Category Archives: Electric cars

Six months with Lightning by the numbers

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RC and me getting ready to drive to Montreal in August 2016

Welcome to 2017. It’s now winter here in Massachusetts, and we’ve already had snow and ice. We’re about to return to London for our first training gig of the new year. Yes, I know that we should be aiming for someplace warmer, but I don’t get to choose where business takes me. And frankly, London is delightful to visit any time of year.

I thought New Year’s Day would be a good time to summarize the first six months of life with Lightning, our Tesla S90D. Being a big data guy, I thought I’d do my summary in numbers, so here are my metrics from the final 6 months of 2016:

  • Miles: 5,089: Because of my roughly 50 percent travel schedule, I haven’t been home to drive Lightning as much as I’d hoped. When I am home, I drive it just like I would any other new car. Yes, I leave it in the garage when it’s yukky outside, but that’s just because I don’t want to wash it later.
  • Average energy efficiency: 117 MPGe: For those 5,089 miles, we’ve consumed 289 watts/mile on average. That’s the equivalent of getting 117 miles per gallon if we’d been consuming gasoline, according to the EPA. Given that this car weighs more than 2 tons, that’s pretty amazing fuel efficiency.
  • Supercharger stops: 17: We’ve made 4 trips of 250 miles or more in Lightning since we took delivery: 3 to Orono, ME with David, and one to Montreal, QC with Robert. We’ve been very conservative about keeping at least 20% charge in the battery at all times, so that’s had us stopping more often than absolutely necessary with the 90 kWh battery pack, but the result has been a stress-free driving experience. Superchargers make long distance travel fun and comparable to the travel time spent in a internal combustion car.
  • Service calls: 0: Lightning hasn’t been back to the Tesla service center since we took delivery in June, with the exception of a quick visit to have a leather manufacturing defect repaired. There’s no oil in the car, so we had no need for 1,000 or 5,000 mile oil changes. This car already has had less service than the Mercedes E320 4Matic that it replaced. Lightning’s first return to the service center is currently scheduled for June 2017.
  • Effect on electric bill: negligible: While a full battery “fill-up” should cost about $10 at our electric rates, our electric bills have actually gone down since we started charging our Tesla. One reason we haven’t seen any change is that we normally use scheduled charging to charge the Tesla during the day, when our solar panels are active, effectively giving us free charging. The second reason is not one related to Lightning: this fall has been unusually sunny, resulting in greater solar power generation. Regardless, because our power company doesn’t offer net metering of our solar power, making use of our solar power to power our transportation actually is more cost effective than selling the power back to the grid.

I think the most interesting part of owning Lightning so far is that we use it in the opposite way most people think of using an electric car. When we are driving around town, we alternate between Lightning and my wife’s Acura MDX. But for long distance travel, I vastly prefer taking the Tesla to the Acura. The Tesla is cheaper to drive (free Superchargers versus premium gasoline fill-ups) and the autopilot makes it less tiring to drive for hours on end. Add in the fact that the Tesla is more likely to save our lives in an accident and the choice becomes pretty much a no-brainer.

I’ll update the blog further when I’m back from London and get some time driving Lightning in the inevitable New England snow. Winter isn’t coming; it’s here.

An uneventful 2 Tesla months because I didn’t drive

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Odometer: 4716 miles

I’ve been traveling almost continuously for the last two months, so I haven’t been home to drive Lightning. Carolyn and I did do another 500 mile round-trip to UMaine to visit David in September for Parent’s Weekend, and that was completely uneventful, mostly because the new Bangor Supercharger is now online. Driving to UMaine is now about the same as in a gasoline car because I can Supercharge at my destination as well as along the way.

However, now that I’m back from Mumbai, I’m home for a couple weeks before engaging my final business trip of the year. But now that I’m back and taking some vacation days, I’ve had the opportunity to take Lightning out for errands around town and to enjoy that new Tesla experience all over again.

So here are my thoughts from a few days worth of driving about town.

