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Maintaining your EV battery’s “Goldilocks Zone”

Electric vehicles are much simpler than conventionally-fueled vehicles. In fact, that’s one of the best things about them. Part of the reason why EVs are simpler is that they don’t have internal combustion engines. Therefore, they don’t require regular maintenance like oil changes, replacing filters and changing spark plugs.

Electric vehicle powertrains consist of three main parts; the electric motor, the power electronics, and the high-voltage traction battery. Of the three, the battery is by far the most expensive part of the vehicle, and while it doesn’t require traditional maintenance, there are things you can do to maintain your electric car’s battery capacity and increase its lifespan. Other than investing in a JuiceBox EV charger of course.

Tips to protecting your EV battery investment

The battery on an electric car can cost as much as $15,000, so you definitely want to take good care of it so it lasts its expected lifetime. You may ask: How do you “take care” of your electric car’s battery? How long does an electric car battery pack typically last? And what can I do to increase my electric car battery life and avoid battery degradation? The good news is that today’s electric car batteries are high-quality, automotive-grade and are engineered to last. In fact, many auto manufacturers have EV battery warranties for as long as of 8 to 10 years and 100,000 to 150,000 miles.

1. Maintain the ideal state of charge between 40-80%.

Lithium ion batteries last longest when they aren’t always fully charged to 100%, or drained too close to being fully depleted. The manufacturers know this, and they engineer the battery management system (BMS) to ensure that doesn’t happen. So even when you charge your EV to 100% state of charge, the battery is actually only about 90% charged, with the 10% left unused as a “buffer” to prevent overcharging. Still, even with the ~10% buffer, it’s better if you can only power your EV to about 80% - unless of course, you need the extra range for a particular day. In that case, it’s fine to fuel the li-ion batteries all the way to 100% state of charge.

Also, try not to frequently drain your battery below a 5% state of charge. On the occasions that you do, plug the car into a charging station right after you’ve parked, because leaving a nearly-drained battery sit for a long period of time without recharging can permanently damage the cells, shorten the battery life, and eventually contribute to battery degradation. In the occasion that your battery falls below 5%, it is crucial that you keep an EV charging connector in your car that can be used at any charging station. Keeping the battery’s state of charge between 40% and 80% is ideal, but that’s not always possible. Also, if you know you’re not going to be using your plug-in electric vehicle for an extended period, like a couple of weeks, you should leave it between 40% and 80% charged.

2. Keep it cool.

The lithium-ion batteries used in electric cars need to be kept from getting too hot in temperature. Hybrid electric vehicles have thermal management systems to help cool the batteries when they rise in temperature, but they can only do so much. If you live in an area where temperatures frequently exceed 85 degrees F (30C), it’s wise to take some extra steps to protect the battery. Whenever possible, try not to leave the car parked in direct sunlight for long periods of the day, when the temperatures are very high. It’s especially important not to leave a fully-charged battery sitting unprotected for prolonged periods in extreme heat. If you know the car is going to be exposed to high temperatures, don’t charge it past 80% that day, unless you need the extra range.

3. Limit the amount of DC fast charge sessions, especially in hot conditions.

Fast charging on a DC station won’t harm your ion battery as long as you follow a few rules. First, you should limit the number of times you use DC fast chargers. There’s no harm in using fast charging stations a couple times a week, or even a couple of times on the same day when you’re taking a long road trip. However, the combination of frequent DC fast charging in hot ambient temperature settings can accelerate the battery’s loss of capacity. You should try to only use DC fast charge stations when you need to, and use level 2 charging stations for daily re-charging at home.

As you can see, exposing your electric car’s battery to excessive heat for long periods is something you should try to avoid. But how about excessive cold temperatures? Fortunately, cold temperatures don’t harm the battery. The cold will reduce the driving range of your electric car because the chemical reaction inside the battery cells slows down when they are cold, and that limits the amount of energy available. However, as soon as the battery warms up, it’s fine, and there’s no lasting effect from cold conditions. Electric car battery life is not shortened by cold conditions as it can be from excessive heat.

How long does an electric car battery last?

When properly cared for, an electric car battery can last the entire life of the vehicle, estimated to be 15 years. There are also reports of Tesla electric cars with more than 300,000 miles on the original battery, and they are still working fine. If you’re you’re in the market for a new car, electric car battery life shouldn’t be a concern. Especially if you take care of your investment, and follow the simple tips we’ve outlined above.