October 6, 2022

Why You Shouldn't Charge Your EV To 100%


2 Min. Read

Originally posted October 6, 2022. Updated March 18, 2024.

EV batteries rely on complex chemical reactions to store energy and power your vehicle. Ensuring that these reactions take place in optimal conditions will extend your driving range and preserve your battery’s lifespan. Maintaining your battery charge within a safe threshold can protect this important component. Read on to learn more about safe EV battery charging practices!

Should I charge my EV to 100% full?

No, experts recommend keeping your battery charged between 20 to 80% to reduce stress on your battery. Charging an EV battery to 100% will lead to a reduction in the total usable capacity of the battery. It might not be noticeable at first, but your battery will gradually lose its range as it degrades over time.

Range anxiety is a common issue among EV owners, prompting manufacturers to develop EVs with ranges that exceed 300 miles. While charging your battery to 100% can help alleviate range anxiety, it can put some strain on different elements of your EV battery.

For example, overcharging your battery can result in a loss of active material in the anode and cathode, reducing the total surface that can attract and fix electrons. It can also reduce the number of electrolytes available to facilitate electron movements. Furthermore, a phenomenon known as stoichiometric drift can appear, which indicates an imbalance between the two electrodes.

Learn more about EV Battery Charging Best Practices on the Qmerit Blog.

Understanding EV battery charging

EV batteries use thousands of cells filled with lithium-ion and electrons. Each cell contains a graphite anode and a lithium cathode, respectively acting as positive and negative electrodes. Graphite and lithium molecules continuously exchange electrons that travel through the electrolyte, a liquid medium that facilitates electron exchanges.

When you plug in your EV, the electrons travel from the cathode to the anode to store an electric potential. In contrast, the battery produces power when you drive by moving electrons in the opposite direction, from the negative to the positive electrode.

Other factors that affect EV battery lifespan

Overcharging isn’t the only factor that can lead to battery degradation:

  • DC fast chargers can deliver power outputs ranging from 50 to 350 kW, resulting in charging times of less than two hours. Unfortunately, frequent use of DC fast chargers can accelerate battery degradation.
  • Climate is another important factor. Research suggests that extreme temperatures affect battery chemistry, and the range can drop by 20 to 40% in harsh climates.
  • Cycles, or the frequency at which you charge and discharge your EV battery, can also determine its longevity.

The good news is that EV manufacturers are always looking for ways to build better batteries. While degradation was a significant issue ten years ago, recent EV models come with batteries that are much more resilient. EVs also come with built-in battery management systems designed to protect the battery.

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Charging your EV battery at home with Qmerit

As the largest network of certified EV charger installers in North America, Qmerit is the most trusted EV charger installation partner recommended by automakers, EV charger manufacturers, utilities, businesses, and homeowners alike.

But don’t just take our word for it. Rated #1 in customer satisfaction, Qmerit’s experienced network of certified electricians has installed more than 450,000 EV charging stations in homes and businesses across the U.S. and Canada!

Give us a call at (888) 272-0090 or complete our online EV assessment to find out why we’re North America’s most trusted EV charger installation service provider today!

Author: Greg Sowder

Greg Sowder

President, Qmerit Network