Quick Facts About How Often You Should Charge Electric Cars
- Most gas cars don’t start every day with a full gas tank, and most electric cars don’t need a full battery each day.
- Keeping an EV charged between 30% and 80% capacity maximizes efficiency and reduces battery stress, which leads to improved longevity.
- Recharging when away from home worries many potential EV drivers, but the number of public charging stations continues to grow.
The question of whether to charge their electric cars every night gets asked by some electric vehicle (EV) drivers who worry persistently about depleting the battery without a charging station nearby.
The short answer to the question is no. Generally, you should not charge your electric car every night because it isn’t necessary for most drivers. In some cases, the practice of charging an electric vehicle every night may shorten the lifespan of the car’s battery pack.
Continue reading for things to know about charging electric car batteries every night.
- You Probably Don’t Drive Far
- Charging Cycles Degrade Batteries
- Always Charging to 100% Isn’t Good
- Charging Stations Are Becoming More Common
You Probably Don’t Drive Far
Figures from the United States Department of Transportation Federal Highway Administration indicate that an average driver logs roughly 14,500 miles annually, or about 280 miles each week.
Environmental Protection Agency data show the longest-range electric cars come close to or exceed that distance on a single charge. Even EVs with shorter battery ranges can cover a good portion of the week when driving the typical 40 miles per day.
Unless you have a frequent long-distance commute, you don’t need to charge your electric car every night. It’s unlikely that any driver of a traditional gas-powered car refills their tank daily, just as it is unnecessary to keep your EV battery topped off.
How Often Should You Charge Your Car?
How often you need to recharge or top off depends on whether you’re traveling away from home and needing to maximize the electric car’s range and your daily commute length.
In general, EV drivers should plan to charge their cars when the battery capacity reaches 30% and then “fill up” to 80% on longer trips. Recharging speed is fastest within those ranges, allowing you to get back on the road sooner. Charge to 100% only when you need to maximize the electric car’s range to cover the distance between charging stations.
Daily charging to replenish energy used for commuting is common among EV drivers using Level 2 and even Level 1 chargers at home. Consistent charging to 100% isn’t necessary and, even with slower chargers, isn’t optimal for long-term battery health.
It’s essential to note that you should always follow the battery charging recommendations found in the car’s user manual.
MORE: Types of Electric Vehicles: EV, BEV, HEV, PHEV
Charging Cycles Degrade Batteries
Lithium-ion battery packs provide power to electric vehicles. While advancements in EV battery technology continue, the repeated cycle of charging and discharging causes lithium-ion batteries to degrade over time.
Reducing the number of effective full cycles and the depth of discharge can help slow the degradation of battery capacity. Some studies indicate five 40%-to-60% cycles or one 0%-to-100% cycle make one effective full cycle. In other words, short discharge cycles are better for lithium-ion batteries. It’s better to do frequent short cycles than fewer long cycles.
If you are familiar with your electric car range, charge the battery when it’s really needed and for the length of time necessary to reach the desired “state of charge.”
Does Frequent Charging Damage an EV Battery?
These basic EV charging tips can help maintain battery health and maximize capacity over time.
- Avoid frequent DC fast charging because high voltage charging can accelerate battery degradation.
- Short charging sessions in the midrange state of charge create less battery stress than a longer charge from deep depletion.
- Some studies show that adding 10% battery capacity — from 60% to 70%, for example — several times each week is better for battery health than a single session charging from 10% to 90%.
- Always follow charging guidance in the owner’s manual.
Always Charging to 100% Isn’t Good
A research team at the University of Michigan developed best practices for extending the life of lithium-ion batteries. One recommendation focuses on a battery’s state of charge (SOC), which is the estimated available power.
The study says that consumers should minimize the time a battery spends at either 100% charge or 0% charge. The reason: Extremely high and low SOC create stress for batteries, shortening their lives.
Electric vehicles have battery management systems to prevent charging and discharging to these extremes. Some are more protective than others. Also, most EV chargers can be set to shut off once the battery reaches the designated SOC, which prevents overcharging.
There may be times when you want or need to charge up your EV to get maximum range. But charging it to the max shouldn’t be done every night. Generally, the battery’s SOC in your electric car should be maintained between 30% and 80% capacity.
Is It OK to Leave an EV Plugged in All the Time?
Keeping an EV plugged in at home overnight with its maximum charge percentage set to 80% can be beneficial in cold and hot weather because preconditioning can happen while the vehicle is attached to the power supply and not deplete the battery’s charge.
MORE: Used Electric Car: What You Need to Know Before You Buy
Charging Stations Are Becoming More Common
Range anxiety is a hurdle many EV owners must overcome to resist the temptation to fully charge their cars every night. Their fear may be real, but so are the many public charging stations throughout the U.S.
A searchable map of electric vehicle charging stations from the U.S. Department of Energy Alternative Fuels Data Center shows more than 66,000 charging stations exist nationwide, a total that continues to grow.
Read Related Articles:
Editor’s Note: This article has been updated since its initial publication.
