Following the seemingly endless discussions about the “true” range of eclectic vehicle has been fascinating. Remember the New York Times’ article Stalled Out on Tesla’s Electric Highway and the ensuing public back and forth between Elon Musk and John Broder?
There are differing opinions on the range viability and long term durability of the battery packs in pure and extended range electric vehicles. Unfortunately, too many of these analyses begin with “I am not an engineer, but…” So it was refreshing to read the objective scientific analysis of the Tesla Roadster battery pack published recently by Plug In America. The highlights of this report are:
- The capacity of the battery pack after 5 years and 50,000 miles is expected to be 80-85% of the original, an average loss of about 3.7 miles (1.6%) per 10,000 miles driven. This is better performance than Tesla’s promised estimate of 70% of the original capacity. However, the study found considerable variation among vehicles with similar mileage.
- The study found no apparent deterioration in capacity over vehicle’s age, although the oldest data was 4.5 years old (The Roadster production ended in 2012).
- The studied did not detect an effect of hot climate on the battery’s cell life. Tesla’s thermal management system, which is designed primarily to ensure performance in cold weather, also helps protect the system from very high operating temperatures.
Plug In America also publsihed a similar analysis of the Nissan Leaf battery pack.