Tom Saxton's Blog

The Tesla Roadster offers a wide variety of charging options, from 120V/12A up to 240V/70A. Charging at higher voltage and current charges faster, but most of the time charging speed isn't an issue. If you drive a typical commute and charge at night, even the lowest power will get the car fully charged overnight. At least with the early Roadster firmware, charging at 120V was pretty inefficient because of the fixed charger overhead, but what about charging at 240V at various amperage limts? My theory was that charging at higher current is more efficient because you spend less time paying the charging overhead, but another owner challenged that assumption with the theory that higher current is less efficient because it generates more heat and thus increases the amount of energy spent keeping the battery pack cool.

Another aspect of charging is that for any given current setting, the Roadster will charge steadily at that current until it gets near the top of the charge, at which point it will start to taper off. This reduces your charge rate near the top of the pack. This aspect of charging isn't documented in the owners manual.

If I don't care about charging time, what's the best amperage for energy efficient charging? If I'm on a road trip and want to squeeze the most range out of time spent at a charging stop, how should I space my stops and how long should I charge at each one? I've collected enough data to shed some light on these questions.

Methodology

I performed a series of charges at various current levels from relatively low battery states up to a full standard mode charge. For each charge, I collected time, voltage and amperage once per minute, and state of charge once every 10 minutes. From that, I can compute energy used during every segment of the charge and the total energy used.

To track our energy use for driving, we have a dedicated electric meter for each of our EVs. To validate my energy calculations, I verified that the total energy calculated per charge matches the value computed from the meter readings.

All charging was done overnight in cool weather with a 2008 Roadster. The 16A charge was done with firmware version "3.5.17 15", all other runs were done with firmware version "3.4.17 15". The 16A charge stopped at a lower state of charge (96%, 188 IM) than I normally see (98%, 193 IM). I don't know if this is due to the lower current limit, the new firmware, or a one-time fluke.

Charge Rate	Wh per Std %	Wh per Ideal Mile
16A	589	306
24A	544	282
32A	527	274
40A	512	266
48A	524	272
70A	516	268

Charge Rate	Ideal Miles per Hour	Current Tapering Begins At:
		Std %	Std IM	Range %	Range IM
16A	13	93	179	82	205
24A	20	94	180	82	205
32A	28	93	178	82	207
40A	36	93	178	81	204
48A	42	91	174	80	201
70A	61	84	161	75	188

Let's assume I want to get the most range for time spent charging, and don't need to charge all the way to the top. From the above table we see that if I'm charging at 48A or lower, I can expect to see the charging rate start to taper off at around 80% or a bit over 200 ideal miles (range mode). If I'm lucky enough to be charging at 70A on the road, my charge rate will start dropping around 75% or 188 ideal miles. I'll keep charging above 40A until I hit that 80%/200IM mark, so if my next charging stop is only 40A, I may as well keep charging to that point.

I'm sure there's some variation from car to car, and the pack and ambient temperatures will change charging behavior, so don't plan your trip to depend on these exact values, but this is at least a rough guide.

Charging Profile Graphs

Let's start by looking at how the state of charge varies over time using different charge limits. All charges are standard mode all the way up and normalized so that all the charge sessions are shown from the same starting point, around 36%. Note that the graph cuts off the last three hours of the 16A charge.



You can see how more current yields a faster charge, and that the rate of charge starts to drop off as the battery pack gets near the 100% mark.

Now let's examine current draw and state of charge throughout each of the current settings. In each session, the car draws an approximately constant amount of current until near the top of the charge when it begins to taper off. The following graphs show current drawn (in amps) and state of charge (as standard mode percent) as a function of charge time in hours. Each charge begins at a slightly different level, but all start below 40% so they have a nice long stretch of steady current draw.







You may notice that at 32A and 40A, the rate at which the SOC increases doesn't drop off as much as you might expect from how quickly the current drops near the end. I attribute this to the SOC calculation stabilizing near the end of the charge. It's difficult to know how much charge is in a battery while you're charging it. My guess is that the SOC is an estimate that gets better near the end of the charge. Regardless, the less current you're drawing, the less power you're putting into the battery. I've seen behavior that leads me to believe that if you stopped the charge within the tapering zone, you'll see the SOC continue to rise for a bit as the software gets a better estimate of the charge in the pack. However, you're still getting diminishing returns on charge time once the current starts to taper.

Another way to look at the data is to plot amperage draw as a function of state of charge. This will show us how the different charge limits compare with respect to when they start backing off from the full allowed current.

In the all-electric Tesla Roadster, Tesla Motors has done an amazing job of designing and producing a car that shows the world how to build a great electric vehicle that is reliable and fun to drive, creating a driving experience that is far superior to that of a comparable gas-burning high end sports car.

Despite having Tesla's example, I'm concerned that Nissan is going to do a poor job with the Leaf. They've already made three missteps which I think need to be corrected before they start selling electric cars.

Overstating the Leaf's Range

Nissan has been saying the Leaf will have a 100-mile range, but they are basing this claim on the LA4 city driving cycle, not on a highway or combined cycle. Tesla says the Roadster's range is 244 miles, and that's a real number. If I drive 55 mph on level freeway, I get energy use consistent with that 244-mile range. From what Nissan has said, I suspect that going 55 mph on level freeway with no heat or A/C will yield somewhere around 80 miles. That's still an awesome range that will meet the needs of many drivers, but it's a disappointment that they entered the game by overstating their range with a number that requires driving even more conservatively than a steady 55 mph.

The vast majority of people who've had the opportunity to drive electric on a daily basis prefer it to driving gas. The only people I've heard of complaining about the electric driving experience are people who purchased an EV with inadequate range for their driving needs. The EV consumer has to take some responsibility to understand their real driving needs and the capability of the EV they are considering purchasing, but any automaker that does anything less than conveying a conservative and realistic picture of the car's capabilities is going to end up with a lot of unhappy customers and a public relations disaster.

Nissan: Get real range numbers out there now. Tesla Motor's detailed page on range information could be better by being far more visible on their site. Make sure the one or two numbers that are most visible to the public are representative of what consumers can realistically expect to get under conditions that are clearly stated. Beyond a simple number or two, also put lots of technical detail out there to satisfy the people who want all of the information and will be the early adopters that clear the path for the mainstream buyers.

Update: I arrived at the 80 mile figure by adding a generous 10% to the 70-mile range for 55 mph with A/C on as reported by Forbes. A MotorTrend article pointed out by mwalsh and evnow on the MyNissanLeaf forum after I published this post quotes Nissan Leaf chief engineer Hidetoshi Kadota as saying normal freeway driving at 60-70 mph without climate control yields a range of 105 miles. So maybe the Leaf's range is better than suggested by the negative Forbes article, but it's still the case that Nissan is not making any of this information available on their web site.

