Unlocking the Secrets of EV Range

In the rapidly evolving world of electric vehicles (EVs), Ford has introduced a computer-generated tool to help take the guesswork out of EV range. The tool determines how far a Ford EV can go based on various factors, including battery size, vehicle trim and options, and drive type. 

 

Ford F-150 Lightning EV. Image courtesy of Ford Motor Company 

 

Anxiety over being caught with a low or empty battery is one of the limiting factors in public acceptance of EVs. The Ford EV range tool aims to provide confidence that the EV has the necessary range to reach its destination. 

 

A Deep Dive Into Determining EV Range

To better understand the factors used to determine EV range, here is a deep dive, exploring how speed, driving styles, temperature, trailer towing, and battery lifespan and configurations will affect the future of electric mobility.

EV range depends upon several critical factors:

• Battery size (kWh): The size of an EV battery pack significantly determines its range. Generally, a higher kilowatt-hour (kWh) rating results in a longer range. For example, the Ford Lightning XLT with a 98 kWh standard battery has an estimated range of 230 miles, while the 131 kWh extended range battery provides an estimated range of 300-320 miles between charges. 
• Weight and cargo: The vehicle's overall weight affects its efficiency and, consequently, its range. The standard-range battery in the Ford Lightning provides a maximum payload capacity of 2,235 pounds. The heavier extended-range battery drops this payload capacity to 1,952 pounds. Loading a lot of heavy cargo will reduce the overall range. A roof-mounted cargo carrier or bicycle rack can add wind resistance and reduce EV range.
• Towing: Towing a trailer affects EV range. Factors include trailer weight, rolling resistance of the trailer tires, and aerodynamic drag created by pulling the trailer through the air. The faster the trailer is towed, the more energy is required, and towing through hills or over mountains draws more energy from the EV traction battery, reducing the overall range. This combination of factors makes it difficult to determine how much towing will diminish the range. Still, test results from various sources suggest the range may be reduced by as much as two-thirds by towing a trailer with an EV.

 

Weather and driving conditions affect EV range. Image used courtesy of City of Aspen, Colorado

 

• Climate and temperature: Extreme temperatures significantly affect EV range. Cold weather reduces efficiency, sometimes by as much as 20-30 percent. Hot weather can lead to battery overheating, reducing the expected battery life. The use of air conditioning requires energy from the traction battery that reduces EV range. There are ways to counter energy use in extreme weather by adjusting cabin temperature and drawing power from the charger while the EV is still plugged in. Pre-cooling the cabin in summer (above 86°F or 30°C) and pre-heating in cold weather (below 39°F or 4°C) is recommended to ensure a comfortable cabin without draining the high-voltage traction battery. Using air conditioning and heat in moderation can help improve EV range. 
• Driving terrain: The terrain, whether flat or hilly, can impact EV range. Long uphill runs will consume energy from the traction battery, some of which will be returned through regenerative braking, while the traction motor acts like a generator and produces electricity stored in the traction battery when traveling downhill. 
• Driving habits: Driving habits, such as acceleration, speed, and braking, also influence EV range. Using cruise control can help reduce energy usage and improve range by reducing the amount of acceleration and deceleration. Braking slowly and smoothly captures more energy through regenerative braking, and avoiding heavily congested areas can increase overall range by reducing stop-and-go driving.

 

Intelligent Range

Ford EVs are equipped with an intelligent range feature that uses cloud-connected software to provide real-time updates on vehicle range. The object is to estimate the travel time for a trip, particularly longer trips where the vehicle must stop charging, and include that charging period into the overall travel time. The Intelligent Range software accounts for the battery state of charge (SOC), the load being carried or towed, data from traffic updates and weather forecasts, and terrain. 

 

Video used courtesy of Ford Motor Company

 

The calculations for range and charge times are based on EPA-estimated range and engineering simulations that consider battery condition and the fact that the rate of charge decreases as a battery nears full capacity.

 

By the Numbers

Going beyond the EPA-estimated range, the Intelligent Range software uses Ford-developed engineering simulations to approximate the expected range and time required to charge the vehicle en route. 

Several factors affect the time it takes to recharge an EV at a public DC fast charger (DCFC). For example, a 150 kW DCFC will charge the standard-range 98 kWh pack in an F-150 Lightning from 15-80 percent in about 36 minutes. The extended range 131 kWh pack can charge 15-80 percent in 41 minutes. 

But here’s the thing: To charge that final bit from 80 to 100 percent can take well over another hour. That’s because lithium-ion batteries degrade much more quickly when charged beyond 80 percent and even more so when DCFC is used. To counteract this, Ford and most other EV makers reduced the charge rate for the final 20 percent. In fact, Ford recommends, when charging at a lower rate at home, to limit the charge to 90 percent for everyday driving and only charge to 100 percent to get full range for a trip. Limiting the charging in this way will help prolong the life of the lithium-ion traction battery. 

To accurately determine how long charging will take when traveling, the Ford algorithm considers not only the current SOC and parameters like load, terrain, and driving style but also the state of health (SOH) of the battery pack to account for its actual capacity based on its charging history. The travel time for two otherwise similar EVs, with different battery SOH levels, could differ slightly, depending on how quickly the traction battery can be charged and the range provided on a charge.