Chill Out With the Fast Charging to Extend the Life of your EV’s Battery

Keep it below 100% most of the time, too

The EV life isn't without its adjustments. Some, like never having to go to the gas station because you can charge at home, are great. Others, like having to plan a road trip like you're traveling from Kansas City to San Francisco in the mid-1800s, are a pain. You might not be aware, but an EV is like the smartphone in your pocket. Eventually, the battery on both will lose some of its capacity. 

The battery residing within an EV might be larger, but it's essentially like the one in your smartphone, laptop, and other electronic devices. While your smartphone providing fewer hours during the day over the course of a few years can be a mild inconvenience, a vehicle losing range over the same amount of time is a much larger headache. But there is a way to make sure that an EV's battery pack with 250 miles of range at the showroom can still cover that amount of distance for years to come. 

EV chassis with battery packs

General Motors

Slow It Down

One of the more important selling points of modern EVs is how quickly they charge. With charge rates above 150 kW, electric vehicle owners are no longer stuck at charging stations for hours on end during a road trip. It brings EVs closer to parity with gas-powered automobiles during pit stops. But that quick charging comes at a price. 

The quicker a battery is recharged, the quicker it begins to degrade. If an EV owner recharges their car only at DC fast-charging stations of Tesla Superchargers, the long-term range of the vehicle will degrade much quicker than if that vehicle was charged slower. 

If you have access to overnight charging at home, that’s where most of your charging should take place. Slow charging is far better for the battery and is typically cheaper than charging at a commercial station. It can be even cheaper if the vehicle is set up to only charge late at night when electricity rates are lower. 

Fast charging an EV

Memorystockphoto / Getty Images

Fast charging should really only be for long trips or days when you’re driving beyond your vehicle’s limits while taking care of chores. Outside of that, charge at home. 

Less Is More 

When you refuel your car, SUV, truck, or motorcycle, you probably fill it all the way up, so you don’t have to head back to the gas station any earlier than needed. You can do the same thing with your EV, but like fast charging, it’s going to hurt you in the long run if you do it all the time. 

There’s a reason your EV dealer tells you to only charge the battery to about 80 percent on a regular basis. Even if the humans you come in contact with during the transaction don’t say anything, the vehicles themselves typically have some sort of warning about battery longevity and the state of charge. Most vehicles will default to charging the vehicle to only 80 or 90 percent. 

“Charging to 100 percent all of the time is not only bad for the battery, but it also wastes a bunch of time.”

Charging to 100 percent all of the time is not only bad for the battery, but it also wastes a bunch of time. As the state of charge increases on a battery, the amount of energy it can accept decreases. For example, if your EV can accept a charge rate of 150-kW, usually around 80 percent state of charge, the rate drops quickly. It has to do with the physics of the battery chemistry, but the best analogy I’ve heard is to imagine there is a 100-seat theatre. When 100 people walk in to fill the room, initially, the seats are filled quickly. There are a lot of options for where to sit. Those last 20 people will have to hunt for those last few chairs and then shimmy their way past people already sitting down. 

Of course, if you’re about to go on a long journey, it’s probably best to charge the EV to 100 percent the night before. Then while on the road, it might also make sense to charge again to 100 percent even though that last 20-percent is going to take more time to fill up. If you charge to 100 percent on occasion, that’s fine. But if you do it all the time, that’s going to degrade the battery quicker, and eventually, you’re going to lose range at a much quicker rate. 

A Little Extra for Later

Car charging in public

Reza Estakhrian / Getty Images

One way to battle the eventual degradation of a battery pack is to put some of the pack aside to replace the dead bits in the future. If you’ve seen a review or the specifications of an EV talk about gross capacity and usable capacity, this is what’s happening. 

Automakers know that even if you treat a battery perfectly by only slow charging it overnight at home and never charging it above 80-percent, it will still eventually lose some of its range at some point in the future. That’s the nature of batteries. Eventually, they’ll lose some of their capacity. 

To ensure that an EV with 250 miles of range at the showroom still has 250 miles of range years in the future, some automakers have set aside capacity. For example, a vehicle might have an 80-kWh capacity pack, but the vehicle can only access 75-kWh on a daily basis. That extra 5-kWh is there to replace cells that wear out over time. It’s like a battery savings account. 

If you’re in the market for an electric car you’re concerned about losing range over the life of your EV, check with the automaker to see if they have some capacity in reserve. Most automakers like Volkswagen, Volvo, and others already do this, but it never hurts to do some research to make sure your next EV is ready for the future. 

And seriously, charge at home at night. It’s cheaper, easier, and your vehicle’s battery will last longer. 

Want to know more about EVs? We have a whole section dedicated to electric vehicles!

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