  • Driving Lightning remains just as fun as it was before. Driving around in silence is blissful, and the crazy acceleration never gets old.
  • Range anxiety is now old news. Driving around in silence is blissful, and the crazy acceleration never gets old.
  • Version 8.0 of the autopilot software was initially squirrelly but has settled down. The new radar-based version 8.0 autopilot seemed to be about the same as the old 7.1 version on highways. However, I drove a couple trips when the new software was released, and it seemed to have a scary predilection for steering toward oncoming traffic on two-lane roads (to be fair, autopilot isn’t recommended for use on two-lane roads, so no harm no foul). However, Tesla has accumulated more auto-pilot radar signatures for those roads, and 8.0 now seems as stable as the old camera-based system.
  • Power consumption is going up as the temperature goes down.Since getting Lightning in June, my power consumption has averaged 286 watts per mile. The last couple of days I’ve been driving around with the temperature in the 30s, and my average power consumption has now more like 295 watts per mile, I assume because heating the car takes more power than cooling it. It will be interesting to see what that number approaches as we get to temps in the teens and single digits.
  • EZPass use is still a mystery.Our EZPass mounted on the windshield works perfectly here in Massachusetts and in Maine. In New Hampshire tollbooths, though, it fails to register. I’ve resigned myself to it just being flakey.

I’m home for a couple weeks, so I hope to collect a few more Tesla experiences to share. Elon has promised that we’ll see version 8.1 of the autopilot software in December, so I’ll certainly write that up when it arrives.

I arrived back in the US of A to find my Tesla asleep

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Odometer: 3690 miles

I’m back from Europe, so now I’ll have a chance to drive Lightning for the next couple of weeks before I leave town for the next 6 weeks.

What surprised me about the recent trip was that Lightning powered itself down about 6 days after I left on September 2. I left my Raspberry Pi logger running, and Lightning stopped responding September 8, despite being plugged into my home charger.

My suspicion is that I have the option, “Conserve Power” enabled on my car, but I had thought that was disabled when the car is plugged into a charger. It seems that this might not be the case. The battery had not lost any charge over the two weeks, so I know it was still awake enough to maintain charge. However, the fact it stopped responding to over the air wakeup requests, despite being on my home WiFi network, is a bit disturbing.

When I got home, I told the car to unlock itself, and the dashboard told me to wait while the systems booted up, so clearly the car had gone into some low power mode. Everything came back online reasonably well, but I did notice that network connectivity was slower than usual and that I’d lost the ability to play TuneIn Internet radio. I did a quick touchscreen reboot (hold both driver’s wheel thumbwheels down for 10 seconds), and everything was back to normal.

Next weekend, we get to put on another 500 miles on Lightning as we head to University of Maine for Parents’ Weekend. This will be aided significantly by the fact that Tesla has now opened its second Supercharger in Maine in Brewer, near Bangor. Not only does this makes trips to University of Maine a piece of cake (Brewer is only about 10 miles from campus), but it also is now the easternmost Supercharger in the US. So now we don’t have to charge to 100% in Augusta to ensure making the roundtrip back to Augusta. Instead, we’ll just charge enough to continue our trip, and then supercharge to 90% or 100% for the ride home Sunday morning.

Wandering the Maine Coastline: Stow-Orono-Mt. Desert Island-Saco-Stow

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Lightning charging in front of the Seawall Motel just after dawn
Odometer: 3520 miles

Sorry that it’s been a while since I updated this blog — I’ve been traveling on business so I haven’t been home to play with Lightning. However, our younger son David departed for University of Maine at Orono, ME last Friday, so we used this trip as an excuse to tour Mt. Desert Island and Acadia National Park in Lightning. The entire trip was roughly 600 miles, and, as one would hope, it went off without a hitch.

