OFFO
Battery Verification Guide

What to Ask About Battery Health

The battery is the most expensive component in any EV. These questions help you understand what you're actually buying.

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State of Health (SoH) Percentage

Ask for the current SoH reading. Below 80% means noticeably reduced range and potential warranty coverage.

Climate and Charging History

Frequent DC fast charging and extreme heat accelerate degradation. Ask where the car was primarily driven and how it was charged.

Battery Warranty Status

Most EV batteries are warrantied for 8 years / 100K miles. Verify remaining coverage and whether any claims have been filed.

Degradation Curve

Ask for a degradation trend if available. Tools like Recurrent, Geotab, or the OEM app may show historical battery data.

Battery Management System Faults

Request a diagnostic scan for BMS fault codes. Even if the battery seems healthy, stored faults can indicate future problems.

Example Analysis

YELLOW — Proceed with Caution

2022 Tesla Model 3 Long Range · $28,500 · 47,000 mi

Risk Flags

  • No service records provided — request maintenance history before buying
  • Price is 12% below market average for this model and mileage
  • 47k miles is above average for a 2022 — check for fleet or rideshare use

Must-Ask Questions

  • Can you provide the full service history or Carfax report?
  • Was this vehicle ever used for rideshare, rental, or fleet purposes?

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Frequently Asked Questions

What is a normal battery degradation rate for EVs?▾
Most modern EVs lose 2-3% capacity per year under normal conditions. After 5 years, 85-90% SoH is typical. Below 80% is considered significant degradation.
Can I test battery health myself?▾
Some OBD-II readers with EV-specific software (like LeafSpy for Nissan Leaf or ABRP for Tesla) can read battery data. For the most accurate reading, a dealer diagnostic scan is recommended.
Does DC fast charging really damage the battery?▾
Frequent DC fast charging (especially at high ambient temperatures) can accelerate degradation. Occasional use is fine, but an EV that was fast-charged daily may show more wear.

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OFFO provides AI-powered analysis for informational purposes only. Not financial, legal, or automotive advice.