With very few exceptions, any battery-operated electronic gadget with a screen today has some way to communicate to the user how full its battery is. Be it a laptop computer, a cellphone or even a personal fitness tracker, battery gauges give us a real-time representation of how full our favorite devices are — and how long it will be before we need to recharge them.
When it comes to electric cars, most automakers provide some form of estimation based on past driving style to give the driver an idea of how far the car will be able to travel before its battery runs flat. Depending on the make and model of the car you own and the uniformity of your driving style and regular routes, that estimation can be reasonably accurate. Indeed, if you happen to own a car like the Tesla Model S — which takes into account terrain, weather and traffic conditions into its range prediction algorithm — you’ll find that your car’s predictions are usually spot on.
But as a trip this weekend from Portland, Oregon to the nearby ski resort of Mount Hood shows, hitting any kind of mountainous terrain in an electric car can seriously alter how your car — and you — view range. Having driven the route before, we knew what lay ahead, but decided to take a camera with us to document just how important knowing your route is when driving a plug-in car in mountainous terrain.
With the early fall weather perfect for a trip to the Timberline lodge on Mount Hood and not a cloud in the sky, we left Transport Evolved’s new offices in Hillsboro on the west side of Portland Oregon with a full charge of our recently-acquired 2013 Nissan LEAF. With the car fully loaded with four people and a picnic in the trunk, we headed east towards Portland along state highway 26 at a comfortable 55 mph. Our starting elevation, for those taking notes, was just shy of 200 feet above sea level.
Passing through Portland — and thus dropping down to a minimum altitude of just ten feet — we climbed back out of Portland on the east side of town, heading ever closer to the majestic volcano that is Mount Hood in the distance.
With 62.4 miles travelled and our LEAF’s ‘guessometer’ reading a predicted 15 miles of range and 2 bars of charge remaining, we decided to stop for a partial quick charge at the CHAdeMO DC quick charger outside the Barlow Trail Roundhouse. With our elevation now some 1420 feet, we knew we’d have some way to climb before reaching Mount Hood’s Timberline lodge, despite being just 17 miles from our destination.
With a little more than ten miles to go to the next DC quick charging station a little further down highway 26 at Mount Hood’s Skibowl West resort, the car’s on-board system was predicting we would arrive with five miles spare. Had we moved beyond Barlow without stopping, we would have all-too-quickly discovered how wrong the car was. Charging our LEAF back up to an indicated 50 percent full, we carried on towards Hood, climbing more quickly than before and arriving at our next stop a full 2,277 feet higher than our previous charging station. Despite covering just 10.5 miles, our range had dramatically dropped back down to two bars and 8 miles of predicted range.
Because the Nissan LEAF — like many other cars — uses its recent energy consumption to predict future range, our LEAF’s range prediction algorithm was particularly pessimistic at this point in our trip. Even with an 98 percent charge, it predicted a range of just 52 miles based on recent driving. At this point, we were just 73 miles from our starting point — but some 3,400 feet higher.
The last part of our climb — a total of 7 miles — was on much slower roads than our previous legs, but climbed up another 2,275 feet to the parking lot at Timberline Ski Lodge. In the winter, this location is only accessible with cars fitted with appropriate winter weather gear, but in the summer the well-kept roads made the climb up towards the summit a pleasurable one.
Upon parking up however, our LEAF had lost a total of 3 bars, and predicted we had just 31 miles of range remaining based on recent driving. With the battery now at 73 percent, anyone seeing the car’s odometer and range prediction without knowing where it was would have easily suffered range anxiety if told we had more than 70 miles to travel back home.
At this point — if you’ll indulge the author a little — I’d like to show you the view from the top of the Magic Mile ski lift, located at around 7,000 feet above sea level and some 1,000 feet higher than the parking lot where we left our LEAF. Ordinarily, this author tries to keep her own political and environmental views under wraps when writing about future car technology. But based on what we saw at the top of Mount Hood, this particular time I’m asking for a free pass.
The photograph above shows you how things looked on Sunday, September 27, 2015, at about 3pm in the afternoon. In the distance — we’d estimate around another mile and a half away and a good 1,000 feet higher up the mountain — several glaciers are visible. As the highest peak in Oregon, Mount Hood has enjoyed an all year-round ski program, with a summer ski school being one of its most famous highlights. This year however, record-low levels of snow means there’s little to see or to ski on, at least at the altitude we were at.