Not Fully Exploiting the Advantages of Driving Electric

Nissan is apparently making the Leaf drive like a gas car rather than fully exploiting the advantages of driving electric. Specifically, they are putting little or no regenerative braking on the accelerator pedal. Tesla does a beautiful job on this. As you press down on the accelerator pedal, the car accelerates more, just as you'd expect. As you let up on the pedal, you get to the point where the car is just coasting before the pedal is completely released. As you release more, the car starts using the motor as a generator to charge the battery, the more you release the stronger the effect. When the pedal is fully released, the regenerative braking becomes quite strong and will slow the car down almost to a stop. (This effect is stronger at slow speeds where you're likely to want to slow more quickly, and lighter at freeway speeds where you want a more gradual slowing to match traffic.) To slow the car more quickly or bring the car to a complete stop, you press the brake pedal to engage the car's friction brakes, just like driving on gas.

After getting used to driving a 2002 Toyota RAV4-EV, which puts only a little regenerative braking on the accelerator with more on the brake pedal, I was dubious of the Tesla scheme. (The Honda Insight and Toyota Prius are similar to the RAV4-EV in this regard.) After driving the Roadster for a few days, I found the Tesla scheme to be much better than the RAV4-EV. It has two big advantages over more closely emulating a gas-burner. For the sake of driving efficiency, I want to slow the car with regenerative braking as much as possible, every time you touch the friction brakes you are wasting energy by converting momentum into heat and brake wear. With the Tesla scheme, I know exactly when I switch from efficient regenerative braking to wasteful friction braking: when my foot moves from the accelerator to the brake pedal. Aside from helping me drive more efficiently, and reducing wear on the brake pads, the Tesla scheme is simply a better way to drive. I can control speeding up, maintaining speed and slowing down all with one pedal. With just a little bit of time behind the wheel, it quickly becomes a more natural and comfortable way to drive. This is especially nice when driving downhill, it's just so easy to control your speed, driving a gas car seems primitive. The only complaint I've ever heard from a Tesla owner about how this works is that they want more regenerative braking on the accelerator, enough to fully stop the car at a light. Personally, I think what Tesla has done is perfect: the mostly one-pedal driving is familiar enough that a first time driver won't have any problem driving the car, with a bit of practice it's a better experience, and the occasional use of the brake pedal keeps my brain-foot connection trained to use both pedals, reinforcing the old skills that puts your foot on the brake pedal instantly when required to slow or stop quickly.

Nissan: talk to some Roadster owners about the pedals. Drive a Roadster for a week or a month. It's important to get this right, it will give your owners a great driving experience sell a lot of cars.

Yielding to Unreasonable Demands for Artificial Traffic Noise

Nissan has yielded to the hysterical calls to add noise to electric vehicles. So far, Tesla Motors has resisted doing the same. All modern cars are quiet when driving slowly; the difference between a pure-electric car and a modern sedan is only audible in very quiet conditions. If quiet cars are a safety issue, then we should be looking at requiring all cars to make a minimum amount of noise at low speeds rather than singling out electrics and hybrids. There is no credible research to suggest that quiet cars are any more dangerous than other cars. Cars are only quiet at low speeds, when both drivers and pedestrians have enough time to react and avoid any problems.

Even if we make electric vehicles noisy at low speeds, they will still be inaudible in noisy environments. If anything, noisy cars that drown out the normal sounds of tires, fans, and pumps are more of a danger than quiet cars. So, if we're really worried about sound-related risks between automobiles and pedestrians, we should have strict laws for all cars that require minimum sound levels at low speeds, and prohibit sounds loud enough to drown out those minimum sound levels. But actually, that wouldn't help either. Just imagine what a parking garage would be like if all cars had to make a constant continuous sound, it would be like having a stadium full of vuvuzelas creating a cacophony that makes it impossible to discern any individual sound while training everyone to ignore the annoying buzz.

Instead of squandering an opportunity to have quieter cars, we should be taking real steps to improve safety for all pedestrians, bicyclists, and everyone else on the road. We should be studying the whole situation to find out if quiet is a real problem for pedestrians, considering all cars -- not just electric and hybrid -- and also the impact of natural or artificial traffic noise on quality of life. Does adding noise to all cars benefit anyone, or does it just crank up the level of background noise and make it harder to hear what's going on nearby? Does adding a constant warning noise to a car just train drivers to expect that pedestrians will automatically scatter out of their way?

I've been driving electric for two years and I have surprised exactly one pedestrian: a woman who was walking backwards into the driving lane of a parking lot while carrying on a conversation with someone across the lot. I stopped and waited for her to realize she was walking into an occupied traffic lane and she eventually saw us waiting for her. She was surprised, but I wasn't, and there was never any danger to anyone. She was clearly embarrassed by what she had been doing and tried to blame her reckless behavior on my quiet car. If I had been going fast enough that her foolishness could have created a dangerous situation, my car would have been making the same tire noise as any other car, which may or may not have been audible depending on the environment.

I'm quite sure that I don't need my neighbor's electric car waking me up at 5 am just because people are scared of unfamiliar technology. I propose that we solve a real problem, like driving while phoning or texting, before we rush into squashing a quiet car advantage in response to uninformed hysteria.

Nissan: Please give your drivers a manual way to alert pedestrians with something less obnoxious than a blast of the car horn. GM did this with the EV1 and owners loved it. Hold off on making a constant noise until there's enough research to show quiet cars are a danger and we have a validated way to improve the situation for all cars -- electric, hybrid, or gas-burning.

Edited July 5, 8:46 am: corrected technical error in description of Tesla's regen algorithm and clarified pedestrian surprise story.

Edited July 5, 3:20 pm: added update on more optimistic Leaf range numbers as reported by MotorTrend.

If you are interested in driving an electric vehicle, I'd like to tell you how to ensure that you'll have a great experience, or at least make sure you don't have a disappointing experience.

Here's the secret formula for EV success: make sure the range of the vehicle suits the driving you plan to do with it. I know that sounds pretty obvious and easy, but there are two big barriers to success: bad reporting in the media and obfuscation by the automakers. There's also a bit of complexity: just like gas mileage, you can't express EV range with a single number. I'll get that all straightened out from the perspective of someone who has been driving all electric for almost two years.

In addition to the general facts of driving electric, we recently got some more specific range numbers for the upcoming Nissan Leaf which I'd like to put into perspective for potential buyers.

Reporting the Obvious and Irrelevant

If you follow EV coverage in the press, you'll find a steady stream of articles from reporters who think they've discovered the flaw that will deflate all of the hype about EVs. Their basic premise is that EVs won't work because they take too long to charge and there's nowhere to charge them. These articles are either totally made up, or based on the bad experience of a single EV driver and don't represent the real experience of the majority of EV drivers who purchased a vehicle appropriate for their needs. My purpose here is to make sure you don't become the excuse for some lazy reporter to write yet another of these uninsightful articles.

Would a newspaper publish an article about a Ford Focus owner who was disappointed that he couldn't fit his wife and seven kids in the car? How about a Honda Civic owner who's mad her car isn't suited for towing an RV? A Hummer owner who's mad about how much it costs to drive a mile? Of course not, these would be laughably obvious mistakes made by the owner in choosing a car.

For the consumer properly informed on the benefits and limits of electric vehicles, it's equally obvious that buying an EV with a 75-mile range to do a daily 74-commute with no charging infrastructure isn't going to yield a happy driver. That's obvious and boring.

The real story is that there is no problem with range or lack of charging infrastructure if you can just charge at home to meet your driving needs, instead it's a real convenience not to have to fuel your car away from home. So let's see if you qualify...