This trip was made a lot easier thanks to David and Vickie Lloyd, who run the Seawall Motel. Despite their being off the beaten path in Southwest Harbor instead of the more well-known Bar Harbor on Mt. Desert Island, they installed two Tesla destination chargers connected to a 100A circuit as well as a general purpose EV charger. The result was that we were able to supercharge at the Augusta, ME (so far the only supercharger in Maine), visit the UMaine campus, tour around Bar Harbor, and reach the Seawall with about 150 miles of charge left. We could then charge overnight there up to our full range of 284 miles (see the map below).

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We highly recommend other Tesla owners stay at the Seawall. We plan to return to the Seawall during future trips to Maine. It is open year-round and David and Vickie run a warm, comfortable and clean property. Oh yeah, they like Tesla owners too; Dave noted that he has yet to meet one who didn’t seem like an interesting person.

On Saturday, we walked around the fabulous rocky beaches around the Seawall Motel, toured the island, and worked our way down Route 1 to Saco, ME to visit a relative. We then pressed on to the Seabrook supercharger and headed home. As you can see from the map above, we covered just about 254 miles from our overnight charge at the Seawall until we hit the Seabrook supercharger, arriving with 10% charge. While we had no official backup plan if our energy consumption had run higher than expected, we did observe several public chargers listed on Plugshare.com in places like York, ME and Portsmouth, NH that we could have stopped at if necessary.

Our conclusions from this trip:

  1. Destination chargers are a big win. We wouldn’t have looked at the Seawall Motel if it hadn’t been flagged for us as having a destination charger. Further, if we hadn’t been able to charge at the Seawall, we would have had to hit the Augusta supercharger again on our way home. That would have required us to skip the first 75 miles or so down Route 1 or to have charged at some slower charging station. Having a destination charger allowed us to go where we wanted.
  2. The Bangor supercharger will bring more Teslas to northern Maine attractions. A new supercharger at the Bangor Mall in Brewer ME will be operational in a matter of weeks if not days. That will make Acadia, Bar Harbor, and the Southwest Harbor accessible to more Teslas. In fact, that charger will allow Teslas with 85kWh batteries and up to do round trips to Mt. Katahdin, the most northern point on the Appalachian Trail. Bonus fun fact: When it becomes operational, the Bangor supercharger will be the easternmost supercharger in North America.
  3. Range really isn’t a problem on this car. While we know there are places where no superchargers exist, there aren’t many places with no charging stations at all. Increasingly, we’re feeling like our Tesla is just like our other cars: we just pick up and go, and we will figure out where we will refuel along the way. Planning in advance optimizes the process and will save time, but we are finding that planning on the fly works just fine.

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Boston to Montreal and back

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Odometer: 2,538 miles

Well, Lightning performed flawlessly on our trip to Montreal and back. Unfortunately, my logging program didn’t perform nearly as well. You see, we received data from the car just fine while it was in the US. But when we reached Canada, all of a sudden, the car was no longer visible to the Web. My logger wasn’t really prepared for this eventuality, so it threw and exception and exited.

The other bug I had in my logger was that I vary the polling rate based on whether the car is engaged or not. When the car is parked, I only poll it every 20 minutes. When it is moving, I poll it every minute. What I hadn’t really accounted for though was when it was charging, when it would be nicer to have more granular monitoring of how fast it was charging and at what rate. I’m going to change that for the next go-around.

All that said, here’s an R ggplot of the data that I was able to collect on our trip up to the Canadian border:

Plot

The blue data points show the speed of the car while the red ones show the current draw. The lines are regressions plotted over data point for that metric. You can see the slow polling when the car was charging by those bars showing a few hundred amps going into the car; the current actually varies a lot more dynamically than I’ve shown, but my program just didn’t bother to collect the data.

You can see our long stop-and-go traffic wait at the Canadian border is shown at the end of the graph by what is essentially a period of about half an hour of zero speed and near zero current. You can also see some gaps in the coverage leading up to this point as we passed through areas of Vermont where there wasn’t great cellular coverage.

We can gain a bit more insight by pulling apart the variables into their own graphs using a technique called faceting. Here’s that graph:

Facet plot

The speed graph is about what you’d expect; the first hour was a bit erratic as we escaped Boston area traffic, but as the day wore on, we held a pretty constant 70 mph or so using Autopilot.

