Battery condition is the single biggest value factor in a used EV, and it can be measured — do not accept a verbal "battery is fine" without data. First, ask for a battery health certificate: brands like BYD, NIO, XPeng and Li Auto can generate an official state-of-health report from the VIN, usually within minutes at a dealer or via the brand's app. Look for SOH above 85% for a car under five years old. Second, request a charge-and-discharge test during inspection: the displayed range at 100% charge compared with the original rated range gives a practical health estimate. Third, check battery warranty status. Most Chinese brands offer 8 years or 150,000–200,000 km on the battery pack, and the remaining warranty usually transfers with the car — get this in writing. Fourth, for cars heading to hot climates, confirm the battery cooling system works; overheating is a common killer of battery life. Add a minimum SOH guarantee to your purchase contract so you have recourse if the battery underperforms.

Obtaining precise internal resistance at different SOC levels requires disassembling the battery pack and connecting it to a professional charge-discharge cabinet for several days of cycling tests. This is beyond the scope of non-destructive used car inspections; we only provide real-time estimated internal resistance data based on OBD port readings.

From a technical perspective, China's "National VI B (China VI-b)" is one of the strictest emission standards globally, with limits on carbon monoxide, nitrogen oxides, and particulate matter that are even stricter than some of Europe's Euro VI standards. However, the two are not legally recognized by each other, depending on your country's import regulations.