Electric Vehicle Options

There are several manufacturers making electric cars that are available today in the United States. The most commonly ones that are currently available as of 2016 are:

Pure Electric

Nissan Leaf

Mitsubishi MiEV

Chevrolet Bolt

BMW i3

Hybrid Electric

Toyota Prius Prime

Chevrolet Volt

Why Tesla?

There is a trifecta of factors that owners of vehicles are looking for. That is range (daily range, extended trip range), appeal (attractiveness, appeal), and capability / usability (passenger and cargo). Of course there is also price, but the vehicle itself has to function for range, usability and capability and be desirable enough that someone wants to spend the money on the vehicle.

Daily Range

The most important is daily range. The vehicle needs to have capabilities to do all your daily tasks without too much trouble. This usually means a larger battery pack that extends beyond what you would normally drive in one day. How much do people drive in a day? Well my job as a real estate agent has me driving about 18,000 miles per year. But that’s not equally distributed to every day of the year. There are some days that I drive 100 miles in a day, possibly 150 miles in a day. But that’s rare. Realistically I think I have driven a maximum of 120 miles, and that’s probably still the rare exception. So if I target a 95% of the time maximum, that would probably be 100 miles.

I can call that the minimum range that I want in a car. I would add a little buffer just in case. Let’s call that 125 miles. So whichever car I get needs to be able to go at least 125 miles on any given day.

Battery size is related to range. The larger the battery pack, the more range. So for the given 125 mile range on any particular day, we need to know how much electricity is used per mile to figure out the minimum battery size needed to cover the 125 mile range I want.

Without factoring in the cold weather we have here in Minnesota, normal watt hours per mile for a Tesla Model S is about 300. So simple math puts 300 * 125 = 37,500 wh, or 37.5 KWH. So a battery size of at least 37.5 kwh will give me the minimum 125 miles that I am looking for.

Cold Weather

Cold weather affects electric car range in a couple ways. The first is that the battery needs to be warmed up to an optimal temperature. The battery heater can take 6kw of power to warm up the battery, and this can take a significant amount of time. With the Tesla, while it’s plugged into shore power (the garage), it can be set to pre-condition the battery (and cabin temp as well) so that it’s warm and ready to go. Doing so won’t affect range because the power to preheat the battery is coming from the house.

The cabin heater is also about 6kw. This can also be set to turn on to pre-heat the cabin while plugged into the house. But there are also seat heaters that use just a couple hundred watts. This means that one can save quite a bit by turning up the seat heaters, and turning down the cabin temp.

With this amount of draw this reduces the effective range of the car. Or stated another way, it increases the watt hour consumption per mile. I have noticed that the consumption is closer to averaging 450 wh/mi in the winter with some of the days being -20 degrees fahrenheit. At -20, I was using close to 800 wh/mile. But that’s only a few days per year. So the majority of the 20 degree days (above zero) was closer to 450 wh/mile. In this case, 450 * 125 = 56,250 wh.

But there is one other factor to take into consideration. On these cold days, the largest amount of power is used in the first 10 to 20 minutes. This is when the car is heating the battery and the cabin. So the 800 wh/mile draw will decrease on longer trips because once the cabin and battery are heated, those heaters are off, or at least minimal.

What these two numbers mean is that a Tesla Model S with a 60 KWH battery will range from about 200 miles on warm days, down to a possible 125 miles on very very cold days.

Extended Range (trips)

The next factor is “can an electric vehicle be my only car?” This would mean that it would have the capability to drive long distances, or be able to recharge quickly, or both. The Tesla addresses both of these issues.

Tesla has built their own supercharger network that is capable of charging cars up around the country. As of December 2016 there were approximately 769 superchargers with more being added throughout the world.  These superchargers are able to charge at 120 KW/h. In practice, the Model S60 can take an 80% charge in 40 minutes, which would charge about 140 rated miles in that 40 minutes.

These superchargers are spaced approximately 115 miles apart from each other. So if you started with a full charge, by the time you reach the first charger, you’ll be at about 40 miles left give or take. Then charging for 20 – 30 minutes would be enough to get to the next charging station. So for every 2 hours of driving, you’ll be taking a 30 minute break to charge.

Compare that to the Chevrolet Bolt. The Bolt has a 60KWh battery as well, and has what they call “fast DC charging.”  This is via a 3rd party network of chargers using a “CCS” charging system, and currently at most provide 50KW/h of charge. That’s less than 1/2 of the speed of the Tesla supercharger. This means for every 120 mile leg, you’d be stopping for a 40 to 60 minute break to charge.

With the Tesla supercharger network, it is possible to drive all the way across the country, stopping every two hours for a 20 to 30 minute break to charge. With the Chevy Bolt, it would also be possible, but you’d be stopping every two hours  for a 45 minute break.

Capability / Usability

Capability is largely determined by what the end user wants to do with the car. For some people, hauling things is a way of life. A Minivan or a Pickup Truck might suit them better. But for a lot of people, the standard full-size sedan can fit their needs. The Tesla Model S is a full-sized hatchback sedan. It can comfortably seat 5 adults, and has an optional 2 jump seats in the hatchback for children. But with 7 people on board, there is almost no storage space left. With 5 people on board, there is quite a bit of space in the rear hatch, and the front trunk. But if it is used as a passenger vehicle, it works just fine. For my purposes, the Tesla Model S works just fine for hauling people around.

Appeal

Appeal almost all personal. Everyone has different tastes and that’s why we have so many choices. To me, the Tesla Model 3 has a sexyness to it, while the Chevrolet Bolt looks like an econo-car. They both will haul 4 or 5 people about 200+ miles, and both are about the same price. One just looks sportier and sleeker than the other. No right or wrong here.