The Rule

To be a happy EV owner today, you want to buy a car that has enough single-charge range to handle all of your daily driving with a reasonable buffer for typical errands without needing to charge anywhere other than your charger. (Your charger is probably installed at your home but might also be at your work location.)

The good news is that for most drivers, the required range is surprisingly low. A 2003 US Department of Transportation survey (PDF) found that 78% of Americans drive less than 40 miles a day. If you're in the 78%, and don't often have big exceptions to that daily commute distance, then an EV that gets at least 70 miles of range in your driving conditions will most likely make you one happy camper. (But keep reading to learn how to evaluate EV range.)

Starting this fall, we'll start to see a lot of chargers getting installed in a few metro areas in the US and other countries. As this happens, and EV ownership goes up, more and more charging will become available and convenient. As that happens, charging away from your home charger will become more dependable and the usable range of EVs will expand as a result. For example, if you can charge at home and at work, then the usable range of an EV is doubled because you only need to travel one way on a single charge (with a reasonable buffer).

Since there's going to be limited availability of affordable, practical, freeway-capable EVs in the near future (as in zero today, and a few thousand Nissan Leafs starting to trickle out starting in December of this year, then more from other automakers to follow), it's OK if the first few models of EVs don't work for you, they will work for millions of potential buyers. Wait for an EV that will be right for your driving needs.

The Win

After you've driven electric for a month, spending just a few seconds to plug in each night to start every day with a full charge, without ever having to stop at a gas station, you'll wonder how you ever tolerated the hassles of driving a gas burner.

In addition, the experience of driving electric is just better: you get instant acceleration without waiting for the engine to rev up and the transmission to shift, another nuisance of driving gas that you'll only notice when you get used to driving without it.

Bonus: no tailpipe emissions, low-to-zero emissions from electricity generation, and never having to worry about the price at the gas pump.

Evaluating EV Range

Just like gas mileage, EV range can't be expressed as a single number. Even the two EPA city and highway gas mileage numbers you see on vehicle stickers don't tell the whole story. This is such a big issue with gas cars, the caveat "your mileage may vary" has become part of our cultural vernacular.

Let's start by going over how gas mileage works. Those gas mileage numbers on the sticker in the window are determined by driving the car on two standard EPA driving profiles meant to simulate typical driving conditions, which have been recently revised to better represent actual driving conditions by including things like using air conditioning on part of the cycle.

Gas mileage depends on a number of factors, including passenger and cargo weight, HVAC use, start/stop frequency, road incline, rain/snow, and so forth, but the biggest factor is speed. At low speeds, gas mileage suffers because there's an overhead of running/idling an engine that burns fuel whether you're moving or not. Stop and go traffic is also bad news, because you invest energy in speeding up only to throw all it all away by converting your car's momentum into heat plus wear and tear on your brake pads. At higher speeds gas mileage suffers because wind resistance goes up rapidly with speed, so much so that it takes more energy per mile in a way that starts increasing dramatically at the low end of freeway speeds. Somewhere in the middle, at a moderate, steady speed, is where you get your maximum gas mileage.

Electric vehicles behave similarly, except they get punished less in stop and go traffic because, like hybrids, they can slow down with regenerative braking wherein the motor is driven by the drivetrain to act as a generator to put charge back into the batteries. This not only improves energy efficiency, but also reduces brake wear.

Given this complexity, how can an automaker tell you how your gas or electric car will perform under your driving conditions? Answer: they can't.

While you can argue that it's even more important to understand energy efficiency (in the form of single-charge range) for an electric vehicle, there's the ugly truth about burning gas that no one likes to talk about: it's no good for predicting long-term fuel costs. With a proliferation of gas stations everywhere, range isn't something you think about for a gas car. What you do think about is your pocketbook. Better mileage means cheaper stops at the gas station. While knowing your gas mileage might tell you what you'll be spending at the pump this month, it doesn't say anything about what you'll be paying next month or next year. Anything from a hurricane, to Wall Street speculators, to a political action by OPEC, to the whim of some oil nation tyrant can cause gas prices to double by barely nudging the precarious balance between world oil supply and demand. Electricity rates are far more stable, especially when it comes from renewable sources that aren't subject to the unpredictable economic forces that rule the world's fossil fuel energy market.

How can a potential buyer figure out if a given EV has the range required to convert from the hassles of driving gas to the joy of driving electric? Read on...

Case Study: the Range of a Tesla Roadster

For most people, buying a $109,000 two-seat sports car is totally out of the question, whether it's a gas-burning Ferrari or an all-electric Tesla Roadster. Being able to go from 0 to 60 mph in under four seconds isn't going to get the kids to school or bring home the groceries from Costco. But, as of this writing, Tesla Motors is the only automaker selling a production, freeway capable electric vehicle in the US. If you dig a little, their web site provides a wealth of information about driving electric that will be of help to any potential EV driver.

The best illustration I have found of the effect of speed on efficiency, and thus range, is this graph from Tesla Motors showing how the Roadster's range varies with speed, while holding other factors constant at favorable values (constant speed, no AC, no driving up a mountain, etc.).



The EPA range number for the Roadster is 244 miles. From the graph, you can see that you get that range driving at about 55 mph. If you have to pick one number to describe range for a Roadster encompassing city and highway driving, this is a pretty good choice, and it's a real number that I've personally verified as much as possible without actually driving the car until it stops. Likewise, the value of about 180 miles for 70 mph matches my real-world experience. Simon Hackett and co-driver Emilis Prelgauskas came close to the graph's 34 mph range number by driving 313 miles on a single charge in Australia last year. Perhaps someone will be patient enough to try out the 17 mph peak on the graph at over 400 miles of range, but that would be a very long drive!

I'd say Tesla did a good job here, picking a reasonable single number for stating range based on some combination of the EPA city and highway cycles. They also provide the graph showing the whole story, at least with respect to speed, although to find it you have to dig down into their blog entries to find the article with the graph and full explanation.

But there's a bit more to the story that requires more digging. The above range numbers are for using the entire battery charge from full to empty, something you really don't want to do on a regular basis because it's not good for the life of the battery pack. For normal daily driving, you don't need 244 miles of range, so Tesla provides a "standard" mode of charging that only uses the middle 80% of the battery pack. This will extend the life of the battery pack and still give you 200 miles of range at 55 mph, or about 160 miles at 70 mph. This is between four and five times what most of the drivers in the US need for their daily commute. For daily driving, the range of the Roadster is ridiculously high. Going on a road trip beyond the single charge range is doable, but it requires patience and planning. This situation will get a lot better as high-speed charging stations start to appear later this year.

The numbers also get worse in really hot weather. Last summer I drove from Portland to Seattle in 100-degree weather, about 180 miles. This trip is easy at 55, in fact even at 65 mph it's no problem. But this trip, with the HVAC system using energy to keep the battery pack cool, it took getting off the freeway and careful route planning to reduce both distance and speed to get home without having to stop for a partial charge.

The upshot: if you live in an extreme climate, with either a lot of sub-zero winter days or 100+ degree summer days, you'll want to add more buffer to your required EV range.

