EV batteries retain about 90% capacity after 150,000 km, world's largest study finds

Overview

Updated Sep 8

A study of more than 500,000 used electric cars finds most batteries keep about 90% of their original capacity after 150,000 km. The worst performer, the Nissan Leaf, still held 86.7%. None of the 20 models tested had lost more than 10% on average by 50,000 km.

The findings undercut a decade of fears that EV batteries would fail early. They also reveal wide gaps between individual cars of the same model, up to 13.5 percentage points at 150,000 km, which is why independent battery checks matter before buying used.

Why it matters

If battery anxiety fades, used EVs become a safer buy and resale values stabilize, removing a major barrier to mass EV adoption.

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Key Indicators

~90%

Median battery state of health at 150,000 km

Most of the 20 models retained about 90% of original usable capacity at 150,000 km.

500,000+

Independent battery tests analyzed

Tests conducted 2022–2026 across North and South America, Europe, Australia, and Asia.

EV models compared

Median state of health measured at 50,000, 100,000, and 150,000 km for each model.

94%

Best median SoH at 150,000 km

Mercedes-Benz EQA led the field, with Hyundai Ioniq 5 at 93.8% and BMW i4 at 93.6%.

86.67%

Worst median SoH at 150,000 km

Nissan Leaf ZE1 degraded fastest, likely due to a smaller battery and passive cooling.

13.5%

Spread between best and worst same-model cars

At 150,000 km, individual Leaf examples varied by 13.5 percentage points in state of health.

Voices

Curated perspectives — historical figures and your fellow readers.

People Involved

Bernd Berger

Chief executive and co-founder, Aviloo

Leading the firm behind the world's largest used-EV battery study

Organizations Involved

Aviloo

Battery diagnostics company

Published the Certified EV Battery Report, the largest independent used-EV battery study

Austrian firm that measures used electric car battery health with a three-minute OBD diagnostic.

NRMA

Australian motoring organization

Partnered with Aviloo to offer battery health checks in Australia

Australian motoring body that sells independent EV battery checks using Aviloo's diagnostic.

Electrifying, New AutoMotive, and BatteryIQ

EV industry and advocacy groups

Campaigning for mandatory battery health checks on used EVs in the UK

Three UK organizations calling for standardized state-of-health reports on every used EV sold by dealers.

Timeline

January 2022 September 2026

3 events Latest: September 2nd, 2026 · 2 months ago

September 2026
Aviloo publishes 500,000-test battery report
Latest Study Release

Certified EV Battery Report shows most models retain about 90% capacity at 150,000 km.
September 2nd, 2026
August 2026
UK groups demand mandatory battery checks
Regulatory Push

Electrifying, New AutoMotive, and BatteryIQ call for state-of-health reports on every dealer-sold used EV.
August 2026
January 2022
Aviloo begins collecting battery test data
Data Collection

Austrian diagnostics firm starts accumulating independent battery health measurements across global markets.
January 1st, 2022

Scenarios

UK mandates battery health certificates for used EV sales

Possible Resolves by Q2 2027

Discussed by: Electrifying, New AutoMotive, BatteryIQ, and industry campaigners

The UK government adopts mandatory state-of-health checks for dealer-sold used EVs, standardizing the battery report Aviloo and others already offer. This would give buyers a verified number on every car and likely cool fears about hidden degradation.

Used EV prices stabilize as battery confidence spreads

Likely Resolves by End of 2027

Discussed by: Auto industry analysts and used-car platforms

With independent battery data widely available, buyers stop discounting used EVs for feared degradation. Resale values firm up and lease penetration grows as residual values look safer.

Battery guarantees become standard on used EV sales

Possible Resolves by Q2 2028

Discussed by: Dealers, leasing firms, and battery diagnostics providers

Aviloo's €3,000 battery guarantee model spreads. Major used-car platforms and dealer groups bundle state-of-health certificates with warranty protection, making degradation a manageable risk rather than a gamble.

Historical Context

2 moments from history that rhyme with this story — and how they unfolded.

2011–2017

First-generation Nissan Leaf battery degradation (2011–2017)

Early Nissan Leafs used air-cooled, small-capacity batteries with no active thermal management. In hot climates like Arizona, some packs lost 30% or more of their capacity within a few years, forcing Nissan to replace batteries under warranty complaints.

Then

The Leaf's reputation for degradation took root, feeding widespread consumer fear that all EV batteries would die quickly.

Now

Most automakers switched to liquid cooling and larger buffer zones, and later Leaf versions degraded far less.

Why this matters now

The 2026 Aviloo study shows modern EVs, including later Leafs, retain far more capacity than early models, directly addressing the fear those first cars created.

2007–2015

Smartphone lithium-ion battery aging (2007–2015)

Early smartphone batteries swelled, died within a year, and sometimes caught fire. Users learned to expect their phone battery to degrade noticeably within 18 months of purchase.

Then

Replaceable batteries became a selling point, and manufacturers improved charging circuits and chemistry.

Now

Modern phone batteries last years longer, but the 'batteries wear out fast' mindset persisted across all lithium-ion products.

Why this matters now

The smartphone experience trained consumers to expect quick lithium-ion degradation. The new EV data shows automotive-grade battery engineering has moved well past that baseline.