What’s more interesting is the current graph: note that it doesn’t map directly to the speed. This feature, of course, is due the fact that the road to Canada is not flat and requires us to traverse the Green Mountains along the way. You can see some pretty big positive battery current spikes that come from the regenerative braking on the descent from some of those mountains.

With these lessons learned, I’ll be updating my logging program for our next trip up to Maine to capture data more reliably. I should have some more data and pretty graphs to post around the end of the month.

One final note: Canadians seem to love Teslas and electric cars in general. Not only did we get thumbs-up salutes from other drivers and curious folks coming over to look at the car, but I was really impressed at the charging stations in Canada. Here’s a photo of the Supercharger in Magog, Quebec:

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As you can see from the photo, Magog isn’t exactly in an urban area, but not only did it sport 8 Supercharger stalls, it had another 8 or so J1772 chargers AND a high-speed CHAdeMO charger. It was most impressive.

Flight plan for our first international road trip

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Route from Stow to Montreal

Route between Stow, MA and Montreal, Quebec, Canada

Odometer: 1840 miles

On Monday, we’re taking Lightning on our first international road trip from Stow, Massachusetts to Montreal, Quebec, where I’m dropping my son to travel to Japan. According to evtripplanner.com, this will be a roughly 312 mile trip each way. Even with Lightning’s 90kWh battery, the trip will require at least one recharging stop, which we’ve currently planned for West Lebanon, New Hampshire.

Supercharger locations with yellow 100-mile range circlesUnlike our prior road trip to Maine, this route really epitomizes Elon Musk’s vision for what an electric car trip should be like. While we have the luxury of a nearly 300 mile range with Lightning, we have no fewer than 3 superchargers along our route AND we have a supercharger available in Montreal when we get there. No one driving a Tesla would have any range anxiety on this route. In fact, as you can see from the circles on the map to the right, any electric car with 100 miles of range would handily make the trip using just Superchargers. And just like in a gasoline car, one could easily do this trip with no planning whatsoever; just point the car in the direction you want to go, and follow the in-car Navigation directions to Superchargers when the planning software tells you to.

One other convenient aspect is that Montreal itself is very EV-friendly. The hotel where we are staying has free parking for electric vehicles, and Montreal boasts a 12-stall Supercharger station and another 2 stalls at one of Canada’s largest Tesla dealerships. For those not in Teslas, Montreal also has an array of J1772 charging stations as shown in the screenshot below. Public EV charging locations in Montreal

We’re charging the battery to 95% capacity today off our solar panels which should give us about 275 miles of range. We will be climbing a bit into the mountains, so we will likely see less than that, but our Supercharger top-up in West Lebanon will easily get us to Montreal with between 50-100 miles of range left. Should we encounter rain or expend too much energy in the mountains, we can always top up again in Burlington, Vermont.

EVtripplanner.com estimates we’ll be driving about 5 hours each way, plus about 40 minutes of charging time, during which we’ll probably get a bite to eat in West Lebanon. I’ll be running my trip logger at home during the trip to record what our actual mileage and charging numbers turn out to be. Our current trip plan estimates we’ll consume about 103 kWh each way. Because our Supercharger use is free, our only vehicle costs for this entire 630 mile trip will be about $5 in tolls to use the Everett Turnpike in New Hampshire.

I’ll update the blog with tweets and photos as we drive up on Monday and back on Tuesday. This should be a fun trip.

Logging Tesla efficiency and performance using the Web API

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Graph of Tesla speed and battery current

Odometer: 1745 miles

One of the cool things about having an intelligent car with a built in LTE connection is the ability to ask it to provide information about itself. Tesla provides both iPhone and Android apps that allow owners to unlock the car, flash the lights, and monitor charging. However, as a Big Data geek and recovering data scientist, I’m more intrigued by recording information about the car so that I can monitor its performance and state over time.

