Cold weather reduces efficiency of all vehicle types, not just EVs. According to FuelEconomy.gov, conventional gasoline vehicles typically have a 20% reduction in fuel economy at 20° F. However, it is often more noticeable with an EV and is especially concerning for all-electric vehicle drivers who need to know they have enough range to reach their travel destinations.
Range Your Electric Vehicle could Lose Due to Cold Weather
Electric vehicles’ performance declines with falling temperatures. Additionally, the driving range fell by 12% at 20 degrees Fahrenheit compared to 75 degrees Fahrenheit, following testing done by the American Automobile Association (AAA) in 2019. When the cabin heating was turned on, this reduction in range rose to 41%.
It is safe to state that cold weather causes your electric vehicle’s range to diminish. Why does this happen, though?
Why Does the Range of Your EV Decrease in the Winter?
We all know, batteries don’t last forever. This is due to other reactions that consume the electron-rich Lithium atoms, degrading battery performance. These reactions occur at different rates at different temperatures.
Therefore, cell manufacturers define a range of temperatures in which batteries can function optimally. For lithium-ion batteries, the discharge temperature is between -4 and 140 degrees Fahrenheit, while the charging range is between 0 and 45 degrees Fahrenheit.
This clearly shows that lithium-ion batteries can discharge at sub-zero temperatures, but charging them at the same is not advised. Also, lithium-ion batteries offer the best discharge performance at room temperatures, and in extreme situations, their performance degrades.
The reason for this degradation is as follows.
When you charge your lithium-ion battery, the charger pulls lithium ions from the cathode, converts them to lithium atoms by adding an electron, and embeds them into the graphite on the cathode.
When the temperature decreases, the lithium atoms don’t intercalate in the graphite; instead, they coat the surface of the anode causing lithium plating. This lithium plating phenomenon converts the otherwise electropositive lithium atoms into an inert metal. Due to this, the number of lithium atoms available for providing free electrons goes down—decreasing the battery’s performance.
Lithium plating increases when a high charging current is used.
On the other hand, when your battery discharges, the lithium ions have to move from the anode to the cathode. During this process, the ions have to move through the electrolyte, but when the temperature decreases, this process slows down as the resistance of the electrolyte increases. This increase in resistance reduces the range your EV offers.
In addition to the factors given above, the battery is responsible for keeping the cabin warm when the weather outside is cold. Due to this, the battery has to run both the vehicle and the heating system, reducing the range further.
Points to consider for efficient EV Experience in the Winter
Now that we have a basic understanding of why the performance of your EV goes down when the temperature goes below sub-zero, we can look at how you can improve your EV experience in winter.
1. Refrain from Fast Charging Your EV during freezing winter
As explained earlier, Lithium plating is a battery’s biggest enemy during cold weather conditions. Not only this, but the phenomenon increases when the charging current is high.
Therefore, it’s advised that you should not fast charge your electric vehicle when the ambient temperature is below freezing
2. Charge Your EV Slowly at Night
If you plan to travel long distances on your EV, it’s best to charge it to the brim at night using level 1 charging. Not only will this provide you with a full charge in the morning, but it also provides a slow charging current that won’t damage the battery.
Not only this, but if you don’t have a heated garage to charge your EV, the slow charging will keep your battery warm, protecting it from cold weather conditions.
3. Be Prepared for Longer Charging Time
As the electrolyte on your battery gets sluggish in colder weather, it takes longer to charge. Therefore, you should be prepared for a longer charging duration while charging in colder weather conditions.
4. Don’t Leave Your Battery Discharged in Cold Weather Conditions
If you are not going to use your vehicle for a long duration, it’s advised to charge it to 70 percent before storing it. Doing this will reduce the reactions which degrade your battery’s health.
In addition to this, you should not leave your vehicle with a low battery percentage at night as it damages your battery’s health.
5. Park Your Vehicle in Heated Spaces
If you have a garage where you can keep your car at night, it’s advised to maintain the ambient temperature between 68 and 72 degrees Fheit. Doing this will reduce the internal reactions that degrade your electric vehicle’s battery, offering better battery performance over a prolonged period.
6. Preheating to 20-30 degrees is “essential”.
Before leaving for work, it’s best to preheat your car slowly while you do your daily chores. Not only would this keep you warm when you go out, but as the car is heated slowly, the battery pack won’t be under much stress when driving.
In addition, you can also connect the charger to your car while you heat it so that the power is drawn from the charger and not the batteries, offering you more range for the day.
7. Keep the Heat on Low
If you are planning to take a road trip in the winter, the heater on your car is the battery’s biggest enemy. Although it keeps you warm, it degrades your battery’s range.
Therefore, rather than running the heater at full throttle, it’s best to use the heated seats and steering wheel to keep your hands and body warm. This could increase your EV range, and you won’t have to charge your vehicle that often.
8. Use Lower Levels of Regenerative Breaking
Most electric vehicles offer different levels of regenerative braking. This enables the EV to charge as its brakes are applied. That said, if you are driving in cold weather conditions, a higher level of regeneration can cause your vehicle to skid on snowy surfaces.
Also, the high level of regenerative braking would supply high currents to the battery, which could damage it due to the colder temperatures.
9. Use Eco Mode
It is best to turn on ECO mode (‘Chill ‘ mode on Tesla) when the weather outside is cold. Doing this would provide better range and decrease the load on your battery – offering better battery health.
10. Usual vehicle checklist
Electric vehicle must be different experience from an ICE, but EVs too have tires which shall have sufficient pressure and in good condition.
EVs can charge on Level 1 charging (plugging into a standard 120V home outlet), which typically takes overnight or longer to charge. Faster Level 2 (240V) charging is also available. Some EVs include DC fast charging capability which can provide an 80% charge in 30-60 minutes under normal conditions. All three types of charging may require more time in cold winter conditions, but this is especially true of DC fast charging.
If you have a garage or carport for your EV that will help keep the battery a bit warmer. Some EVs have battery heaters that turn on in the coldest temperatures (e.g. below 0° F) to prevent permanent battery damage, so it is often prudent to leave your EV plugged in overnight when “polar vortex” air visits your neighborhood – especially if your vehicle is parked outside. Check with your EV dealer or owner’s manual for more information on whether this is a consideration for your vehicle.
If you have an all-electric vehicle, upgrading to a level 2 charger will speed your charging and can also enhance your ability to preheat while plugged-in to preserve driving range.
For DC fast charging in winter, some EVs may have preconditioning systems that warm up the battery when you approach a fast charging stop. For example, if you are on a Tesla road trip including a stop at one of their Supercharger DC fast chargers be sure to use the built-in vehicle navigation system as it will automatically precondition the battery prior to a Supercharging session.
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