The last big issue is aging of the battery pack: as the battery pack ages, its capacity will decrease gradually over time, then drop more rapidly as the battery pack wears out. Our car is performing the same as it did when we got it one year and 9,000 miles ago. Other Roadster owners have crossed the 20,000 mile mark, and so far I haven't heard of anyone noticing a loss of range. Tesla's battery pack warranty is only 3 years or 36,000 miles, which is in line with other high performance sports cars, but is a bit underwhelming compared to their statements of expected battery life, seven years or 100,000 miles. Nissan says their battery pack should last 10 years, and because the Leaf is a much more mainstream vehicle I expect they will offer a much better battery warranty.

Still, if you're planning to drive your new EV for 5 to 10 years, it's not going to be smart to buy an electric car that's right on the edge of meeting your needs with its full factory-fresh range.

Our Electric Garage

In July of 2008, while we were waiting for Tesla to build the Roadster we reserved in 2006, we were fortunate enough to buy a rare 2002 Toyota RAV4-EV from its original owner in Berkeley, CA. If you've seen Who Killed the Electric Car, then you've know what a great electric driving experience the lucky few drivers had during the brief period where California required all of the automakers to find a way to reduce tailpipe emissions to zero.

When we got the RAV4-EV, we expected it would take care of about half of our driving. We were wrong by a wide margin: it took over 95% of our driving. The only time we burned gas was when we each had to be different places at the same time. Despite our EV enthusiasm, we were range anxiety victims and overestimated how much range our driving really required.

In our experience, the RAV4-EV gets about 100 miles per charge. Even staying out of the top 10% and bottom 20% of the battery pack means we can drive 70 miles per charge under our typical driving conditions, and can handle any driving conditions with enough range we don't generally have to think about it.

When our Roadster finally arrived nearly a year later, we were totally converted to the electric driving experience. Having a second electric car meant we didn't have to choose which of us got to drive the smooth, quiet car.

Our hope is that the Leaf will bring this sort of EV capability into the mainstream in an affordable, practical, safe vehicle.

Nissan Leaf Range Numbers

The first range number we heard for the Nissan Leaf was 100 miles using the EPA's LA4 drive cycle. Darryl Siry gets credit for being the first to point out that the LA4 drive cycle is a poor choice for describing EV range as it's a city driving cycle that's nicer to the range than the combined city/highway drive cycle that is used by Tesla. Siry also wrote a great piece on the issues with range numbers and the need for federal regulations on how they are reported which added perspective to my personal experience and helped inform my writing here.

On June 19th 2010, we got some more range numbers from Nissan via Forbes. To summarize:

• Cruising at 38 mph in 68-degree weather: 138 miles.
• Suburban traffic averaging 24 mph, 77 degrees: 105 miles.
• Urban highway, 55 mph, 95-degrees, A/C on: 70 miles.
• Winter city driving, 14 degrees, averaging 15 mph: 62 miles.
• Stop and go urban traffic averaging 6 mph, 86 degrees, A/C on: 47 miles.

The Forbes article is typical anti-EV fear mongering, the facts presented with pithy commentary but no critical analysis. Have you ever read an article on how your gas mileage drops in stop-and-go urban traffic during the heat of summer or the cold of winter and how much that's going to cost you when you're driving your gas-guzzling SUV? Of course not. But you do hear about how it will affect the range of an EV that isn't even on the roads yet. It's great to get more facts, but try to ignore the hand-wringing hysteria that makes it sound like the federal government is about to repossess all of the gas burners and force everyone to drive a Nissan Leaf.

The fact is, the Leaf doesn't have to meet the needs of every driver in the US. It just has to meet the needs of the few thousand people lucky enough to be able to buy one in the next year. Even that worst-case 47 miles is going to be good enough for millions of drivers now (remember that 78% of US drivers commute less than 40 miles per day) and good enough for even more drivers when there are convenient chargers at workplaces and malls.

Is the Leaf's Range Right for You?

I think the best way to figure out what range an EV needs to have to suit your needs is to monitor your driving. Just write down your odometer when you get home each night. From that, you can figure out how far you actually drive. Be sure to get not only your regular daily commute, but also some examples of exceptional days with extra appointments, shopping, detours, etc. If you have an additional vehicle that would supplement your EV, throw out any long drives that you would choose (in advance) to handle with that vehicle. Then add a buffer for the unexpected, and, if it applies, more buffer for the extreme driving conditions that reduce range.

People who haven't driven an EV will be tempted to always have half of the battery in reserve for surprises, but most experienced EV drivers are very comfortable driving down to 30% or even 20%. (With the Roadster where I get great feedback on the state of charge and know it won't hurt the battery, I have no problem driving down to 10%. With the RAV4-EV, which gives less precise info, we try to stay out of the bottom 20%.)

If you commute 70 or more miles per day in a city that regularly has horrible traffic, freezing cold or sweltering hot days, and isn't planning for charging infrastructure, then don't buy a Leaf to be your only car this year. Wait until the cars and the charging better suit your driving needs. There are more than enough of us to buy up every single Leaf Nissan can make in the next 12 months, so don't become fodder for another annoying article about how EVs are impractical because someone bought one that's not suited to their driving.

If the Leaf's range numbers do suit your driving needs and you want to get an early start driving electric, then sign up, right now. They are going to sell fast. But before you fully commit to a purchase, get the information you need to determine if the Leaf will meet your needs, and get that info directly from Nissan. Don't depend on a conversation with your local auto sales drone.

I'm glad we have learned more about the Leaf's range months before anyone will be committed to buying one. Next up I want to see a graph like Tesla gives for the Roadster range vs. speed under optimal driving conditions. I also want to know if the range numbers given are for using the full battery to its maximum range, or if they include allowance for the reserves at the top and bottom of the charge cycle needed to maximize battery life.

If the Leaf will meet your needs, you won't regret switching away from gas. The benefits of charging convenience and drivability are great motivators to be among the early adopters to buy one of the first mainstream factory electric vehicles.

On March 17, six Seattle-area Tesla owners joined the Evergreen Lotus Car Club for a track day at Pacific Grand Prix, the new smaller track next to Pacific Raceways in Kent, WA. The folks at Pacific Grand Prix were excited to have a bunch of Tesla show up. We were treated to unseasonably nice weather, clear and sunny except for a brief hail storm.

Trevor Cobb of the ELCC did a wonderful job of organizing the event and we really appreciate his invitation to the Tesla cousins.


The track is 30 feet wide and 0.8 miles long. It's used for go cart rentals as well as track days for full size cars. As you can see from their web page, the track is all about turns with just a couple of short straightaways, so the speeds are kept under control. There were no timers on the track, so it was all about learning the track and improving your own driving. I did some autocrossing in the mid-90's, so this was somewhat familiar territory, although less forgiving of big mistakes. (The day went fine, the only notable off-course driving was a Lotus driver who sprayed dirt all over the track with no harm done to car or driver.)

A couple of months ago, the Pacific Grand Prix folks attended a Seattle Electric Vehicle Association meeting to let the community know they are supportive of EVs. At that meeting, Daniel Davids, long-time local EV advocate and now president of Plug-in America, offered up some tips to the group from his extensive track-driving experience. So, when I got the email from Trevor inviting the local Tesla owners to join in on their track day, I offered to Daniel that we could split the driving if he'd give me some pointers. He accepted.

