What Kills Range

Range on EVs is affected by pretty much the same things that affect range on gas cars. Speed, tires (rolling resistance and tire weight), wind, rain, temperature extremes, weight of vehicle and load, etc all impact your vehicles range. On this page I will cover these by comparing info I have on a Tesla Model 3 vs gas vehicles.

First Speed...yes, speed kills range.  The force impacting a car as it drives through air is a funtion that is based on speed squared so the drag component on a car increases exponentially based on speed.  What you will notice is that gas cars peak out their range (ie mpg) at 50-55 mph and drop quickly after that. EVs get their best range when going slow and get their rated range at around 65-70 mph and, yes, drop quickly after that.

Wind just impacts the car by roughly the windspeed itself.  A 10 mile headwind will give you a range hit as if you were driving almost 10 mph faster...and a tailwind will increase your range proportionally....not exact as your rolling resistance isnt impacted by wind.  and yes sidewinds also impact airflow around your car, potentially causing more drag on cars with good drag efficiency as sidewinds often cause turbulence where you done want or expect turbulence.

Another thing that impacts range is age. On a gas car mpg starts dropping off  slowly after a few years and by 10 years of driving (ie at around 140k miles the average car mpg range has dropped by 33-35% according to a University of Michigan study.  Teslas on the other hand have around a 5% drop in battery kwh (range) in the first few years and then a pretty gradual and linear drop after that. By the time a Tesla reaches 200,000 miles studies have shown that range loss is less than 12% on average.  There is an interesting summary of this here. This link is about 1 year old so some of the info on the 4680 batteries has matured a bit.

Finally,  two other features in Teslas improve range if set. First is autopilot/fsd...by maintaining a steadier speed range is improved. Similar to mpg savings using cruise control in a gas car.  The second is one pedal driving using hold instead or roll or creep. Hold provides more regeneration capability than the other two settings, so more range. nothing comparable in gas cars. 

One range question people always have in gas cars and EVs is a real simple one...how far can I  really drive if I know my expected range is X?  In the real world, the answer on a long drive won't be X.  On a gas car you usually ignore mpg and just stop and fill up as needed...for one thing the resolution determining mpg while driving is often crude and you often just record miles driven and gas receipts to get an overall idea after the fact. Modern EVs have much finer granularity on a second by second basis on how much energy is expended per distance driven, so more information is made available to the driver and apps that monitor car information. For example, it is possible to see the impact of elevation changes, wind speed, temperature,  aggressive driving, and speeding in a Tesla on a graph while driving or via apps after a trip. For example, I know that in my Tesla I can achieve my rated range while driving 69 mph on a flat highway in 90 degree heat with the AC and FSD on and no wind and no rain to impede the car.  Rated range being basically what my model 3 stealth gets at 240 wh per mile.  That equates to what is considered 100% efficiency for driving in the monitor apps. Do I get that often?  Exactly? No...I tend to speed and enjoy the 0-60 in 3.0 second thing a bit too much and wind and weather can increase or decrease the range. The advantage with a Tesla is that it watches all this for you to ensure you get to a charger safely on a long trip...and for around home with the car charged overnight at home it is imply a non issue.

The following charts are Tesla specific until i track similar info down for gas cars. For now I will just include them without comments. 

For reference, Tesla has listed exactly all the factors that go into predicting the range of a specific vehicle on a specific trip:

• Wind speed & direction

• Elevation/grade

• Traffic speed

• Avg acceleration/deceleration

• Ambient temperature

• Humidity & pressure

• Solar load & cloud cover

• Initial battery %

• Initial battery temperature

• Gross combined vehicle weight

• Rolling resistance

• Aerodynamic drag coefficient

• HVAC consumption

• Vehicle-specific energy consumption (bike rack or similar)

• Battery preconditioning