Second Hand BMW i3 Battery

The BMW i3 was produced from 2013, with a significant update in 2017 when BMW increased the battery capacity from 33kWh to 94Ah (approximately 42kWh), and a further range increase followed in 2018 with the 120Ah pack — these represent meaningful specification boundaries, not just cosmetic facelifts. A battery from before 2017 is very unlikely to be a straight swap into a post-2017 car due to the different cell configuration and capacity, even though the physical housing may look similar. If your car sits near one of these boundaries, confirm the exact battery generation and specification with the breaker against your registration before purchasing.

No — trim level does not affect battery fitment on the BMW i3. Whether your car is a standard i3, the i3s (the sportier variant with wider tracks and retuned suspension), or a Rex (range extender) model, the high-voltage traction battery specification is determined by the production year and the capacity variant, not the trim. Do be aware that the i3s and Rex models have other differences the breaker will want to confirm, but trim alone is not a fitment factor for the battery.

The Rex (range extender) models carry a smaller high-voltage battery pack than the equivalent standard i3 of the same era, because space is shared with the petrol range-extender unit — so a Rex battery and a non-Rex battery are not interchangeable. Always tell the breaker clearly whether your car is a Rex or a standard i3 when requesting a quote, as this is a critical fitment detail beyond just the year.

The 2018 BMW i3 uses the 120Ah high-voltage battery pack introduced that year, which differs from the 94Ah pack fitted to 2017 models and the 33kWh pack in 2013–2016 cars — so year matching matters significantly here. Ideally source a battery from a 2018 or later i3 with the same 120Ah specification, and confirm the exact pack code with the breaker against your registration to make sure the battery management system and physical connectors are compatible.

2016 and 2017 represent a significant capacity boundary on the i3 — 2016 cars use the 33kWh (60Ah) pack, while 2017 saw the introduction of the larger 94Ah pack in a revised housing. Because these packs differ in cell count, physical configuration, and the way they communicate with the car's battery management system, crossing this boundary is not a straightforward swap. Name this boundary clearly when speaking to the breaker, and have them confirm compatibility against both donor and recipient registrations before committing.

Battery capacity is a core fitment specification on the BMW i3, not a cosmetic detail — the car's battery management system, thermal management, and software are calibrated to a specific pack. Fitting a higher-capacity pack from a newer car into an older i3 is not a plug-and-play upgrade and may require software changes or may simply not be supported; this is something to route directly to the breaker and, if needed, a specialist BMW EV technician rather than assume it will work.