The battery warranty policy for BMW's 48V mild hybrid system usually aligns with the vehicle's basic warranty period. Currently, mainstream BMW models such as the M340 Sedan and 430i Convertible have a basic warranty of 48 months or 80,000 kilometres (whichever comes first), while core hybrid components like the battery may enjoy a longer separate guarantee. Specifically for the 48V mild hybrid battery, its warranty coverage generally includes manufacturing defects and performance degradation, but it is subject to the official *Owner's Manual* or the latest policies from the dealer. For example, some BMW plug-in hybrid models (such as the 530e) offer a 6-year or 100,000-kilometre warranty for their battery modules. As a transitional technology, the 48V mild hybrid system may have a slightly shorter battery design life and warranty terms compared to high-voltage batteries, but they are usually still significantly longer than those of ordinary fuel vehicle components. However, due to the lower voltage of the 48V system, its battery structure may differ from that of high-voltage batteries.
