This answer to the question above, “How much EV range is enough?,” depends on the individual and their needs and habits. I’ll start answering this question with some of my own background owning various electric cars. I’m also tackling the question of how big of a battery one needs. I’ve owned Nissan LEAFs with ranges of 81 miles, 115 miles, and 150 miles. My first Nissan LEAF had a 24 kWh battery. I now own a Tesla Model 3 Long Range with an EPA range rating of 310 miles and a 75 kWh battery. The longest cross-country trip I dared to make with my 2nd and 3rd Nissan LEAFs was 265 miles. Now I routinely make 1500 mile trips with my Model 3 driving 500 miles/day just like I did with my gasmobile.
The electric GMC Hummer pictured above has an EPA range rating of 350 miles from a 200 kW battery. Because of its high weight and poor drag coefficient, its range is lower than that of a Tesla Model S even with a battery twice the size.
The average mileage driven by US car owners is about 40 miles a day, so some experts think an EV range of 200 miles should be adequate for most drivers. I recently met a man who takes this philosophy to the limit. He purchased a cheap, used, 81-mile-rated LEAF with a degraded battery that now has a range of only 40 miles. His commute to work is 10 miles and he was able to get his employer to put in a charger, so the car works fine for his commute. He has another car that he uses if he wants to make longer trips.
However, recently, at the Nephi Supercharger in Utah, I was chatting with a man in his 2021 Tesla Model X and he was complaining about having to charge too often. He lives in Saint George in southern Utah and routinely makes the 310-mile trip to Salt Lake City on I-15 for business. He has to stop to charge twice to make the trip. His Model X has an EPA rating of 358 miles. Why can’t he make the whole trip without charging? I asked him how fast he goes. He said he sets the cruise to 84 mph for the whole trip. The speed limit is 80 mph on most of I-15 on his route, so he’s not going to be pulled over by police. He didn’t seem to be aware that the aerodynamic drag on your car increases with the square of the speed D=Cv2 where v is velocity. If you increase your speed from 75 mph to 85 mph, the drag force increases by 85×85/75×75 = 1.28, or nearly 30%. (Someone, please confirm my math.) Conversely, if you drop your speed by 10 mph or more, in some cases, it could make the difference between making the next Supercharger or getting stranded.
Tesla’s EPA range ratings are for combined city and highway driving. In my experience, you can’t get the Tesla EPA range for highway driving at speeds much more than 60 mph. Nobody wants to travel that slow on Interstate highways in most states, though. Most people will go faster and stop more often. I personally limit my speed to 75 mph in my Model 3, except that I go 80 mph when passing a slower vehicle.
The Tesla Model S and X have 100 kWh batteries. The Tesla Model S EPA range is 405 miles. The Model X is rated for 358 miles on a full charge because it is heavier and is less aerodynamically efficient. Elon Musk says that Tesla’s current lineup of S, 3, X, and Y cars have enough range and he will not be increasing the size of the batteries.
Probably the biggest reason that Elon Musk won’t increase battery sizes in the current lineup is because he can’t get enough batteries. It took 7 years from announcement to delivery of the first Tesla Semis. The Semi requires a huge battery pack. Most people think that the primary reason for the Semi delay was the difficulty in sourcing enough batteries. Another reason for not increasing the size of batteries is weight. Large EV batteries are very heavy, and therefore there is great incentive to limit battery size until battery technology improves.
Factors that Reduce EV Range: The biggie — as explained above — is higher speed. The following environmental factors also come to mind: 1) increase in elevation, 2) headwind, 3) cold temperature, 4) snow and or slush on the road. The following are reasons for lower EV range because of reduced aerodynamic efficiency and additional weight: 1) roof rack, 2) roof box, 3) bike rack, 4) trailer. Obviously, adding skis to the roof rack, gear in the roof box, and bikes on the bike rack will cause further range reduction. Another factor that will reduce EV range is battery degradation. These are all reasons for a bigger battery than your minimum requirements.
Battery Health: Lithium-ion batteries last longer if you limit your state of charge (SoC) to between 20% and 80%. I follow this rule with my Model 3 because the battery is large enough that I have sufficient range for most trips. With my first two LEAF vehicles, I would always charge to 100% because the range was so short that I needed to use the complete SoC range for nearly every trip.
