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.

Since June 2018, I've been trying to drive my Bolt EV at every opportunity to personally confirm that an electric vehicle can rack up a lot of distance without much issues. One milestone I targeted is 100,000 miles (160,934.4 km) or just 160,000 km, since this is where all the car warranties expire. While I'm sure to reach that point this year, a more round number in terms of metric measurement - 150,000 km (93,206 miles) - has come to pass recently.

I know that there are already several instances of other electric vehicles surpassing two hundred thousand or more kilometers without major problems, so I had no worries about mine holding up. Still, I saw this as a good time to check up on the condition of the car before the government mandated biennial vehicle check-up is done in the May-July time frame.

On the battery front, things had been going really well. The current one is a 64 kWh version that was replaced for free due to the recall back in July 2022. So it's been in use for nearly two years. On one hand, it was disappointing to lose an opportunity to use the original battery up to its warranty limit of 160,000 km. On the other hand, this gave me a chance to compare the characteristics between the old and new battery packs.

And as it turns out, the new version seems to hold the capacity better than the old one. It started out at 60.61 kWh and the reported capacity hovered around between 59 and 62 kWh throughout all these months. With the car cruising past the 150,000 km mark, the capacity was at 61.19 kWh, which indicates almost no significant degradation. The old pack had a steady degradation of about 2 to 3 kWh at a similar time span and distance traveled, so that's a notable improvement in terms of capacity retention. A more detailed analysis of this might be prepared for either the 6-year anniversary or the 160,000 km mark.