but is important in more extreme climates.

Remote Control and Monitoring Using a wireless communications system called Carwings, we can monitor the car remotely to check things like the state of charge. The system sends us a text message if we pull into the garage but forget to plug in.

We can also tell the car to pre-heat from our phones. This is something that just can't be done with a gas car sitting in your garage where running the engine would fill the garage, and possibly the house, with deadly carbon monoxide. If the car is plugged in, it uses grid power for the pre-heating, so it doesn't reduce our range. Most of the time, our driving is nowhere near any concern about range, so we use the pre-heat feature even when it uses battery power to warm the car for our return after it has been sitting in a cold parking lot.

Fuel Cost At the US average cost for electricity (11 cents per kWh), the Leaf can drive 30 to 35 miles per dollar of electricity. If gas costs $4/gallon, that's the equivalent of getting about 130 miles per gallon, not in a gutless, rattling economy box, but in a quiet, comfortable car with excellent acceleration.

If the savings in fuel cost is applied to a buyer's monthly car payment, the Leaf is an incredibly affordable car.

Convenient Fueling The Leaf is best suited for local driving, which fortunately accounts for more than 90% of the typical American's driving. If you can use the Leaf for your local driving, you'll find plugging in overnight to be far more convenient than going to a gas station. Especially if you share a car, you've no doubt experienced the rude surprise of needing to make a detour to a gas station, spend time waiting in line, and pump gas when you're already running late. The Leaf is fully charged every morning with just a few seconds of effort required to plug it in at night, about as much time as it takes to plug in a cell phone. Charge time varies with how far you've driven, anywhere from a few minutes to eight hours, but it doesn't matter at all because it happens while you're sleeping.

I know many people think charging time will be an issue, but I just laugh when I see people waiting in a 20-minute line to save a few pennies per gallon at Costco. Driving electric, I pay the equivalent of $0.99 per gallon of gasoline and fueling takes just a few seconds of my time per day. I can only imagine how long the line would be if Costco sold gas for $0.99 per gallon. I get that price and I can charge up in my garage where there's always shelter from the elements and never a wait.

The Bad

Nissan has done an amazing job with their first full production electric vehicle. It's the most comfortable car Cathy and I have ever owned. It's a wonderful car, with no competition whatsoever at any price when considering the comfort and convenience it offers plus the liberation of not being hostage to wildly fluctuating gas prices. However, Nissan got it wrong on two important aspects of driving electric. The good news is that new electric vehicle drivers will get all of the benefits mentioned previously before they notice these more subtle shortcomings.

Increasing Range Anxiety Range anxiety is the irrational fear of running out of power even when an electric car has plenty of range for your driving needs. The way the Leaf presents information about the car's state of charge causes range anxiety. The dash shows in large numbers an estimate of your remaining range. That sounds pretty reasonable, but it has to make an assumption about how you will be driving for the rest of the trip. The Leaf assumes you'll be driving the same as you have been for some unknown period of time. Unless you do all of your driving under exactly the same conditions, same steady speed and constant slope, that estimate is going to be wrong pretty much all the time since it fluctuates wildly as conditions change.

The best information we get is a 12-segment display that displays the state of charge in approximately 8% increments. The problem is you can't tell where you are in the bar. Suppose I drive from work to the grocery store and the gauge drops from 8 bars to 6 bars. That could be from the top of bar 8 to the bottom of bar 6 (almost three bars, or 24%) or from the bottom of bar 8 to the top of bar 6 (just over one bar, or 8%). That's a big difference.

While the estimated range can be useful in some circumstances, Nissan should give us a way to display the car's state of charge as a percentage. I understand that there is some inherent uncertainty in computing the precise amount of energy remaining, but the raw state of charge should be presented to the driver with the same precision as the estimated miles. Having this information would help drivers better understand their energy use and increase the Leaf's usable range. This is such an important piece of information that owners have figured out a way to display the state of charge by tapping into the Leaf's on-board diagnostic port.

Denying the Best Feature of Electric Driving The regenerative braking offered by an electric car dramatically improves the driving experience. Once you get feel of driving electric, it's a joy be able to control your speed with just one pedal: push down to speed up, lift to slow down. Whether it's uphill or downhill, speeding up an on ramp or slowing down for an exit, you do it all with the accelerator pedal. It's far more natural than how it works on a gas car, it's just different from how we all learned to drive. Nissan was apparently concerned about making the Leaf feel as much like a gas car as possible so as not to scare away consumers afraid of change. To do this, they have two modes, normal and economy mode. In normal mode, there's a limited amount of regenerative braking on the the right pedal. In economy mode, there's more regenerative braking, but acceleration is dampened out. You can get the same acceleration in eco mode as normal mode, you just have to push the pedal farther down.

I want maximum regenerative braking, so I always drive in eco-mode. This makes the accelerator less responsive unless I really push it. I would much prefer a more typical pedal response with the maximum regenerative braking. It's also annoying that the drive mode doesn't persist, I have to put it into eco-mode every time I start driving.