Faster Charging Speed with a Bigger Battery: The latest Tesla V3 Superchargers have a 250 kW maximum rate of charge. When you put the next Supercharger destination into your navigation, your Tesla will precondition your battery for faster charging. If you arrive at the Supercharger with 10% SoC, your car will start charging at a rate of ~220 kW. However, once you reach a 50% SoC, the charging rate will drop to ~100 kW, and as you reach 80% and then 90% SoC, your charging rate will drop to ~50 kW and then go lower. That means: the larger your battery, the faster it will charge. It will take longer to completely charge a bigger battery, but the miles gained per minute in the sweet spot will be greater with the bigger battery.
So, the bottom line is that there are a lot of advantages to a bigger battery. Not only will you have greater inherent range, but your battery will charge faster and you will have a cushion for range reduction due to higher speed as well as environmental, aerodynamic, and battery degradation factors.
Range Reduction due to Bikes on Rack: I generally travel cross country with two big mountain ebikes on my receiver-mounted bike rack (see Figure 2). If you think about it, bikes on a bike rack destroy the aerodynamic efficiency that Tesla worked so hard to achieve. Even with the EPA range rating for my Tesla Model 3 Long Range being at 310 miles, it is a stretch for me to go more than 130 miles between charges carrying the bikes. Fortunately, the spacing of Tesla Superchargers on major highways is generally 70 to 110 miles, so I have had no trouble traveling cross country with bikes on back.
Pulling a Trailer with an EV — Instant Torque: Electric motors have wonderful low-end torque. When you see a 150-car freight train, it may be pulled by as many as 5 diesel locomotives. However, train buffs know that these are really diesel-electric locomotives. The freight locomotives do have a diesel motor, but it only runs an electric generator, which powers the electric traction motors which turn the wheels. Freight locomotives would find it very difficult to start 150 cars from dead stop if they had only diesel engines. I have experienced the equivalent pulling my 2500 lb competition ski boat out of the water with my little Tesla Model 3. I can barely feel the big ski boat come smoothly out of the water and up the steep ramp.
A friend has a huge 5th wheel camper trailer that he pulls with his RAM pickup truck. He chose a Cummins 6-cylinder diesel engine because it has excellent torque for starting his rig and pulling it up steep grades. I think anyone who purchases a Ford F-150 Lightning electric pickup, a Rivian pickup, or the future Tesla Cybertruck will be thrilled by the pulling power even with a heavy trailer and starting from a dead stop or climbing steep grades.
Pulling a Trailer with an EV — Range: However, I think anyone planning to pull a trailer with an EV will be very disappointed with the reduction in range. You are going to love pulling that big boat or trailer 10 miles up the mountain for the weekend. But you are going to hate trying to pull that big boat or trailer cross country. Because of the greatly increased aerodynamic drag, you probably won’t even make it from one Supercharger to the next with anything bigger than the smallest popup trailer. Solution: Airstream has developed a trailer with its own battery that communicates with your vehicle; acceleration and braking are adjusted to match the tow vehicle (see Figure 3).
Pulling a Trailer with an EV — Charging: As I said, for pulling a trailer with an EV, reduction of range is going to be a game stopper for anything but the smallest popup trailer. Let’s say you are pulling that tiny trailer — what happens when you get to a Supercharger? Tesla has come up with many brilliant solutions to engineering its EVs. However, I don’t know how they ever thought that backing up to a Supercharger was a good idea. My Nissan LEAFs were inferior to my Tesla in almost every respect, but they had the charge port in the front of the car, which I loved. I absolutely hate backing up to a Supercharger. It’s extremely difficult with bikes on the back. The electronic distance sensors are blocked by the bikes and I have to have my wife get out and tell me exactly how far to back up. If that’s not bad enough, how could you ever back up to a Supercharger with a trailer on back. A few Superchargers that I have used have one drive-by charging stall. However, there is not enough room to drive by while pulling a trailer. I have seen photographs of Superchargers with drive-by stalls which would work for a vehicle pulling a trailer, but Superchargers like this are very rare at this point.
Please add your expertise about EV range and battery size in the comments section below.
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