We arrived at the track at 8:00 am, drivers meeting at 8:30 and the first group hit the track at 9:00. The second group was the six Roadsters. We got 15 minutes of driving, then about an hour wait between runs.

I took the first run and Dan talked me through it, helping me to improve on each lap. Between runs Trevor offered up some helpful tips also. On the second run, Dan showed me what a Roadster can do with a skilled driver behind the wheel. It was a little frightening at first, then I could see that he knew what he was doing and that I was in a for a real treat. Dan just swept through the turn combos where I was struggling with the steering wheel. He made everything look smooth and easy, except for figuring out how the passenger is supposed to hang on through all of that lateral acceleration without a steering wheel to grip. After seeing it done well, my run in round 3 was greatly improved.

Depending on the driver, each run was consuming between 3 and 7 ideal miles per driven mile. On my first tentative run, I used 21 ideal miles in 7.5 actual miles. Rich, an accomplished track/autocross driver, used 36 ideal on that same run. Dan managed to burn 35 ideal miles on the second run, even though he exited the track after only 5.2 miles.

It was also fun to compare the recent energy use screens between me and Dan. Here's mine after the third run:


You can see I averaged 761 Wh/mi over the last five miles after the cool down lap and exit from the track. In normal driving, the average is more like 260 Wh/mi, with occasional green spikes for acceleration, but here it's solid green with dips for occasionally getting off the pedal. Doing the math from the trip meter says I used 841 Wh/mi for that run. Now, here's Dan's graph from the second run:


There is no letting off the pedal for Dan, at least not for long enough to show up on the graph, and the graph is pegged at 999 Wh/mi. Doing the math from the trip meters says Dan averaged 1,423 wH/mi on that run.

There was supposed to be 240V charging at the track, but there was a problem with that circuit, so we searched out all of the 120V outlets around the track and charged as much as we could. Even with that little charging, I had plenty of charge for the 25 miles home when I had to leave around 3:00, I could have easily stayed for the last run. Others who had a longer drive were charge constrained and had to leave early. The track folks are very open to getting better charging installed, so future events should be easy for everyone.

Cathy and I are both puzzle nuts. We have two daily puzzle calendars to jump start our brains during breakfast. Cathy has a diverse taste in puzzles and is frequently working her way through a book of Japanese puzzles while I'm reading the newspaper at night. I'm not talking about Sudoku, she chews through puzzles like Kakuro and Hanji.

In addition to solving puzzles, she also likes to create puzzles, which is much harder and far more time-consuming than solving them. Quite often, I get a sequence of puzzles on my birthday each of which has an embedded clue to the next puzzle, eventually leading to my birthday gift.

This year we were extremely busy for the two weeks leading up to my birthday. We spent a week in Hawaii prepping our condo for a new rental agency, then spent the next week being EV groupies attending all of the Nissan Leaf events in Seattle, then on Saturday Cathy was the head judge at the Washington State FIRST LEGO League Championship. Anyway, we were busy and I was sure Cathy didn't have time to create any puzzles.

So, I was quite to surprised to find a puzzle sitting on the bar at breakfast. I like doing Marilyn vos Savant's Numbrix puzzles that accompany her column in Parade magazine, so Cathy created a jumbo size version. This is probably the only puzzle format for which I am more practiced at solving than Cathy, but she still managed to create a puzzle in that format, larger than normal, challenging for the type, and yet still solvable.

It was a good puzzle and I enjoyed solving it. If you want to try, download this PDF version. When I was done, I was amazed she had created such a nice puzzle and couldn't imagine when she had time. I wondered if it was the first clue of a treasure hunt, but I didn't want to assume it was and have her think I was disappointed to have just a single puzzle. I also couldn't imagine how solving a Numbrix could yield a clue to another puzzle. While all of this was running through my brain, she was giving me the look that says, "you're not done yet." Stop reading now if you want to try to find the clue to the next puzzle without a hint.

While I was solving the puzzle, I realized that sometimes when I work these puzzles, instead of writing in the numbers, I just draw the path through the sequence connecting the centers of the boxes in order. It actually occurred to me that might be interesting, but I couldn't imagine how that could yield a message. Cathy realized that by drawing lines in the manner I described, there are 7 letters that can be easily formed: CEHISUY plus maybe a couple of others like T and L that might work but leave odd shaped areas to be filled to complete rectangular blocks. If you solve the puzzle then draw the sequence line you'll see a word that told me where to look for the next puzzle.

If you'd like to try working this one on paper, download the PDF version. Four of the clues require a bit of inside knowledge, but it's probably doable anyway. Stop reading now if you want to try it without any hints, if you perhaps know the cars we drive, enjoy shows at the Village Theatre and were an applications programmer at Microsoft in the 1990s.

1 Down is a reference to the Hungarian naming convention used by some programmers at Microsoft where "max" means "one more than is allowed." This photo of one of our cars  will give you the answer to 4 and 6 Down. 25 Down is a reference to a line in Chasing Nicolette, but you can probably get it from the other clues without knowing the show.

For the month of November, I drove the Roadster 762.2 miles. That's mostly with just me in the car driving a variety of city and highway miles. I tend to drive enthusiastically most of the time, but the month also included a roundtrip drive to Longview, WA on cruise control at 55 mph.

During the month, I put about 247.8 kWh into the car from the wall (213.3 kWh metered from my garage plus approximately 34.5 kWh from an unmetered NEMA 14-50 outlet in Longview). That's 325.1 Wh/mi and includes charging losses, battery pack self discharge, heater, headlights, etc. That's my wall-to-wheel number and is based completely on things I can measure.

From July 25th to August 27th, I drove the Roadster 696 miles and pulled 234 kilowatt hours (kWh) from the grid, giving us 336 Wh/mi. That included some hot weather and four 1/4 mile runs at Pacific Raceways.

On individual charges, I see efficiency vary from 240 Wh/mi to over 400 Wh/mi, and obviously much higher for things like drag racing.

I charge consistently at 240V and 40A at home. In Longview it was 230V and 40A. Because of charging overhead, I assume I would get slightly better charging efficiency if I charged at home at 70A. So, my numbers are just that, my numbers. Another driver would get different numbers depending on driving, weather, road conditions, and charging habits.

The EPA estimates documented in the paperwork for our car say 260 Wh/mi city and 290 Wh/mi highway. I've seen information from early 2008 Roadsters that had the EPA numbers and 340 and 360 Wh/mi.

You may have heard Roadster owners talk about numbers well below my 330 Wh/mi numbers. These are most often the number reported by the car's info screen which are not wall-to-wheel numbers, and in fact are (as far as I know) not at all documented as to what that number means. I have figured out some things about the numbers reported by the car, which I'll now explain.

For the month of November, the Roadster's trip meter says that I used 207.9 kWh, and thus 272.8 Wh/mi. But what does that mean? Did I push 207.9 kWh into the motor, or is that net of energy pushed back into the pack from regenerative braking (regen)? Does it include energy used to run the accessories and/or running the coolant pump and fans during charging?

