AVILOO’s 500,000-Test Report Says Same-Model EV Battery Health Can Differ by More Than 10 Points

AVILOO says its first Certified EV Battery Report draws on more than 500,000 of the company’s FLASH battery-health tests across 20 EV models conducted from 2022 through 2026.¹² For a used-EV shopper, one practical result is not a single durability ranking: in several battery-pack-specific examples highlighted by AVILOO, reported State of Health varies by more than 10 percentage points among vehicles of the same model at higher mileage.²

That variation matters because a model-level median and the condition of one particular used car answer different questions. AVILOO’s data can describe how batteries in a model group were distributed in its tested sample; the median cannot establish the battery condition of the specific vehicle a buyer is considering.¹²

The same model can contain a wide range of reported battery health

In AVILOO’s highlighted 72.6-kWh Hyundai IONIQ 5 example, the company reports a median State of Health of 92.8% at 150,000 km, with a spread of more than 12 percentage points at that mileage.² For the highlighted 78.8-kWh Tesla Model Y, AVILOO reports a 90.3% median at 150,000 km and variation of roughly 11 percentage points.²

The pattern also appears in two other pack-specific examples. AVILOO reports a 90.6% median at 150,000 km for the highlighted 77-kWh Volkswagen ID.4, with roughly 11 to 12 percentage points of spread at higher mileage. Its highlighted 40-kWh Nissan Leaf ZE1 is reported at an 86.3% median at 150,000 km, with variation reaching 13.5 percentage points.²

Those figures should not be read as universal values for every IONIQ 5, Model Y, ID.4 or Leaf. AVILOO’s broader model charts aggregate multiple battery sizes, while the examples above refer to specific pack sizes.² Because those are different scopes, the pack-specific medians should not be substituted for an all-variant model result.

AVILOO’s State of Health is a proprietary measurement

AVILOO is a commercial battery-diagnostics provider. The company says its FLASH Test uses its own models to calculate battery State of Health rather than simply reproducing a value reported by the vehicle’s battery-management system.³ That is a description of AVILOO’s product and methodology, not an independent validation of its accuracy.

The measurement distinction matters because “State of Health” is not automatically interchangeable across methods. A March 2026 academic preprint analyzing 1,114 EVs across five manufacturers reported that battery-management-system State of Health did not consistently track independently measured capacity across the vehicles it studied.⁴ That study used a different dataset and methodology and does not validate AVILOO’s FLASH system; it instead reinforces the need to identify how a battery-health number was produced before comparing it with another one.

The public materials reviewed for AVILOO’s new report also leave important sampling questions unresolved. The newsroom did not independently audit the raw 500,000-test dataset or AVILOO’s proprietary algorithm, and the reviewed material did not establish how many unique vehicles are represented, whether repeat tests of the same vehicle can appear, or the per-model mix of model years, geographies and battery variants.¹²

For a used-EV buyer, the narrow takeaway is therefore more modest than “this model has X% battery health after Y miles.” AVILOO’s reported distributions show why a fleet or model median cannot tell a buyer the condition of one particular battery.¹² The report does not establish that AVILOO’s test is the only way to answer that vehicle-specific question, nor that its reported State of Health can be substituted directly for an automaker’s battery-management-system value or another diagnostic method.

AVILOO publicly announced the report on September 2 and says it plans to publish the series twice a year.¹

Sources

Footnotes

1. AVILOO Battery Diagnostics — September 2 company update — AVILOO Battery Diagnostics / LinkedIn, Sept. 2, 2026. https://in.linkedin.com/company/aviloo Company-owned announcement establishing the report launch and AVILOO’s claims that the first edition covers 500,000+ tests across 20 EV models and will recur twice yearly. Interested-party source; it does not independently validate the dataset or results. ↩ ↩² ↩³ ↩⁴ ↩⁵

2. “AVILOO Launches World's Largest Independent EV Battery Study” — TimesTech, Sept. 2, 2026. https://timestech.in/aviloo-launches-worlds-largest-independent-ev-battery-study/ Release-like reproduction of AVILOO-described methodology and charts, including the pack-specific IONIQ 5, Model Y, ID.4 and Leaf figures and the use of multiple battery sizes in broader model charts. The material is not an independent audit of AVILOO’s raw data. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

3. “New Battery Certificate — how AVILOO is transforming the used electric vehicle market” — AVILOO, 2025. https://aviloo.com/en-us/blog/new-battery-certificate-how-aviloo-is-transforming-the-used-electric-vehicle-market-2 Company product documentation describing how AVILOO says the FLASH Test calculates State of Health independently of the vehicle’s displayed/BMS value. Interested-party product claim, not independent validation. ↩

4. “Battery health reporting fails independent validation across manufacturers” — Jeongju Park, Kyungkak Kim, Seungho Geum, Junhyung Lee, Hyeongyu Son and Sekyung Han, arXiv preprint submitted March 23, 2026. https://arxiv.org/abs/2603.21592 Reports results from 1,114 EVs across five manufacturers showing that BMS-reported State of Health may diverge from independently measured capacity. This is a separate study and does not validate AVILOO’s methodology. ↩