Used electric cars are cheap in a way that makes people suspicious. A three or four-year-old EV often sells for thousands less than a comparable gas car, and the reason everyone assumes is the battery: buy one out of warranty and you're one failure away from a five-figure repair.
The fear is understandable. The data doesn't support it in the way most people expect.
Quick answer: Fleet telematics on more than 22,000 EVs put average degradation near 2.3% a year — and closer to 1.8% on newer packs — meaning a typical battery still holds about 83% of capacity at year eight. Full out-of-warranty pack replacements affect a low single-digit share of EVs built since 2016. Priced as a risk, a $11,250 replacement at a 2% chance is about $225 of expected cost, against a used-EV discount that often runs $5,000 or more. The math usually favours buying — but only if you check this specific car's battery health rather than trusting the average.
Batteries don't fail like a lightbulb. They fade gradually, and the curve is gentler than the internet suggests. At 2.3% a year compounding, a 300-mile pack looks like this:
| Age | Capacity Remaining | Range on a 300-mile Pack |
|---|---|---|
| 3 years | 93.3% | 280 miles |
| 5 years | 89.0% | 267 miles |
| 8 years | 83.0% | 249 miles |
| 10 years | 79.2% | 238 miles |
| 12 years | 75.6% | 227 miles |
At that rate the pack doesn't reach the 70% threshold most warranties use until around year fifteen — past the useful life of a lot of cars. Newer chemistries are doing better still, and lithium iron phosphate packs in particular hold up well.
Two things this table doesn't capture. Mileage is a surprisingly weak predictor of battery health; charging history and climate matter more, which is why a 90,000-mile car with gentle charging can be healthier than a 40,000-mile one that lived on DC fast chargers in Phoenix. And frequent high-power fast charging can push degradation toward 3% a year.
Pack prices have fallen hard — from over $400 per kWh in 2012 to roughly $110 by 2025 — and they continue to drop. Installed cost is parts plus $500–2,500 of labour:
| Pack Size | At $111/kWh | At $150/kWh |
|---|---|---|
| 40 kWh | $4,900–6,900 | $6,500–8,500 |
| 60 kWh | $7,200–9,200 | $9,500–11,500 |
| 75 kWh | $8,800–10,800 | $11,800–13,800 |
| 100 kWh | $11,600–13,600 | $15,500–17,500 |
Dealer quotes for a full OEM pack run higher than these figures, often $13,000–16,000 on a long-range Tesla. Remanufactured packs from independent EV specialists typically undercut OEM by 30–50%. And single-module repairs, where only the failed section is replaced, cost a fraction of a full swap and are increasingly available.
The useful question isn't "could the battery fail" — it's "what is that possibility worth in dollars against the discount I'm getting."
Take a used EV at $16,000 against a comparable gas car at $21,000, held five years at 12,000 miles a year:
| Item | Amount |
|---|---|
| Used-EV discount | +$5,000 |
| Fuel savings over 5 years (28 MPG at $3.10 vs $0.16/kWh) | +$3,763 |
| Expected battery risk ($11,250 × 2% failure rate) | −$225 |
| Expected net benefit | +$8,538 |
| Worst case, if replacement actually happens | −$2,487 |
That last row is the honest part. The expected value is strongly positive, but the downside is real and you have to be able to absorb it. If a surprise $11,000 bill would be catastrophic rather than annoying, the average doesn't help you — buy within warranty or don't buy at all.
Compare what an EV and a gas car actually cost you per year in fuel and electricity.
Gas vs EV Savings Calculator →Everything above is an average. Averages don't buy cars.
Battery anxiety crowds out several things that are more likely to cost you money:
Battery costs, warranty terms and degradation data all move quickly. Verify current figures for the specific model and model year you're considering before relying on any of the numbers here.