Walk through any car show today and you’ll spot them parked between the restomods and the muscle cars: Teslas, Rivians, the odd Lucid Air. Electric vehicles have become part of car culture, and for owners the big question isn’t horsepower anymore — it’s battery health. Unlike a classic engine you can pop the hood on and eyeball, an EV battery hides its condition behind software. Here’s how to keep tabs on it, and how to know when a problem is beyond a driveway diagnosis.

A little degradation is normal

Every lithium-ion pack loses some capacity over time — that’s just chemistry, and it happens whether you drive a Leaf or a Model Y. The reassuring part: modern EVs degrade slowly. Large real-world studies (like Geotab’s analysis of tens of thousands of EVs) put the average loss at roughly 1.8–2% of capacity per year. So a five-year-old EV holding around 90% of its original range is behaving exactly as it should.

How to check your EV battery health yourself

You don’t need a shop for a basic read. Start with these:

• Dashboard state of health (SoH). Many EVs show battery health or “degradation” in the service menu. Tesla owners can run the in-car battery test; others show estimated range at a full charge.
• Compare real range to original. Charge to 100% occasionally and compare the projected range to the car’s original EPA/WLTP figure. A gap of a few percent is fine.
• Use an app. Tools like Recurrent, or an OBD-II dongle paired with a battery app, pull cell-level data and track SoH over months — far more telling than a single reading.
• Watch your charging. If the car suddenly charges slower, caps at a lower percentage, or range drops sharply over a few weeks, note it.

Warning signs that need a professional

Gradual loss is expected. These are not:

• A sudden drop in range or usable capacity
• Charging faults or the car refusing to fast-charge
• Battery or powertrain warning lights
• Noticeable cell imbalance flagged by a diagnostic app
• Any battery concern after a collision or water exposure

When you see these, it’s time for high-voltage diagnostics from independent EV battery specialists, because this is where an EV is genuinely different from your project car.

Why an EV battery needs the right shop

An EV pack runs at 400V or 800V and is dangerous to work near without training and insulated tooling. A general garage usually isn’t equipped for it, and a dealer will often quote a full pack replacement — easily $6,000–$16,000 — when the real fault is a single module. That’s the gap worth knowing about: a dedicated EV shop can often repair or replace packs at module level, with manufacturer-grade diagnostics, for a fraction of a dealer swap. The trick is finding one that’s actually high-voltage-certified rather than a shop that simply “does some EVs.”

Keep it healthy in the first place

Most of battery care is just habit: avoid leaving the car at 100% for long stretches, lean on the 20–80% range for daily use, don’t rely exclusively on DC fast charging, and park in moderate temperatures when you can. Do that, check your SoH a couple of times a year, and your EV’s battery will likely outlast your interest in the next model.