Facts on Charging Your Electric Car Every Night


Should I Charge My Electric Car Every Night

Range anxiety on electric cars is talked about a lot but battery anxiety is another issue. As an electric car owner, I want to do what is best for the health of my lithium-ion battery pack. One main concern is the frequency of charging my EV. 

Should I charge my electric car every night? Does charging daily decrease my battery range over time?

Electric car manufacturers recommend charging your electric car every night. They have charging control algorithms to ensure the battery health is maintained with frequent, convenient, and nightly charging. Tesla, BMW, and Nissan, for example, recommend charging overnight to start the day.

Read on for tips on charging your electric vehicle every night or day while having confidence that your battery will outlast the life of the car.

Why You Should Charge Your Electric Car Every Night

Energy.gov survey found 80% of electric car owners charge at home. Low, stable electricity rates make charging at home the cheapest way to own an electric car. Out of pure convenience, charging at night makes the most sense. 

But, is nightly charging good for your electric vehicle? Nightly charging doesn’t hurt your battery, this is why:

1. Manufacturers Design for Daily Charging

BMW’s official stance is “Always Be Charging”. Tesla and Nissan also recommend charging as is convenient for the owner.

A common concern is the repeated charging of the battery when it is almost full. For example, plugging in at night when your EV’s battery is 90% full already. 

Tesla owners are warry of plugging in when at or above 80%. This is because Tesla gives less fat in its Battery Management System. 

Electric car manufacturers have designed Battery Management Systems to protect and improve the lives of their batteries. All manufacturers keep a reserve at the top and bottom ranges of their batteries.

They will give the driver, for example, 10% to 90% of the battery’s capacity. They will keep the bottom and top percent to prevent the battery from under or over-charging. They recalibrate the display on the dashboard to read 0% to 100% but consider this the virtual battery. 

When I fill up my Nissan Leaf to 100% charge, it is perhaps only at 85%. 

Tesla has changed its virtual battery settings during system upgrades. Owners report getting a boost in range after a system upgrade. This has been credited to Tesla relaxing its upper buffer on the battery charging limit.

Out of electric car manufacturers, Tesla has the least buffer built into its Battery Management System. That is why Tesla has warned in the past to not exceed 80% charge or only infrequently, like long road trips. They trust owners to manage the charge level while other manufacturers maintain larger buffers.

Therefore, while some say that the optimal range to operate an electric car is 20% to 80% they are not considering the virtual battery. Recharge your battery nightly if you require a full charge or out of the habit to plug in every night. 

Because, let’s face it, charging nightly is convenient.

3. The Convenience of Charging Nightly

One finishes their day, parks in the garage, and plugs-in to a normal 110-volt wall socket or a 240-volt home charging station. No more trips to the gas station. This is why many of us buy an electric car, a clean and convenient way to refuel. 

One gains peace of mind knowing their electric car will be fully charged and ready for the next day. 

Americans drive 29.2 miles each day per a AAA study. That is far below the range of electric cars today that can go 150-miles like the Nissan Leaf to over 300-miles like the Model 3 Tesla. 

Yet, out of convenience and perhaps a habit, many electric car owners plug-in every night. Since the manufacturer has designed the Battery Management System to prevent overcharging, charging overnight is part of the design of the electric car.

4. Unexpected Long Trips

Another good reason to charge ever night is the unexpected. Perhaps your work or your lifestyle creates unpredictable travel. Knowing your car is charging every night may help you sleep better in the event you need to do a 50-mile trip the next day.

Always having a 100% charged battery ensures your electric vehicle will be ready for you in the morning, wherever you need to go. 

Consider it a good habit to plugin every night.

Related articles: How to Charge an Electric Car Anywhere You are Driving

5. Charging Limits

If you are concerned with over-charging the battery by plugging it in every night, then consider setting a charging limit on your car. Most electric cars have a built-in feature that enable you to set a charging limit. 

Set the maximum charging limit at 80%. The electric car will stop charging when it reaches 80% during the night. This may be all you need per your morning commute so keeping the battery well within the ideal operating range may help prevent battery degradation.

This may be a good option for Tesla owners you want to ensure they don’t overcharge since they don’t have a large buffer at the top end of their battery. 

With charging apps connected to WiFi-enabled home wall chargers, one can have their maximum charge set at 80%. If they wake up to learn they need a full charge, they can tell the charging app to start charging to 100% while they are in the shower. 