Conclusion

Nissan clearly leveraged what they learned from making the world's first factory-made lithium-ion electric car over ten years ago* to create an incredible first generation production electric vehicle.

The comfort features of the Leaf make it worth the sticker price, even if it had a gas drive train. With efficiency that can't be matched by an internal combustion engine and fueled with cheap domestic electricity, the savings in total cost of owning and driving the Leaf make it the uncontested winner in value for its class of comfort and driving experience, in many ways superior to all gas-powered cars at any price. Add in the environmental benefits and the satisfaction of knowing your fuel dollars stay in the US instead of pouring into the global oil market that threatens our national security as well as our economy, and no other car on the market offers the value of the Nissan Leaf.

If you're in the market for a new car, and typically drive under 60 miles per day, and already own a gas car that you can use for those few longer trips, you owe it to yourself to test drive a Nissan Leaf before investing in another gas car.

* The all-electric Nissan Altra built to satisfy California's short-lived zero-emissions mandate from 1997 to 2003.

In 1983, I was a math grad student at the University of Utah. I was a student representative on an administrative committee and heard about a top secret Apple demo where they had been shown a new computer that "looked like it was something out of Star Wars." The next year, every department at the university got two Macintosh computers with 128 KB of RAM, a 400 KB floppy drive, an 8 MHz CPU, and a 512x342 black and white screen.


This was cutting edge, state-of-the art computing, something that, back then, looked like it was straight out of science fiction, and one of them landed in the grad student lounge where we could figure out what it meant.

updated 9/6/2011 2:42 pm: added nerdy charge graph

Last week, Cathy and I took the Roadster for a car show and week of island hopping through Washington's San Juan Islands and Vancouver Island in British Columbia. It was a lovely trip and unique in our EV road trip experiences in that we did the entire 450-mile trip using only 120V charging.

We are frequently asked where we charge our electric cars. The question is often accompanied by a pained expression that tries to offer sympathy for the sacrifice we make by driving electric. The answer is: mostly at home. People are frequently surprised to learn we have found it to be more convenient than going to a gas station.

Occasionally, we take a trip that requires charging on the road. That generally requires planning and finding electric vehicle charging stations. For this trip, there were some charging stations available, but they turned out to be both overpriced and unnecessary. We had chosen B&Bs that would allow us to charge from normal household outlets. On one island this was a big help as there were two otherwise equivalent choices: one that wanted to charge us $20 to use $1.60 worth of electricity and another that said we could do it for free. We gave our business to the one that didn't think we were incapable of doing math. Since we were taking a leisurely tour, and mostly on small islands, overnight charging at 120V was plenty for our daily driving needs.

The convenience of being able to fuel up from any outlet became especially apparent when we drove past this gas station in Sooke, BC.

We were on our way to Port Renfrew, some 45 miles further west along the southern coast of Vancouver Island. Had we been in a gas car, this would have been our last chance to gas up before our return, some 90 miles for the roundtrip plus any side excursions. Because we were in an electric car, and outlets are far more common than gas stations, we didn't care.

At Port Renfrew, we were going to be staying in a yurt at the Soule Creek Lodge. We'd contacted them in advance and knew they had an outlet we could use to charge the car. Charging at 120V only yields about 3 to 5 miles of range per hour of charging, which is painfully slow if you are waiting while you charge, but totally adequate if you're sleeping through it.

Our one night there, we picked up 53 miles of range, which was plenty to get us through the next day's driving.

My only regret for the trip was not getting a photo at Wildwood Manor on San Juan Island where we had deer grazing next to our charging car. Somehow you just never see deer grazing at a gas station.

Nerdy Charge Graph

Here's a graph of our state of charge for the trip. It shows the car's range in standard mode ideal miles, which means we can go that many miles at 55 to 60 mph on the highway, with another 25 miles in reserve.

The first steep dive is the 90-mile drive to Anacortes, WA, to catch the ferry. Then there's a flat spot while we wait five hours after missing the cut-off for the unexpectedly popular first ferry by 5 minutes. Over the next three nights, we charged up overnight on Lopez and San Juan islands working back to a full standard mode (90%) charge, then a fourth charge returned us to full again. There are also a couple of little afternoon charges in there. The fifth charge is in Victoria, BC, after which the car stayed parked for a full day, then we did a range mode charge prior to departing for Port Renfrew. The overnight at Soule Creek Lodge got us back up to the top of standard mode (about 190 ideal miles). Finally, the long 170-mile drive home with a short stop for lunch then a longer stop for the ferry ride. We got home with 10 miles of range left (thanks to my heavy right foot as it became clear we had plenty of charge), plus the 25 miles in reserve. The last spike shows the steep slope of 240V/32A charging at home.

A LEAF could do a pretty similar trip. Depending on the starting point, it might need a little charging on the way to Anacortes (like spending an hour or two at a J1772 charging station at the Burlington outlet malls instead of spending five hours in the ferry line). Instead of spending two nights with a full day in Victoria (where we didn't drive or charge), spend one night in Victoria on the way out and the second night on the way back.