To contrast, we’re going to share a photograph taken in 2002 by a personal friend. While the subject is the same, this 2002 photograph is taken far further down the mountain, before the end of the Magic Mile Ski Lift we took up the mountain. Despite this, the glaciers reach far further down the mountain.
We’ll leave you to draw your own conclusions.
After seeing what was left of the once majestic Mount Hood glaciers, we headed back to the car and on to the task at hand: driving back to Hillsboro. With the route programmed in and our car’s navigation system panicking that we’d run out of charge in a mere 30 miles or so, we pointed our LEAF down the mountain road, opting for the slow and less-known East Pass route down the mountain in order to maximize energy regeneration, and carefully shifting between Eco, B, and D modes to maximize performance.
Just as an electric car can use its motor to recapture kinetic energy as electrical energy upon braking, so too can an electric car high up convert the potential energy of itself at the top of a hill into kinetic energy as it travels down the hill and then into electrical energy to store in its battery pack. The higher the elevation, the more energy that can potentially be stored.
And so it was. Descending the mountain we’d used so much energy to climb, our LEAF slowly began to recapture some of its expended energy. By the time we had rejoined Oregon State Route 26 some 2,400 feet below our starting point, our car’s state of charge had risen to 80 percent.
It carried on rising too, gaining back two full bars and reaching an impressive 88 percent full, representing a fifteen percent increase in state of charge simply by driving down the mountain. Our range prediction had climbed too, peaking at over 120 miles of drivable range based on recent energy consumption.
Of course, by the time our codriver snapped the photograph above showing 119 miles of estimated range, our Nissan LEAF was no-longer complaining about range anxiety and we knew it would be possible to return to base without needing any more rapid charging.
Pulling into our final destination, our LEAF reported having three bars of charge left, 22 miles of estimated range, and a battery charge of 24 percent. We’d travelled 81 miles since leaving our last charging station, climbed a mountain, and then used the wonders of gravity to bring us back home without a spot of range anxiety.
Our point? With the correct planning, our trip to Timberline was a beautiful, stress-free one. We knew where the appropriate charging stations were en-route, knew we could access them to recharge, and knew how to manage our car’s reduce range while ascending the mountain.
Because the on-board range prediction algorithm of the Nissan LEAF is not aware of terrain however, our car wasn’t able to offer any meaningful predictions for the majority of our trip, confused by both the climb up and the climb down.
Had we paid attention to our car we would have been stranded at least once — and possibly have tried to needlessly charge on the way home.
We’ll admit our weekend jaunt is one which few will likely repeat, unless they happen to live near a large mountain range or are planning a family vacation with their electric car far from home. But just as we managed the trip, so too can you — with careful planning.
The first (and most important) thing to note is that you should never leave on such a trip without first knowing where charging stations are along the way. Additionally, when there’s a large upwards elevation change along your route, know that it will dramatically decrease your range, regardless of the car you’re using. If there’s a large downwards elevation change, know that you’ll be able to travel far further than you may ordinarily be capable of driving.
In essence, when you need to climb, prepare to stop more to charge. When you need to descend, enjoy the feeling of going further than you might usually go.
How do you find out just how high you’ll need to climb? For our trip, we used the neat elevation plotter at Doogal.co.uk. Give the tool your starting and ending address, then tell it to find a route between the two points for a full graphical representation of elevation during your planned trip. While it won’t give you the exact figures you need to figure out how much your range will be reduced by, it’s a useful guide to show you how much climbing you’ll need to do.
In our case, climbing 2,200 feet or thereabouts used 25 percent of our car’s battery capacity, but the gradient and the speed you travel at will impact how quickly your battery will deplete on climbing — and how much energy you’ll gain back on descending. For a more accurate and mathematical estimation however, there are tools like the EV Trip Planner, which take into consideration the effect of terrain on your car’s range and energy consumption. In our case, we note that the EV Trip Planner’s interface only offers a beta-level simulation for the Nissan LEAF, which we think is a little over-optimistic based on the route we drove last weekend.
Whatever tool you use however, the message is pretty clear: make sure you understand the impacts of elevation on your next long-distance electric car route — and you’ll find the trip a breeze. Ignore the effects of range, and you could suffer the worst range anxiety of your life.
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