Also, regenerative braking doesn’t activate when the car is at 100%. To save on your brakes and for efficiency, it may be best to charge to less than 100%. 

Nightly Charging Has Not Shown to Significantly Degrade Batteries

I am guilty of overthinking about charging my Nissan Leaf. 

Clickbait headlines, battery expert advice, and lithium-ion battery research provides overly detailed or contradicting guidance on maintaining the health of batteries. Be it your car, laptop, or your smartphone it is confusing to know what is best or worst for your battery pack. 

Worrying about battery healthy is valid. To replace an electric car battery-pack can range between $5,500 for a Nissan Leaf to $16,000 for a Chevy Bolt. As an owner or a potential buyer of this new technology, we want to do what is best for the car’s battery pack.

As electric cars are charged, driven, repeat over the past decade, car manufacturers have learned a lot about the performance and long term health of their lithium-ion batteries. They not only tweak the chemistry to improve long-term battery performance, but they also improve the car’s charging computer and battery cooling system.

Electric car manufacturers are continuing to increase the cycle life – the number of times a battery can be charged and discharged. A Tesla Model 3 has a minimum lifespan of 1,500 charge cycles, translating to 300,000 to 500,000 miles. 

A charge cycle is a complete discharge from 100% to 0% but can occur through numerous charges. Apple Inc. clarifies a charging cycle:

“For instance, you might use 75% of your battery’s capacity one day, then recharge it fully overnight. If you use 25% the next day, you will have discharged a total of 100%, and the two days will add up to one charge cycle.”

Therefore, don’t think that every night that you plug-in your car you are using up one of your 1,500 cycles. 

Several manufacturers offer 8-year/100,000 mile warranties on their batteries. As electric cars age, data has shown this warranty is seldom required. Batteries are outliving the lifespan of the car’s components. 

They make the electric cars idiot-proof when it comes to charging.  Be it charging at home or a public charging station, the car will optimize the charging for convenience and the health of the battery. That is why Tesla is rolling out a one million mile battery

Most car owners are charging their electric cars every night out of convenience and then tracking their real-world battery degradation. Loss of battery range is the real concern with daily or nightly charging. 

Geotab study of 6,300 electric cars found that on average, one can expect a lithium-ion battery to lose 2.3% of its ability to hold a charge each year. 

Tesloop, a Tesla rental service company in California has driven its seven Model 3s, Xs, and Ss over 300,000 miles each, 1,700 miles per month. They have no plans to remove them from service. 

You better believe Tesloop charges their cars every night. 

Related article: Do Electric Cars Lose Range Over Time?

Wireless charging technology is based on nightly charging. Pull your electric car into the garage and head into the home. No unwinding cables to plug-in. The wireless charger will start charging the batteries automatically. 

Go Ahead, Charge Every Night If You Need the Range

As I study electric cars, there is a lot of discussion and uncertainty around what is best for battery operation and maintenance. Research has shown the following impacts the battery’s health.

  1. Time
  2. High temperatures
  3. Operating at a high and low state of charge
  4. High electric current
  5. Usage (energy cycles)

The amount of the impact is still being studied as thousands of electric cars hit the roads and data is being collected. Operating at a high and low state of charge (item 3) is intertwined with charging every night as the battery will be at a high state of charge daily. 

But as mentioned above, manufacturers are tweaking their battery management systems to ensure the way consumers charge their batteries won’t cause range loss or battery degradation with age. No manufacturer wants to have their batteries failing at 100,000 miles, for example. 

Let the debate rage on about it being good or bad to plug-in every night. So far, the data is showing that plugging in nightly won’t have a serious impact on the battery’s long term performance.

We keep our 2017 Nissan Leaf fully charged as it has a 100-mile range. We feel more comfortable knowing the car is ready for whatever we are up to the next day. 

Sleep easy knowing your car is charging and will be ready for you in the morning. If you don’t need a full charge every day, then charge when it is convenient for you. That is the beauty of charging your car at home.

Photo by Ed Harvey on Unsplash

Jordan Fromholz

I'm an electric car owner, enthusiast, and founder of the Plugin Report. As a Chemical Engineer with over 14-years in the energy industry, I've made my passions be renewable energy, batteries, and electric cars. My family lives on Maui where we drive our 2017 Nissan Leaf and share everything there is to know about electric cars.

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