Gruber Motor Company, a Tesla service provider with a particular focus on the original Roadster, has released detailed information on how the battery packs in these cars begin to reach their end of life. According to the company, this information can teach us the symptoms to expect when multi-cell battery packs reach end of life in the many long-range EVs that came after the Roadster.
The video posted on Gruber’s YouTube channel explains that roadsters with batteries reaching end-of-life experience a significant drop in performance when their packs fail when they’re unable to exceed 60 mph, certainly at one Driving on the freeway or even driving up hills. Symptoms are subtle at first, in what one affected owner describes as “spongy pedal feel,” but then rapidly escalate, eventually rendering the car undriveable.
However, these results come from an unexpected source. Gruber has found that while roadsters are still intact with their original 200-mile range battery packs, cars equipped with the improved 400-mile range package that Tesla has been offering since 2016 are the ones starting out to fail.
The very first Tesla Roadsters were sold back in 2008 and are now 15 years old. Gruber quotes the automaker’s original chief technology officer, JB Straubel, as the expected lifetime of these original first generation multi-cell battery packs was 10 years. However, Straubel himself, who owns one of the earliest roadsters, publicly commented last year that he is surprised to report that his car is still running well, and he has revised his estimate the service life of the original packaging up to 15 years. Gruber’s own data supports this, with the company reporting that most roadsters it services with the original 200-mile range battery pack are still healthy, with no signs of slowing down.
2016, Tesla started the offer roadster Owners of a larger, improved battery pack. The upgraded packs cost a staggering $32,000 but are said to double the roadster’s range to 400 miles and increase its lifespan. These packs have been fitted with upgraded 3.2Ah 18650 cells compared to the 2.2Ah cells used in the original packs. Despite the promise of longer lifespans, these updated packs are now failing.
Gruber began investigating the upgraded packs when it received two separate Roadsters for service, both with upgraded battery packs, which exhibited identical symptoms his technicians had never seen before. After a lengthy and technical investigation, Gruber concluded that a “cell quality issue” was the primary cause of the packs’ failure. Without definitive confirmation from Tesla, they believe the upgrade packs sold between 2016 and 2019 were made in the same production run and so can deteriorate whether used frequently or sitting in a garage. Gruber states that these packs also never achieved their promised full range of 400 miles, eventually adjusting to a maximum range of 200 miles.
The data gathered from Gruber’s research has implications beyond Roadster with the improved battery pack. The Tesla Model S The following roadster uses the same 18650 cells. This data can also teach any EV owner how to tell when their battery pack is reaching the end of its lifespan.
Gruber shared his findings with Tesla. It even shipped an affected roadster to one of the automaker’s service centers for further testing to confirm its findings. The company reports that Tesla’s roadster engineering team is now working closely with them to find a solution.