On the "Energy History" screen, the Roadster tells me my "net energy used" for the month was 233 kWh and that I got 26 kWh from regen. What does "net" mean? I would assume that "net" means "net of regen," i.e., power from battery pack minus power into battery pack from regen. Except, if I compare those numbers to what the trip meter says, I notice that 233 - 26 = 207, which is suspiciously close to the energy use number reported on the trip meter.

From that, I infer that the trip meter's number is net energy use from the battery pack (power drawn minus regen put back in), and thus the so-called "net energy" from the energy use screen is really the gross energy pulled from the battery pack including energy that went into the pack from both wall charging and regen charging.

Do these numbers include the energy spent on accessories? Is the difference between what I put in through charging (247.8 kWh) and the car's reported net energy use (207.9 kWh) just charging losses or does that also include accessory use? I have no idea.

The only number I can stand behind, and the only number I can compare with other electric vehicles, is the wall-to-wheel number. The efficiency number reported on various of the Roadster's info screens is useful for understanding how driving style and conditions affect efficiency and for predicting/optimizing range, but is seemingly useless in any other context.

I believe the same is true of any efficiency number for the Leaf given out by Nissan, or any other EV manufacturer or driver, unless that number is as clearly defined and directly measured as the wall-to-wheel number.

It used to be that the Tesla screen reported an energy number after each charge that was much lower that what was actually drawn from the wall. I suspect that was the energy that actually made it into the battery pack, but I never saw it defined by Tesla. More recent firmware versions are reporting a number that is close to the number I read from the wall meter (and averaging multiple consecutive readings together agrees to within 1% of the wall reading). This is a big step forward for drivers who want to monitor their actual wall-to-wheel energy use and efficiency, but don't want to go to the expense of installing a dedicated meter. It would be a real benefit to the Tesla community if Tesla would (a) define the number they currently report and (b) make the energy drawn from the wall across multiple charges easily available.

Regarding range on a single charge, my personal record is 192 miles driven with a passenger in 100+ degree weather starting with a bit less than a full charge and ending with 10 miles of range left. On the trip back from Longview in cool weather, I drove 136.9 miles using cruise control at 55 mph using 55% of the battery. To the extent that you can extrapolate that to the full battery, that figures out to about 249 miles of range. On the trip down to Longview earlier the same day, also using cruise control at 55 mph, it was raining and colder, so I had the wipers, headlights and heater on and used 65% of the battery pack, for an extrapolated range of 208 miles.

My car is a 2008 Tesla Roadster with firmware version "3.4.15 15" (upgraded from "3.4.13 15" on 11/15/2009).

Edited at 10:23 pm on 12/13 to correct typo in second paragraph.

Today, Cathy and I both got to drive the Nissan Leaf test vehicle, apparently a Nissan Versa outfitted with the Leaf's drivetrain. Coincidentally, last week we rented a Versa on vacation, so we were treated to a virtual side-by-side test of gas versus electric. They had a course laid out with cones in a parking lot, which I treated as a small autocross course. The test vehicle handled well and had good pick-up, better than the gas-burning Versa.



Most interesting was how quiet it was. The Roadster has a loud gearbox whine when accelerating, plus road and wind noise. The whine is much quieter than a gas engine doing similar acceleration, but it's not silent. The RAV4-EV has a comparable road noise level, maybe a few dB below the Roadster and minus the loud drivetrain whine. Both the Roadster and RAV4-EV are about 7 to 8 dB noisier than Cathy's parents' Honda Accord doing 60 mph on the same section of average freeway surface. (We measured all three vehicles with a Radio Shack sound level meter.) The Nissan test vehicle was very quiet from the inside, I think quieter than the Accord, but we didn't do any measurements. From the outside, you hear the same tire sound you hear from any decent modern sedan.

Before buying, I'd want to take it for a real test drive, get it up to speed on the freeway, etc. That said, based on our test drive today, I'd highly recommend it to anyone who is an early adopter, very interested in driving an all-electric family sedan, and whose driving habits could be met by the Leaf's range.

That assumes that Nissan doesn't bungle the whole thing by forcing buyers into some ludicrous over-priced battery lease.

On Monday, the weather was too nice to not be out driving so I decided to take a spin up to Mt. Rainier to see if the roundtrip could be done on a single charge. Thanks to Todd Laney for planting the seed by suggesting it as a possible Roadster owner drive route to follow our adventure on Sunday.

I used Google maps to plot a route and get mileage/time estimates. Google estimated the drive at about 2:30 and my goal was to make the roundtrip in four hours. On the way back I took Highway 18 instead of Cedar Grove Rd SE, which wasn't that scenic and smelled of landfill.

I left our house at 4:00 pm, with a full standard mode charge at 194 ideal miles. I reset the trip meter so I could easily track mileage and energy used. I left later than I had hoped, and I paid for it by being stuck in traffic pretty much the entire way from Issaquah to Enumclaw. That didn't help with my four-hour goal.

Give or take a few stunning views of Rainier near Black Diamond, the drive didn't get fun until I left Enumclaw (and the traffic) and got onto SR 410, a two-lane road through forest. I was pushing to make up lost time, but mindful of the risk of deer crossing the road, so I kept the speedometer at or a little above the speed limit. I didn't see much traffic and only passed one vehicle, a van going well below the speed limit.

I neglected to record state when I entered the park to begin the ascent up the mountain, but I recall the battery being around 90 ideal miles and the trip odometer would have been around 70. At about 4 miles from Sunrise, the trip and battery state crossed at 79 miles driven and 79 ideal miles left in the battery pack. If I were on level ground, I would have been considering bailing at that point, but I knew I had used extra energy climbing that I would get back on the descent. Also, I was still driving in standard mode, so I could switch into range mode to get another 25 miles of range.

The best part of the drive was the winding ascent up the mountain, wonderful conditions for the Roadster, although the road was pretty uneven in spots. I was having fun but not being crazy about it. Two thirds of the way up the mountain, I came up behind another car and resigned myself to taking the rest of the drive at his pace, which would have been fine. However, as soon as I came up behind him, he immediately pulled over to let me pass. I don't know whether he was scared of the red sports car, or just really nice. I waved in appreciation as I passed.

I arrived at Sunrise at 6:08 pm, just a few minutes later than my goal time. I let the car sit for a few minutes while I tracked down a restroom and snapped a quick photo. Ready for the return drive, the trip meter said I had driven 83.7 miles and used 28.01 kWh. The touchscreen altimeter said 6300 ft, temperature at 60 F, with the SOC at 47% and 69 ideal miles (standard mode).



For the descent, I got regen nearly the entire way. I stopped twice on the way down, once at the viewpoint just below Sunrise where I got my cell phone signal back and called to update Cathy on my progress, and at the bottom to record data. At the park exit, 14.0 miles from Sunrise, the battery state was up to 71 ideal miles, a net gain of two ideal miles from the reading at the top.

I was treated to a beautiful sunset with a thin crescent moon just above the horizon as I was finishing up the drive on SR 410 approaching Enumclaw.

I had a TomTom GPS navigation device programmed for the route home, mostly to show me remaining miles and ETA. When I left the summit at 6:20 or so, it was predicting I would get home just before 9:00, which was obviously wrong since I made the trip there in just over two hours. After exiting the park, the ideal miles tracked the remaining miles pretty closely, showing a buffer of about 10 miles the entire way, while the ETA dropped steadily.

