Largest independent study finds most EV batteries lose less than 10% capacity by 50,000 km

# What the study measured Austrian diagnostics firm AVILOO compiled over 500,000 independent battery State of Health (SoH) tests gathered between 2022 and 2026 across North and South America, Asia, Australia and Europe. The dataset covers 20 popular EV models and reports lower bound, median and upper bound SoH values at 50,000 km. SoH is a percentage of original usable capacity: 80% SoH means 80% of the original maximum range remains.

# Main findings Overall, batteries held up better than many consumers expect. None of the 20 models showed a median SoH decline greater than 10% at 50,000 km. Top median SoH scores were: Hyundai Ioniq 5 at 97.13%, Mercedes EQA at 96.56% and Hyundai Kona at 96.27%. At the lower end, Nissan Leaf (ZE1) and Renault Zoe recorded medians near 91%.

The study also highlights two important patterns. First, models with smaller battery packs generally showed greater degradation. Smaller packs need more frequent charging cycles, which accelerates wear. Second, there's substantial variation between individual cars of the same model: examples of one model can span several percentage points of SoH at the same mileage.

# Specific model notes

• Mercedes EQA and Hyundai Kona: both among the top performers by median SoH.
• Tesla Model Y and Model 3: medians (94.42% and 93.77% respectively) were lower than many large-battery rivals, despite Tesla's published longevity claims. Tesla acknowledged drivers often see an initial drop in SoH during the first few thousand miles before a flatter decline.

# What drives battery ageing in this dataset The dataset points to two practical drivers:

• Battery capacity size: larger packs need fewer full or partial charge cycles for the same kilometres, which reduces cumulative wear over the same mileage.
• Charging frequency and patterns: more frequent charging cycles increase wear. Fast charging practices, depth-of-discharge extremes, and high charge states all affect SoH, though the study's public summary emphasises cycle frequency and pack size.

# Implications for buyers and owners When assessing used EVs, model-level medians are a helpful starting point but not definitive. Because individual cars of the same model can differ substantially, always check an individual vehicle's measured SoH. For ownership practices, moderating charge frequency (where feasible), avoiding repeated deep discharges and limiting time spent at 100% charge are pragmatic ways to reduce long-term wear.

# Bottom line This large-scale dataset reduces the uncertainty around EV battery longevity: batteries generally retain most of their usable capacity through the first 50,000 km, but model choice, battery size and real-world charging behaviour affect how much capacity remains for any specific car.