Collect evidence first
Keep photos, records, diagnostic readings and seller explanations.
Pre-purchase risk guides
Used EV battery risk guide library
Practical guides for the used EV questions that cause the most mistakes: range retention, SOH, fast charging, pack impact, flood risk, warranty, commercial use and negotiation.
Risk guide
How much displayed range loss is abnormal?
Displayed range is not SOH, but it is one of the easiest onsite risk signals. Below 80% needs BMS review; below 70% should not be bought on a test drive alone.
Risk guideHow to read SOH and cell voltage delta
SOH reflects capacity-health trend; cell voltage delta reflects consistency risk. One number is not enough: review temperature, SOC, fault codes and test-drive behavior.
Risk guideHow fast-charging history affects risk
Fast charging is not automatically bad, but high share, hot climate, cooling issues and high mileage together should raise the inspection level.
Risk guideHow to inspect battery pack impact
The battery pack sits underneath the car. Minor shield scrapes and structural battery-pack impact are very different risks. Lift the car and inspect edges, mounts, bolts, cooling pipes and high-voltage harnesses.
Risk guideWhy flood and insulation risk need caution
Flood risk in an EV is not just odor or carpets. High-voltage systems, pack sealing, connectors and insulation safety matter. Do not buy a suspected flood car without professional diagnostics.
Risk guideHow to verify EV system warranty transfer
“Still under warranty” must be confirmed through manufacturer systems, warranty documents, contract and service-center explanation. Commercial use, accidents, flooding, modification and unofficial repairs may affect coverage.
Risk guideHow to identify commercial or heavy use
Commercial use does not automatically make a car unbuyable, but it should be valued as heavy-use and checked for mileage intensity, interior wear, charging history, claim records and warranty limits.
Risk guideHow to negotiate or walk away after finding risk
Negotiation is not only about price. Convert risks into conditions: inspect before deposit, define who pays diagnostics, put promises into contract and decide when to walk away.
How to use these guides
Screen risk, then decide diagnostics and negotiation
These guides do not replace diagnostics; they help you ask better onsite questions. When high-voltage safety, flood, pack impact or inspection refusal appears, prioritize walking away.
Then judge limits
Separate negotiable risks, must-recheck risks and walk-away risks.