I got home at 8:20, missing my four-hour goal by about the length of my stops. The trip meter read 168.8 miles and 41.76 kWh. Our house is about 100 ft elevation, so the trip involved climbing then descending 6,200 feet. The battery pack was showing a temperature reading of four (the highest of the blue ticks), PEM and motor at 3. After sitting for 20 minutes to stabilize, the state of charge read about 5% of the battery left, 9 ideal miles.

Charging back up to full (standard mode) from 240V/40A took 5:20 and put 44 kWh back into the battery pack. The meter on the wall indicated it pulled 50.0 kWh hours, or 296 Wh/mi from wall to wheel, about 12% below my average of 336 Wh/mi.

If Watt-hours per mile doesn't mean anything to you, at 9 cents per kWh for "green power" from Puget Sound Energy, it cost me about $4.50 to drive 168.8 miles, or about 37.5 miles per dollar of green electricity.

My take-away from the drive:

• The roundtrip can be done on a single standard mode charge, but if you have a passenger or are farther away than Sammamish, I'd recommend a range mode charge.
• If you do it on a weekday, start early enough to avoid the evening rush hour.
• Take a credit card: it costs $15 to get into the park via the automated kiosk. Cash might also work.
• Driving through the woods at sunset on a warm day leaves the front of your car covered with a thick layer of bugs.
  

I joined four other Seattle-area Tesla owners in driving down to Portland for the NEDRA Wayland Invitational IV electric vehicle drag racing event at Portland International Raceways on July 24th and 25th. My friend Richard wasn't due to receive his 2010 Roadster for another week or two, so he and I shared the driving and the racing in my car.

None of us had any previous drag racing experience, we were just doing it to promote electric vehicles by showing a bunch of people that EVs can be as fun and powerful as gas-burners without sending a bunch of our our dollars overseas or dumping CO2 into the atmosphere.

Over the two days, thanks to Northwest Handling Systems, John Wayland, James Morrison, and several others behind the scenes, who arranged charging both on and off the track, I was able to post the best time in a 2008 Roadster: a 12.982 second 1/4 mile ET at 103.48 mph. The best Roadster time was set by Scotty Pollacheck (the professional driver/rider of the famous Killacycle) in James Morrison's freshly-delivered 2010 Roadster sport: 12.643 second 1/4 mile ET at 102.89 mph.

At the Wayland Invitational, I got to race head-to-head against other 2008 Roadsters using the same driving technique and as well as controlling other parameters. Having Richard racing in my car allowed me to compare how weight changed times with other parameters held constant. Also got to race against the famous White Zombie. We had two nights there, one with charging at the track and one without. My YouTube channel has some videos from that weekend.

Two weeks later, the same group of owners spent another evening at Pacific Raceways in Kent, WA this time with Richard driving his shiny new 2010 Roadster. I was able to do some more experiments there.

Based on what I've seen so far, it breaks down like this:

13.40 seconds: 2008 Roadster, medium weight driver with a cool battery pack, single foot start, traction control on, racing in warm weather at sea level.

0.32 seconds - having a warm battery pack from a recent 240V/40A charge
0.10 seconds - traction control off
0.07 seconds - lose 20 to 30 lbs of driver weight
0.07 seconds - two-footed start (indirect estimate)

I didn't compare single foot launch and two-foot launch with all other parameters controlled. From otherwise similar runs in Portland and Kent, I saw a difference of about 0.07 seconds, but that was different tracks, different charge profiles and different ambient temperatures. The other delta were pretty well controlled.

One owner in Portland increased tire pressure to 40 psi all around trying to shave off a few hundredths to break into the high 12's and didn't get any benefit.

There's also some variation from car to car depending on how well the motor was wound, etc. While there was about 0.07 seconds difference between Richard and me in my car (presumably due to weight), there was a much smaller difference between Scott in his car and me in mine (0.04 seconds) even though I would guess the weight difference to be similar.

I didn't sense the stock tires spinning even with a two-foot launch and TC off, so I don't see how sticky tires would help on a 2008 Roadster. I have confirmation from Tesla to not expect the 2008 Roadster to spin the stock tires with TC off when on dry pavement and driving in a straight line. (That said, I am not recommending turning off TC in any other circumstance.)

I didn't get a chance to try all of the optimizations on the same run. It was only on the second day of the Wayland Invitational that I had a chance to charge up at the track and that was before I learned about the two-foot launch technique in detail, and also before I had the nerve to turn off traction control. So, I don't know what happens when you stack up all of the techniques together.

According to my data, getting a stock 2008 Roadster under 12.8 is going to take a trick I don't know about. Perhaps a driver under 100 lbs, or driving at higher altitude could do it. It might also help to fold back the side mirrors to reduce drag. It will be interesting to see what happens at the NEDRA nationals in Denver in September.

DEFCON is an annual computer security conference, the inexpensive and unruly counterpart to the more expensive corporate Black Hat security conference. From computer security briefings to the toxic barbeque to lock picking contests to a 52-hour competition to turn the electric conference badge into something more by any available means, DEFCON has something for everyone.

My focus is generally attending the briefings on computer security, privacy and civil rights issues, but even that consists of five parallel tracks of concurrent talks, so I only get to see a fraction of what's being presented.

That said, here's my summary of what I learned this year.

Picking the Lock on Your Browser

I trust everyone knows that when you're entering sensitive personal information, like bank account and credit card numbers, into a web page you need to look for the little lock icon so that you know you aren't revealing your info to some malicious criminal. Technically speaking, the lock (along with the https:// in the address bar) guarantees that you are sending that info to the web site you intend (not some malicious forgery) and that the info is being sent in an encrypted form so that even if a criminal is recording all of the data as it is transmitted across the Internet, your private information can't be read.

For the lock to be effective, you need to make sure you entered the correct address into your browser. Getting you to enter an incorrect address is the basis of what is called "phishing." One example of phishing is sending fake email messages that look like they came from your bank, or eBay, or Amazon, etc., which encourage you to follow a link in that email. The link might look like a link to the proper institution, but the actual address is to another site. For example, you might be sent to http://ebay.criminalscammer.com/ which has no association with ebay.com and will instead steal your eBay credentials if you type them into their bogus site. The fake link can be very insidious where it uses some wacky foreign alphabet character that makes the link look like the right web site, something like bankøfamerica.com. You might notice the slash through the "o", but there are other character substitutions where there is no visible difference.

This brings us to the first two rules of Internet safety:

Rule 1: Don't trust a link that you get in email, no matter who it says it's from. Especially don't trust it if it takes you to a bank or commerce web site. Even links to non-commerce sites can be malicious, since there are flaws in browsers that allow a malicious web site to take over your computer, but that's a whole different topic. So, if your best friend in the whole world emails you a link to the funniest photo ever, and you just have to see it, be skeptical and consider verifying the source of the link before clicking it.

Rule 2: Whenever you are about to type anything into a web page that you wouldn't want posted on the bulletin board at the local prison, make sure the link starts with "https://" and that your browser is showing you the lock icon.

