Wesley's Tool-Box

Along with my Bolt EV passing the 160,000 km milestone, the new battery that came with the recall has logged more than two years and 57 thousand kilometers of use. So it was a good time to check on how its performance compares to the original battery. The video I uploaded at YouTube on this topic covers everything including how the data was obtained, but I'll cut to the chase here. The data for the old battery is divided into two ranges, the first part that spans 25 months and 51,585.4 km, and the second part that covers 23 months and 52,940.1 km. The new battery's data is treated whole, totalling 57,945.3 km and 28 months.

The division on the old makes it ideal to explain its degradation trend in just two linear polynomials, and also is close to a single quadratic or cubic counterpart for the scope in question. The results showed that the degradation of the old battery in its first two years was steep, amounting to about 0.660 kWh of loss every 10,000 km. In contrast, the new battery was doing much better at about 0.311 kWh per the same distance. While the degradation slowed down for the old one in the subsequent years, it was still worse than the new one's initial performance. So it's evident that the new battery is much more resilient.