关键词: 汽车静态耗电异常；保险丝压降测量；新能源汽车；非侵入式诊断；接触电阻补偿

Abstract: To address the issues of circuit disconnection, complex operation, and space constraints in traditional current clamp and series ammeter methods for automotive standby current diagnosis, a non-intrusive measurement method based on fuse voltage drop is proposed by establishing a "voltage drop-resistance-current" mathematical model using Ohm's law. By analyzing the characteristics of fuse circuit body resistance and contact resistance, the equivalent resistance (Raeq≈0.007 5 Ω) is calibrated via the four-wire method, and the standby current calculation formula is derived. Experimental validation is conducted on models such as the BYD Seal 06 DM-i. Results show that this method controls the static current detection error within ±0.5%, improves detection efficiency by 40%, eliminates the risk of circuit damage caused by forceful fuse operation, and reduces module damage risk to 0%. The study provides an efficient and safe technical solution for leakage detection in vehicle electrical systems, which has been standardized in multiple BYD 4S stores and offers a replicable technical path for leakage diagnosis in low-voltage systems of new energy vehicles.

Key words: automotive standby power consumption abnormality; fuse voltage drop measurement; new energy vehicles; non-intrusive diagnosis; contact resistance compensation