That's where we were until early 2008. As long as you always typed in your web addresses, or used bookmarks you created from web addresses you typed in, and you looked for the https:// and the little lock, you were safe.

Then last year, Dan Kaminsky found a problem, but first I have to explain another vulnerability.

There's a step in the web communication process that can be subverted. When you type https://www.yourbank.com/ into your address bar, your browser has to do something like looking up a phone number. Computers on the Internet aren't addressed by name, but instead by a number called an IP address. It's like when you place a phone call, you don't type in someone's name, you enter their phone number. There are special servers on the Internet, called DNS servers, that perform that lookup. So, when you type https://www.yourbank.com/ into the address bar, your computer connects to a DNS server and asks for the correct IP address. That process can be subverted. It's been known for a long time that it's easy to do this locally. So, if you're using the WiFi connection at your local coffee shop, some criminal might also be sipping coffee there and sending your computer fake DNS responses that will send you to their evil server instead of your bank's server.

Rule 3: Don't trust web pages when you're surfing from a public access point. This includes free WiFi at coffee shops and libraries, and also wired Internet connections at hotels, Internet cafes, etc.

That used to be a good rule, until Dan Kaminsky pointed out a problem in the DNS system that has been there for years. There was a flaw in the programming used by DNS servers that made it possible for the bad guys to attack the server and trick it into sending our false information. So, even if you typed in https://www.yourbank.com/, the real DNS server might send you a bogus response that would send your browser to a criminal web server. This is a very bad problem as nearly all of the millions of DNS servers out there were vulnerable. Dan worked closely with the folks who control the majority of the DNS servers to get the flaw fixed on as many servers as possible before announcing the problem to the world.

The careful reader might be thinking that even if someone fakes your DNS responses and sends you to the wrong site when you're trying to do your banking, the https:// and the little lock means that you are connected to the real bank site and your information is encrypted so it can't be read even if it's intercepted. That was true until...

Getting Valid Certificates for Fake Sites

This year at DEFCON, Dan Kaminsky announced another flaw in a major system behind the safe operation of the Internet: it's possible for the bad guys to trick browsers into thinking they have valid certificates for sites they don't own. Certificates are the mathemagical basis of how your browser's little lock icon determines that it's safe to enter and send your private information securely to the party you intend and no one else. The certificate does two things: it proves to your browser that the site it's talking to is the real site for the address in your address bar (which is why it's critical that you have the correct address in your address bar) and it gives your browser the means to establish a secure communication channel to that server which can't be read by anyone else even if they intercept all of your transmitted data. It is widely believed that this security cannot be broken even with a lifetime of effort by an army of supercomputers. And that's still the case, except: the bad guys can get real certificates that allow them to impersonate secure sites.

The trick is somewhat technical, but it is fixable. Hopefully, this flaw will be taken as seriously as the DNS issue was and the several contributing flaws will all get fixed soon. If you're not interested in the technical details of the flaw, you can skip the next paragraph.

When you apply for a certificate from one of the many certificate authorities, you submit a document that states what domain name you want secured. There are multiple formats for encoding this string, including preceding length byte and zero-byte terminated. If you combine both, evil ensues. For example, you can submit a form using the length-byte format for the domain [37]www.yourbank.com[0].criminalscammer.com where [37] represents the length byte covering the entire string and [0] represents a zero byte in the middle of the string. Some certificate authorities will parse this string, pay attention of the length byte, but recognize that the zero-byte isn't a valid character (the digit '0' is not represented by a zero-value byte in order to avoid confusion when using zero-byte terminated strings, see info on ASCII encoding) and parse the string as www.yourbank.com\x00.criminalscammer.com. Their computer decides this is a perfectly reasonable request and contacts the owner of the criminalscammer.com domain to make sure the request came from them. The criminal scammer validates the request and the certificate is granted. The problem comes when a browser gets a bogus DNS reply for www.yourbank.com which directs it to contact the evil server with the wacky certificate. When the browser encounters the zero-byte, it may interpret the wacky domain name differently than the certificate authority and treat that zero-byte as the end of the string and decide the certificate is for www.yourbank.com.

Once this is set up, the victim submits banking info to the evil server and now the bad guys can log into the user's bank account. That's a bad thing.

The good news is that for this to be a problem two things have to occur. First, the user has to get directed to a fake site through a bogus DNS reply, and second the browser has to have the flaw that allows it to see the phony certificate as valid for the legitimate site. Which brings us to:

Rule 4: There is no rule four, follow rules 1 through 3 to avoid getting sent to a counterfeit web site.

We hope that certificate authorities will stop granting these zero-byte certificate requests and browser vendors will fix their code that interprets these fraudulent certificates.

Colleges Throw Out Students' Internet Privacy, Expose to Fraud

Endgrain, an observant student at the University of Southern Maine noticed something odd when he entered a chat room after logging into the university's network: people in the chat room started addressing him by his full name. He did some sleuthing and found out how his university was broadcasting his full name to everyone on the Internet.

When a student at USM logs into the network for the first time, they have to enter their username and password. The network then remembers that machine (by its MAC address) and thereafter lets the user onto the network without entering credentials. It also assigns that student an fully Internet accessible IP address, and maps that IP address to a domain name that includes the student's first and last name. There are a number of problems with this scheme.

First, because the IP address is publically available on the Internet, with no intervening router or firewall, the student computers are open to direct outside attack from anywhere on the Internet.

Second, because the IP address has a full DNS name revealing the student's name, the student is fully exposed to all sorts of privacy attacks. Every web site they visit logs those visits, and hence logs the student's name. Likewise, Google searches are logged and thus a student's search history is exposed to the world. Many other Internet activities expose students to a loss of privacy.

USM isn't the only school doing this to students, at least the practice of assigning DNS names that include each student's full name. According to research done by Endgrain and Dan Kaminsky, some 60 universities are doing this.

Presumably, this destruction of student privacy is done to streamline RIAA lawsuits against students pirating music. With the DNS clearly revealing a student's name, university, and even approximate location on campus, the RIAA can serve up lawsuits without having to go through the bother of getting a court order to find out who is behind an IP address identified as illegally sharing music.

The worst part of this whole thing, at least as USM has implemented it, is that it actually hurts the ability of the RIAA to identify who's behind an IP address. Anyone on the university network can watch traffic and determine which MAC addresses belong to which students. It's then trivial for a malicious student to spoof another student's MAC address then do bad things masked by the DNS name pointing to an innocent student all without ever learning that student's network password. Because of this flaw in how USM allows unsecured logins by MAC address, any student who gets sued by the RIAA has an easy defense: it's wasn't me, someone must have spoofed my MAC address. Guilty students get an easy defense, and innocent students are left to defend themselves in court because of a flawed system.

Everyone loses here. Students lose their anonymity on the Internet and can be identified by anyone, with no need for having a good reason to identify a user or obtain a warrant or court order. The RIAA, and other intellectual property owners, can't actually use the DNS names to identify students since the system is so easy to subvert. Universities look like spineless dorks for outing their students and exposing them to computer attacks.

Students who go to universities that are doing this to their student body should be raising the alarm and forcing a change in policy. We don't want our universities to be teaching students that they have to abandon their first amendment rights for the illusion of corporate convenience.