Electric vehicles (EVs) are becoming more popular as people become more aware of their environmental benefits and cost savings over time. One of the most important components of an EV is its battery: it is the primary source of power for the vehicle and makes up 30-40% of an EV’s value.

Because the battery makes up so much of a car’s price, a healthier and better one can be a significant factor in determining resale value. In fact, much like how odometer reading was long used to differentiate between two similar used gas cars, battery health is quickly becoming the differentiator in used electric cars.

But battery health is a lot more than just the miles an electric car has driven. How the car was driven, stored, and charged can all play a role. 

With everything else being equal, an EV with a healthier battery is more desirable than one with a less-healthy battery, and it should get a higher price in a sale or trade in. Here are some reasons why:

1. Increased range: A healthier battery can produce more electricity and can provide more range. This means you can go farther before recharging, which may be more convenient. Multiple cars of the same year, make and model can have batteries that perform differently. Therefore, the vehicle with the healthier battery will command a higher asking price.
2. More range, for longer: Similar to #1, the more range a given EV starts off with during its ownership, the more one can afford to lose to normal, age-related battery degradation over time – all while still retaining a good amount of usability and utility. If you’re shopping for an EV that gets 300 miles of range but you only drive 100 miles a day, you can afford to lose more range than if you bought an EV with a heavily degraded battery. 
3. Longevity: A good, healthy battery is likely to offer more years of service than an unhealthy battery. While battery degradation is typically slow and linear, it accelerates toward the end of the life of the battery, typically a few hundred thousand miles into its life. We have yet to see many EV batteries reach the end of their lifespan, since very few electric cars have been on the road more than 150,000 miles. 
4. Reliability: As batteries degrade, they become less predictable at the bottom end of the State of Charge (SoC) curve. This is partially due to the inconsistency in voltage between individual cells and their ability to uniformly deliver power when needed. So, at low states of charge, your car may think it has enough juice to get you somewhere, and then suddenly displays a much lower charge than expected. This is not an issue with healthy batteries – so good batteries come with a higher price tag. 
5. Eco-friendly appeal: More time before a necessary battery replacement may appeal to people who don’t like the idea of waste, and can command a higher asking price.

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