Range Confidence: Charge Fast, Drive Far, with your Electric Car

By David Herron

Autonomy and electric driving freedom

What we want is Autonomy - the freedom to drive anywhere, anytime. Over the last 100 years we've grown accustomed to that freedom. The American road system is designed around that premise, the open road, driving wherever we want, etc. That ideal may be lost on us during rush hour with jammed highways that have turned into parking lots. But, this ideal is what the car companies sell to us, and it's what we demand our governments build for us.

While going over the steps to learn Range Confidence (Learning Range Confidence), we asked you to think about your Real Needs. If you're like most, your real need is the 40 miles or so a day going to work and back, and some occasional longer trips. That freedom to go anywhere anytime is interesting, but is that your real need?

At the same time we clearly need the flexibility to take trips outside our normal boundaries. We might be at work, the mother-in-law has an emergency illness, and we suddenly need to drive a hundred miles away to take her to a hospital. Can we wait 3 hours for the car to finish charging? Nope. The spouse won't like that, understandably, and it could be a health risk.

While the average person, on an average day, drives less than 40 miles a day, we all will face sudden needs to drive a long distance.

The attributes of Autonomy:

  • Enough driving range for our needs
  • Fast enough refueling for our needs
  • Total driving range per day that satisfies our needs

We gain autonomy not only from a larger battery pack, but from fast charging. So many people have hoped so strongly for long range electric cars to solve the Range Anxiety problem. What really solves Range Anxiety is not the long range, but the fast charging.

Practical example - rescuing the mother-in-law

Returning to the scenario just named, let's get into the details. You're at work, and the mother-in-law is 100 miles away. Perhaps the spouse is already on his/her way, and you need to join them as quickly as possible. Your car has only 20 miles range, and when fully charged it'll only have 80 miles range total. What do you do?

With those limitations your only choice is taking two fast charges along the way from your location to the mother-in-law. The base travel time is over 1 hour, plus another hour for the fast charging. You must already have a good sense of charging station locations so you can just hop in the car and go. The last thing you want is to be fumbling with maps while trying your darnedest to keep the spouse satisfied with your ability to respond to an emergency situation.

Here's where a longer range electric car is useful. You might have arrived at work with 80 miles range indicated, rather than the 20 we suggested above. This would then require only one fast charging session to get to the mother-in-law, shaving 30 minutes off the total travel time. Your spouse will be less unhappy the quicker you arrive.

Practical example - escaping a Hurricane

Thanks to climate change, extreme weather is more common. This means we'll more and more frequently face the need to suddenly pack up the car and the family, and flee our nice wonderful coastal city because a Hurricane is about to make landfall and the authorities have issued a mandatory evacuation notice.

The question is, will you be able to drive away from a life-and-death situation where you absolutely must flee right now.

Pondering this, it seems the primary consideration is the distance you must drive to get to safety. It's unlikely you'll be able to rely on any refueling infrastructure of any sort, either gasoline or electric, because you'll be surrounded by hundreds of thousands of people fleeing the same event. You'll be left driving as far as you can, and then possibly unable to find charging or else face a long line at the charging station. Every refueling station, including gasoline, would be swamped with other refugees also desperate to refuel their car.

Much depends on preparations made by the authorities. Will they arrange sufficient emergency fast charging stations? Will there be enough electrical capacity during the emergency? Will there instead be enough trains or busses to carry everyone to safety?

The 2015 Christmas week saw many reports of long waits at Tesla Supercharger stations because of the crush of Model S drivers all taking road trips. That was just the Christmas traffic. In a real emergency what will we do given the currently inadequate charging infrastructure?

As electric vehicles become mainstream the emergency agencies do need contingency plans to handle emergency electric car refueling.

Actual example of escaping Hurricanes Harvey and Irma, 2017

The 2017 Hurricane season saw at least two back-to-back super-Hurricanes strike the USA. Hurricane Harvey slammed into Houston in late August, causing an immense amount of flooding, damage to oil refining infrastructure, many chemical plants spewing toxic everything into the flood waters, other chemical tanks exploding, and so on. Then a couple weeks later, Hurricane Irma is poised to hit Florida with more energy/strength than Hurricane Andrew in the early 1990's. Earlier in its track, Irma was recorded with wind speed over 185 miles/hr, perhaps the strongest Hurricane ever recorded, and it destroyed most of the habitable structures on several islands.

Officials in Florida have ordered mandatory evacuations ahead of the expected devastation of South Florida. The evacuations mean traffic jams many miles long, and scarce fuel supplies for those unfortunate enough to drive gasoline/diesel-powered vehicles. Going by reports on social media, electric car owners easily find electric car charging.

That is, reports are that Supercharger stations are readily available and it's far easier to get out of Florida with a Tesla than with a gasser vehicle. Lots of gas stations in Florida are either out of gas or there are long 3+ hour waits to fill up. As long as electricity is stable a charging station will work fine, while a gasoline station can easily run out when gasoline demand is high and/or if supply is disrupted. The news is full of reports of panic buying of everything including gasoline.

The only map charging map showing station status -- the ChargePoint map -- indicates the majority of fast charging stations are "green" and therefore available for use.

Another question is whether electricity disruption would render charging stations useless, and therefore make the electric car useful. Reports are that Tesla Supercharger stations in the Houston area stayed in operation after Hurricane Harvey. The ChargePoint map shows all Houston-area charging stations are in operation.

It may be that EV owners of shorter-range electric cars are leaving them at home and driving a gasser to safety instead. There's at least one post from a Nissan Leaf owner describing worry over having left their Leaf at home and wondering whether the car would survive the hurricane. Tesla owners, between a longer driving range and excellent fast charging infrastructure, are justified in feeling confidence to drive their EV far enough to escape the hurricane. A Leaf owner with an 80 mile range and less mature fast charging infrastructure can justifiably worry whether the EV would take them to safety.

Solving the "Long Trip Problem"

We just named off a couple emergency scenarios that will be challenging for an electric car driver. The vast majority of us don't face emergencies every day, or even long range trips every day, but we still need the capability to take long range trips. If only so we gain the most benefit from these cars, by using them for as many trips as possible.

Given that most electric cars are sold for around-town driving, we need to challenge this belief and go about taking our cars on longer trips. Long trips are more feasible in an electric car with more autonomy. Proof? Just look at the Tesla Model S owners gleefully driving coast-coast.

The combination to look for is:

  • An electric car that's affordable for the regular person
  • Enough range -- 150 miles or more range should be sufficient
  • Enough fast charging infrastructure, not just in towns but between major cities

Total Driving Range

In Range Extension & total driving range we defined Total Driving Range as the absolute maximum possible driving distance with a given car in optimum refueling circumstances. If you had the perfect driving terrain, with perfectly spaced recharging stations, what's the furthest you could drive per day?

Is this what we really need? No. Total Driving Range is at best a useful metric to compare cars against each other.

More practically for yourself, your total driving range is what you can achieve, with your car, that you're willing to drive, in your region, with the charging infrastructure available to you.


Range Confidence is Copyright © 2016-17 by David Herron

Autonomy and electric driving freedom

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