Battery condition is the single most important — and most expensive — variable in a used EV. Ask for a State of Health (SOH) report: in China, dealers and authorized service centers can read it via the manufacturer diagnostic system. It shows remaining capacity as a percentage of the original. Rule of thumb: above 90% is excellent, 85-90% is acceptable for the price, below 80% needs a serious price cut or battery refurbishment. Also get the battery's full charge and discharge history (次数) — a 3-year-old car with 800 fast-charge cycles has lived a harder life than one with 200. Physically, inspect the battery pack enclosure on a lift for dents, corrosion, or coolant leaks. Check that DC fast charging works during a test charge. Finally, verify the battery is not covered by an open recall or replacement program — this is both a risk and sometimes a free upgrade.

Rust is one of the most underestimated problems in remote buying. Request specific evidence: photos of the underbody, wheel arches, door sills, and around the windshield seal; close-ups of suspension mounting points; and ideally paint thickness readings across panels (factory paint is typically 80-120μm; heavy patches suggest bodywork). Northern Chinese cars may have winter road-salt corrosion; coastal cars can show surface rust on exposed metal. Surface rust on exhaust and bolts is normal—structural rust on frame rails, subframes, or brake lines is a deal-breaker, especially if the car is headed to a humid or coastal market. Have the inspector tap suspicious areas during the video call: flaky or bubbling metal sounds hollow. Walk away if the seller refuses underbody photos.

As rubber seals age, "slight oil seepage (oil stains but no dripping)" is very common in used cars and is not considered a major fault. Our recommendation is: as long as the oil level does not drop abnormally, just clean and monitor it regularly after arrival, without the need to immediately incur high costs to disassemble and replace the seals.