So to begin, a quick shoutout to the developers who have made it possible for owners to monitor their Teslas:

So with all this work as a foundation, as a big data guy, I had to write my own data logger.

Just to be clear, what this API does is not monitor the car itself directly; instead, it communicates with Tesla’s servers that regularly monitor the car. So there’s a level of insulation between user code and the car that I am quite thankful for. I’d really hate to see someone’s buggy code decide to run my car’s stereo system volume up to 11, for example.

My current Tesla data logging program shares a Raspberry pi with a homegrown weather and solar panel monitoring system. Because I started with Rob M.’s example code, it’s written in Python and it’s pretty simple minded. What it does is poll my Tesla every 20 minutes and log its state into a .csv file. If it ever notices the shifter state is not None, it ups the logging rate to every minute until the shifter goes back to None again.

With the data in .csv form, I then can use R and ggplot2 to generate not only line graphs, but to apply a smoothing regression to the data to make it easier to see trends, as shown in the graphic at the top of this post. The blue line in that graph is the car’s speed, while the red line is the battery current, which goes negative when I’m driving the car and goes positive when it is being charged.

This is all pretty rudimentary stuff at present, but I hope to make it more sophisticated as time goes on. At the very least, I’ll have a nice hard baseline of data about driving efficiency and performance when the car was new to compare with as the car ages.

I’ll be driving Lightning to Montreal and back August 8 and 9, so I’ll be particularly interested to see the logs from that 700 mile trip. I’ll share what I learn after I’ve had a chance to analyze the data.

Mass Pike now reads EZ-Pass transponder successfully

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Odometer: 1745 miles

Remember all those problems I was having with my EZ-Pass transponder?

I’ve now had successful reads on 5 different locations on the Mass Pike, so I think I have to declare my new EZ-Pass transponder a success. As you can see in the photo, it’s mounted in the obvious place (the blacked out area of the windshield to the right of the rear view mirror), and I haven’t positioned it upside down or sideways.

I’ll get more opportunities to test its readability when we go to Maine at the end of August, but for now, I have to say that my problem appears to have been more directly related to my 11 year old FastLane transponder than to transponder positioning.

Driving, autopark, and summoning

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Odometer: 1,668

I’m now roughly 6 weeks into my Tesla ownership. I’ve been in Chicago the last week, so I haven’t had much time to drive or blog. However, I have recorded a few observations that I thought would be worth passing on.

  • Turning off “Creep”. When I first started driving the car, I used the default driving settings which make the car creep forward when your foot isn’t on the gas. This emulates the behavior of an ICE car, so it’s familiar to most folks. However, I’ve never really liked this feature, I suspect because I originally learned to drive on a standard transmission where this was not the default. I now have disabled the creep behavior, and the car only moves when I push on the gas pedal. My wife disagrees with me on this (she likes creep), but for me, it makes more sense.
  • Dialing down Summon. The ability to summon Lightning into and out of our garage is one of Tesla’s unique driving features. However, the default settings look for a clearance of around 12 inches from all obstacles, and our garage opening is only about 4 inches wider than the Tesla itself with the mirrors folded out. I’ve now dialed down the sensor clearance to the minimum value (about 8 inches), and I can always successfully summon Lightning out of the garage (as you can see in this video. Getting Lightning to park inside the garage is a little trickier because we have a lip between our driveway and the garage entrance. When we first started, Lightning would abort the maneuver about 50% of the time because of the lip, but nowadays we’re seeing about a 90% success rate, assuming we get it lined up properly to begin.
  • Using Autopark. We spend an afternoon up at Tower Hill Botanical Gardens in Boylston, MA. Autopark indicator It was there that for the first time, I saw a big square P show up on my dash, indicating that Lightning saw an opportunity to autopark perpendicularly. It was pretty freaky at first, especially because you have to have cars on either side of the space for it to enable the function, but once we got the hang of it, we did it three times more. What I found most interesting is that it doesn’t have to get it right the first time; autopark will attempt to cut the wheel to make it into the space, but if it can’t make enough of a turn, it will do exactly what a human would do: it will stop, pull forward, and then back into the space a second time. It’s pretty awesome.

