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.

The standard set is: 1. Commercial invoice and sales contract - issued by the exporter; the basis for customs valuation. 2. Packing list - exporter; details the vehicle and any spare parts shipped with it. 3. Bill of lading - issued by the shipping line; your proof of ownership of the cargo. Never pay the full balance before receiving at least a copy of it. 4. Certificate of origin - issued by the China Council for the Promotion of International Trade (CCPIT); some countries require it for preferential duty rates. 5. Export customs declaration - Chinese customs; confirms the car was legally exported. 6. Pre-shipment inspection report - issued by companies like Intertek, SGS or the EAA scheme, if your country mandates it. Ask the exporter for scanned copies of all documents before shipping so you or your broker can verify completeness.

We use two steps: 1. Insert a medical-grade endoscope through the spark plug hole to visually inspect cylinder wall scratches and carbon buildup on the piston top; 2. Extract an engine oil sample to check for large metal debris or emulsification (caused by coolant leakage).