Used BMW i4 Alternator

The BMW i4 launched in the UK in 2021 as a first-generation model, based on the G26 platform, and as of 2025 remains within that first generation with no full generational change yet announced. This is important because alternator fitment questions are really about whether the electrical architecture and engine (or in this case, drive unit) matches between cars. Always confirm against your exact registration with the breaker before purchasing.

The BMW i4 is a fully electric vehicle and does not use a conventional alternator in the way a petrol or diesel car does; instead it uses a DC-DC converter to charge the 12V auxiliary battery from the high-voltage system. If you need this component, the part number and compatibility can vary with production changes within the G26 generation, so you should confirm against your specific registration and build date with the breaker rather than assuming year-to-year interchange.

Trim level alone does not determine fitment for mechanical or electrical drivetrain components like the DC-DC converter; what matters is the specific drive unit variant and output level, which differ between the eDrive35, eDrive40, and M50 models. The M50 in particular uses a dual-motor setup which is a fundamentally different drivetrain to the single-motor eDrive35 and eDrive40, so parts from an M50 are unlikely to cross-fit. Confirm the exact drive unit code and configuration with the breaker against your registration before ordering.

BMW does share electrical components across platforms in some cases, but the i4 (G26), iX (I20), and i7 (G70) are distinct platforms with different high-voltage architectures and packaging, so fitment is not straightforward. You should not assume cross-model compatibility and instead confirm against your registration with the breaker who can check part numbers directly.

Strictly speaking the BMW i4 does not have a traditional alternator as it is a fully electric car, but some breakers and listings use the term loosely to refer to the DC-DC converter, which is the component that performs the equivalent function of keeping the 12V system charged. Searching for 'DC-DC converter' as well as 'alternator' will help you find more accurate listings, and you should confirm with the breaker that the part number matches your specific vehicle registration.

BMW does make running production changes to components like DC-DC converters that may not align with a simple model year boundary, and these ancillary or mounting changes are not always publicly documented in detail. Because of this, whether a specific used unit crosses a production-date boundary and fits your car is something you must confirm with the breaker against your exact registration rather than assuming compatibility based on year alone.