How to Prevent EV Battery Degradation in the Heat

Electric vehicle manufacturers may offer warranties related to the car’s battery for eight years or 100K miles (whichever comes first). Unfortunately, many issues can impact the longevity of an EV battery. Scorching hot summers or states with high temperatures year-round might pose a problem for the battery life.

Hot temperatures can lead to battery degradation, meaning the battery won’t sustain a charge for the optimum duration. A poor-charging battery results in a less-than-impressive range. Here’s how you can prevent EV battery degradation in the heat, optimize the battery’s longevity, and maximize the range.

Why Does Heat Impact the Battery?

Those hot summer days can be miserable for outdoor activities, but they also can be disastrous for the performance of some vehicles. Electric vehicles have a unique problem when the temperatures soar to scorching degrees. EVs are powered by a motor that gets its energy from the battery; unfortunately, extreme temperatures may wreak havoc with these power sources.

Recurrent reports that when the temperatures start to rise the high heat accelerates the chemical reactions in the battery; these reactions are responsible for the power the battery supplies, but the heat also accelerates a harmful response. Higher temperatures can cause the lithium (which protects the battery) to degrade over time.

This degradation can mean less efficiency. For an EV, this impacts charging and the driving range. Further complicating the situation, Recurrent explains that “The exact way that the heat degradation mechanism works is different for batteries at rest, batteries charging, and batteries being cycled.”

How to Protect the EV

Understanding the temperature’s impact on the degradation of the battery enables car owners to take action. While it might be impossible for drivers to avoid using their cars just because the temperature outside is hot, they can take other precautions to limit their vehicle’s exposure to extreme temperatures.

Recurrent advises against charging a car in the heat. If the outdoor temperature is scorching, wait for the sun to go down and then charge the battery. Store the vehicle in a cooler space, too; a garage offers shade against the hot sun. Some garage spaces also could be air-conditioned.

Consumer Reports tested multiple EV models in different weather conditions; each car was operated in cold, mild, and warm weather (in the 80s). All the models drove the furthest on a charge in the warmer weather conditions. The cold weather drained the battery life, though.

In some areas, even 85-degree weather might be a mild summer day. In parts of the Midwest, it isn’t uncommon for July or August temperatures to hit the mid-90s or even soar up to 100 degrees. Unfortunately, Consumer Reports didn’t test the EV range against excessive heat.

Other Issues Impacting Range and Battery Life

Electric vehicles are unique in that they don’t require standard fuel. Their power is derived from electricity, and the plug that charges the battery also allows these vehicles to be less expensive to operate. Car shoppers who are researching electric vehicles will likely review the range of the cars they are considering.

The range of an EV denotes how far the car can drive on a fully charged battery. Every EV publishes its estimated range. According to Car and Driver, the electric vehicles with the longest estimated range are:

• Lucid Air Grand Touring (estimated range of 516 miles)
• Tesla Model S (estimated range of 405 miles)
• Hyundai Ioniq 6 (estimated range of 361 miles)
• Tesla Model 3 (estimated range of 358 miles)
• Mercedes-Benz EQS (estimated range of 350 miles)

These are the top limits of each vehicle’s range. What EV owners will discover, though, is that the estimated range can be decreased for many reasons. Driving habits, the weather, and even the slope of the street can decrease the estimated range.

Driving fast, going uphill, using the heat or the air conditioner, and towing all can lead to a decrease in the estimated range. While a standard internal combustion engine vehicle will have decreased fuel efficiency when the air conditioner is used in summer, using the heat typically doesn’t impact the gas mileage. With a standard engine, the heat doesn’t require additional power; instead, the heat from the engine is pulled into the cabin of the car to warm up the air.

In contrast, an EV needs battery power for almost everything used to operate the vehicle. The heat requires battery power, cooling the car uses power, driving fast also uses additional power, and the list goes on.

For those road-tripping in their EV, the outdoor temperature also decreases the range. Again, extreme heat can lead to the degradation of the battery. Extreme cold temperatures require more energy from the battery.

 How Long Should the Battery Last?

The longevity of an EV battery might depend on the manufacturer and the driving habits of the owner, too. Thankfully, every manufacturer offers a warranty that protects the battery of the vehicle. These warranties usually extend eight years or until the car’s odometer hits 100K miles.

For EV owners who use their car for long commutes, the warranty might expire quickly. Once the battery warranty expires, any battery issues may become a problem for the car owner. Unfortunately, replacing a battery for an EV can be a costly investment. Some EV battery replacements are so expensive that purchasing a new car is the cheaper option.

Adopt Good Charging Habits for an EV

Charging habits also can impact the longevity of an EV battery. J.D. Power advises EV owners to mind the “80/20 rule.” The site explains that the battery shouldn’t be charged beyond 80 percent and the owner shouldn’t let the battery run down to less than 20 percent before charging it.

Overcharging the battery and letting the battery deplete too low can impact the battery’s longevity over time. Proper charging habits can help maximize the battery life and get the most mileage out of a full charge.

Before embarking on a long trip, EV owners may want to plan ahead by plotting out charging stations along their route. Letting the battery deplete too low could mean the driver doesn’t have the battery life necessary to make it to a charging station. Drivers could find that their range is lower than anticipated if they need to use the heat or the air conditioning. A 30 percent battery life could diminish quicker than the driver anticipates.

Electric vehicles provide a battery life indicator on the infotainment screen to help drivers monitor their charge. This data can help ensure that drivers find a charging station before the battery depletes too low.

Charging Options

Buying a new electric vehicle can be an expensive purchase. Unfortunately, the options for affordable EVs are dwindling; Chevrolet recently announced that it would not bring back its affordable Bolt EV and Bolt EUV models. These two vehicles were the least expensive EVs on the market.

Instead, buyers might focus on models that offer the longest range for the money. Tesla offers several models with long driving ranges. The vehicles with the longest estimated ranges are more expensive. As of publication; the Lucid Air Grand Touring starts at $138,000; the Tesla Model S is priced at $88,490. However, the Hyundai Ioniq 6 is priced much more affordable; it starts at $45,500.

Buyers could consider pre-owned or used electric vehicles, but they might want to research the age and mileage of these vehicles. Battery warranties eventually expire, and buyers want to be sure that the battery warranty is still applicable (and transferrable). CapitalOne advises buyers to ‘read the fine print’ related to warranties to be certain that the battery warranty is transferable.

Compared to a newer EV, an older model might lag in range. While the battery warranty could be in effect (and is transferable), the battery itself might not hold the charge it once did as a new model. Every vehicle is different, though. When buying a used car, consumers can request a third-party inspection to determine if there are any underlying issues. With a used EV, buyers might ask the mechanic to check the battery.

Beware of Temperature Extremes When Owning an EV

Whether buyers choose a new model electric vehicle or a used or pre-owned EV, they may need to remember that the battery can be impacted by severe cold and heat. Driving in extreme cold temperatures (especially short distances) can lower the estimated range. However, extreme heat can exacerbate the chemical reaction in the battery; this speeds up the degradation of the battery and decreases its longevity.

During hot summer days, EV owners can wait to charge their cars during the evening hours; most owners charge their cars overnight to ensure the vehicle is fully charged for the morning commute. In addition, EV owners should try to park their vehicles in the shade (or in a garage) to limit the battery’s exposure to high temperatures.