
- A Chinese company is selling upgraded battery modules for the aging BMW i3.
- The company claims its energy-dense pack can double its original driving range.
The BMW i3 is a great little electric car, albeit short on range by modern standards. It went on sale way back in 2013, when it was available with a rather small 18.2-kilowatt-hour battery pack.
That model, labeled as the “60” because of the 60 amp-hours capacity, had an EPA-rated range of just 81 miles. It was later upgraded with a 94 Ah battery that bumped the estimated range to 114 miles. It ultimately received a 120 Ah battery that gave the quirky EV an EPA range of 153 miles.
That’s a significant upgrade, but owners of the original i3 have been left with a rather subpar power source. That, coupled with the inescapable fact that batteries degrade over time, means the older i3s with the 60 Ah pack may now struggle to crack 70 miles on a full charge. That’s fine around town, but taking even a small drive elsewhere is an adventure to say the least.
But there’s a solution. A Chinese company called Martigi Manufacturing (MTG) claims to have developed a battery pack for the BMW i3 that can double the driving range of the 60 Ah version. That said, it’s compatible with all i3 versions, and it’s even an upgrade over the biggest pack available from the factory.
MTG’s solution is to offer higher-density Nickel Cobalt Manganese (NCM) cells made by China’s CATL that fit in the same battery cradle as the original Samsung-made cells. The pack configuration and the rated voltage are the same, but the energy capacity is higher.
There’s a total of 96 cells arranged in eight modules that can hold a total of 154 Ah or 54 kWh. That’s a 156% increase in capacity compared to the smallest 60 Ah pack. It’s also 28% larger than the largest original pack that was fitted to the i3.
MTG (the only approved seller for the battery) gets help from Echi Tech in the form of a reflashed battery management system, new electrical connectors and all the necessary hardware to change the cells at home. However, the reseller recommends that a competent service provider perform the upgrade.
The CATL pack can allegedly deliver a driving range of 248 miles on a full charge. That said, in a video published by MTG, an i3 fitted with its upgraded pack went 186 miles straight on the highway, maintaining 62 miles per hour. When it comes to charging, the new pack will behave the same as the old one, meaning it can accept up to 50 kW from a DC fast charger.

On Alibaba, the 154 Ah pack is priced at $5,800 without shipping. There’s also a $4,800 120 Ah version that can be a direct replacement for the original 120 Ah pack. MTG says the new modules come with a three-year warranty and are rated for 2,000 charge and discharge cycles. Whether or not that warranty can be honored in the United States is another topic.
That said, an original, BMW-sourced pack costs around $15,000 without labor. Even if the shipping costs for the Chinese pack are the same as the pack itself, the final check should still be lower than the original.