While July has been kind of a bust for Lightning driving, we’ve now planned a couple trips for August:

  1. A trip to Bar Harbor, Maine at the end of August as we drop off David at University of Maine, and
  2. A trip to Montreal, Canada to drop off Robert at the Montreal airport.

While our Maine trip could be a bit challenging (as we noted on our prior trip to UMaine, Maine has but one Supercharger in Augusta, which is more than 100 miles from Bar Harbor), we’re staying overnight at the Seawall Motel on the other side of Mount Desert Island. The Seawall has had the foresight to install 4 EV charging stations including two Tesla chargers and outfitted the lot with 100 amp, 240 volt service. So while we will be staying about 100 miles from the Augusta Supercharger and plan to do some touring around Acadia National Park, we will be able to charge overnight while we sleep and eliminate any concerns about running out of electrons.

Our other trip we’re planning is a quick jaunt up to Montreal, Quebec. While one might think an international trip like this might be more challenging, it’s actually a lot simpler logistically than the Maine trip. Unlike on the Maine trip where we have to plan around a single Supercharging site, we will pass no fewer than 3 Supercharging stations on the Montreal trip: Hookset, NH, West Lebanon, NH, and Burlington, VT. Further, Montreal itself has not one, but two Superchargers in the city itself. So driving to and from Montreal will be a lot like driving an ICE car: we just jump in the car, plan to stop for food and electrons in West Lebanon, and then drive to our destination. It should be a piece of cake.

First trip to the service center

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Odometer: 1,503

As I had planned last week, I brought Lightning to the Dedham, MA service center on Monday to have the rear seat looked at. They took one look and said, “Let us fix that”. So they did repaired the leather while I waited, and Lightning is back to being flawless again. The cost was covered under warranty.

While I was there, I got to watch several other customers come in with other problems. One fellow had a flat tire down on Cape Cod during July 4 weekend and was in the process of getting a new tire and wheel to replace one that the service center loaned him late one night after it had closed. Another woman came in to return the model S that had been loaned her when she had encountered a problem. Despite the fact that they were slammed with new car deliveries (the lot was full of newly delivered cars), the service folks were smiling and bending over backwards to help folks.

One other thing that I observed while waiting for my car was that there didn’t seem to be the wall most dealerships create between the customer and the people who actually work on the cars. Several times, I observed mechanics coming out to talk to customers about what they saw and on occasion, just to chat with the people who had brought their cars in.

I believe that some of this difference in service “feel” is that Tesla’s goal is to build cars that don’t really need service. Electric cars have fewer moving parts than internal combustion cars, so they should be intrinsically more reliable. While that may not yet be the case compared to best-in-class brands such as Lexus and Toyota, Tesla has set itself a lofty goal to eventually better their reliability by about an order of magnitude.

As Tesla’s cars actually approach this goal, then the role of the service center has to be fundamentally different from that of a ICE service center. With traditional ICE cars, the car is sold with a very thin margin, and sometimes at a loss to the dealer. Why do they do that? Because the service center makes up for that loss with highly profitable maintenance visits. That’s why that 15,000 mile checkup at your local car dealer runs $500-$600 instead of the roughly $200 you might spend at a local service station.

Tesla is different because 1) assuming it achieves its reliability goals, Tesla can’t rely on its cars needing service regularly, and 2) because of #1, service appointments have to be great experiences for its customers, which will make them want to bring their cars in whenever something goes amiss. Now, I know some Tesla service centers struggle to achieve this level of service, but based on my sample of one visit to Dedham, it does appear Tesla tries to treat customers more as people than as captive revenue sources. I, for one, appreciate the difference. I’m not the only one either; even though Consumer Reports doesn’t recommend Teslas, Tesla model Ss continue to rate as having the highest consumer satisfaction rating on Consumer Reports.