EV Battery Health Basics Your Car Dealership Should Know
EV Battery Health Basics Your Car Dealership Should Know
Technical Input By
Written by
Andrew Garberson
Research
July 21, 2025
Electric vehicle batteries are holding up much better than most people expected. That’s great news for every EV owner and used EV shopper.
But up to half of a vehicle’s value is tied up in the battery so it's still a major consideration when you're looking to invest in a car. It’s essential to buy from car dealerships that understand EV battery health basics.
The right dealership won’t dodge your battery questions or give vague answers about range. They’ll know how EV batteries work, how they degrade, and how to show you real data — not just guesses.
How can you know if your sales rep is EV-savvy or stuck in the gas-powered past? Start with this: ask about battery health.
First: What Is Battery Health, Anyway?
The term battery health can mean a lot of things but, for this purpose, let’s think of it as how much of the original range a vehicle can still travel.
You’ll also see it referred to as State of Health (SoH) and battery degradation. The easiest way to explain it: Compare the battery’s original capacity in kilowatt-hours (kWh) to what it can hold now. Less capacity = less energy = less range.
Caption: Batteries follow an “S-curve” of degradation: A quick dip early on as the battery forms a protective SEI layer, years of slow, stable wear of 1–2% per year, a sharper decline way down the road, when the battery finally starts to wear out.
There’s also a sneakier kind of aging called power fade. That’s when internal resistance builds up, making it harder for energy to flow, even if the battery’s still technically "full." The most common symptom of power fade is slower acceleration and performance.
What Causes EV Battery Degradation?
Batteries don’t last forever, but they also don’t degrade like your iPhone. Recurrent has tracked over 250 million real-world EV miles, and here’s the big takeaway: most batteries are in great shape.
In fact, only 2.5% of batteries have been replaced. So what are the main enemies of battery health?
1. Heat
Excess heat speeds up chemical reactions that degrade the battery. That means EVs in hot climates need strong thermal management systems to keep the battery cool. Fortunately, most modern ones come with these systems standard.
2. Extreme States of Charge
Both topping off to 100% and running down to 0% can hurt battery health if done frequently. It’s best to keep the charge somewhere between 20-80% — especially when leaving your car for a while.
3. Fast Charging
Fast charging gets a bad rap because it used very high voltage and creates a lot of heat. Over time, these conditions can cause a kind of internal scarring that reduces range and slows down charging.
4. Time + Use
Even when not in use, batteries age — this is called calendar aging. This sort of aging is inevitable, but certain things can make it worse.
Questions to Ask about Batteries and Range
- “What is the realistic range today and after 3 years?” Range is not a static number (e.g. EPA) so look for answers that include seasonal changes and the S-curve (above) then gradual fluctuations of 1-2% per year.
- “How long do EV batteries last?” Only 2.5% of EV batteries have been replaced, so we don’t know the exact answer yet, but 10 to 20 years is a conservative estimate.
- “How long is the manufacturer’s battery warranty?” Warranties range from 8 to 10 years and/or 100,000 to 175,000 miles. Make sure your salesperson can tell you how much more warranty a certain car has, and verify that it transfers.
Tips for Dealership Sales Teams
- Know the basics. Understand things like the difference between battery capacity and power fade.
- Talk in real-world terms. Shoppers care about range and reliability, not chemistry.
- Make it simple. Affordable EV retailing products exist to explain range, batteries and charging in simple, data-backed ways.
Electric vehicles are here to stay, and battery health is a fundamental piece of vehicle aging and prices. Dealerships that understand and explain EV battery basics will win trust and keep shoppers coming back.