Tesla Battery Reliability Questioned After New Tests

Concerns have grown regarding the reliability of Chinese-made batteries used in certain Tesla Model 3 and Model Y vehicles, following new technical assessments questioning their longevity and repairability. The issue centers on NCM811 lithium-ion battery packs produced by LG Energy Solutions, which are installed in a portion of these popular Tesla models. The topic resurfaces shortly after another report described the Model Y as one of the least reliable vehicles in its segment, adding further pressure to the automaker.

The findings were presented by EV Clinic, a company specializing in electric vehicle repairs. The group conducted comparative tests between battery packs from two suppliers: LG Energy Solutions’ NCM811 and Panasonic’s NCA (nickel-cobalt-aluminum) units. According to the results, Panasonic batteries demonstrated considerably higher durability. While LG’s NCM811 packs are estimated to last up to 240,000 kilometers, Panasonic’s NCA packs reportedly reach up to 400,000 kilometers, offering nearly double the expected lifespan under similar conditions.

Beyond lifespan differences, the biggest concern highlighted is repair complexity. EV Clinic states that during repair attempts, the LG NCM811 batteries showed failure rates exceeding 90%, with the replacement of individual cells described as “practically impossible.” Technicians observed uniform degradation across multiple battery modules, meaning that when a single cell fails, the deterioration tends to affect the entire module block. This structural behavior significantly limits the feasibility of partial repairs.

Due to repeated repair losses and the high number of unsuccessful interventions, EV Clinic has begun charging an additional “repair viability assessment fee” for customers with affected LG battery units. The company explains that this measure is necessary to offset financial risks taken when attempting to restore degraded packs.

Tesla Model 3 (Image: Tesla)

Based on its findings, EV Clinic has issued recommendations for owners of Model 3 and Model Y vehicles equipped with LG NCM811 batteries. The first suggested option is to replace the LG pack with a Panasonic battery, which is regarded as more durable and easier to repair. As an alternative, vehicle owners are advised to contact Tesla directly to request a full battery replacement under service support.

So far, Tesla has not publicly commented on EV Clinic’s statements. The analysis was initially shared through a detailed post on X (formerly Twitter), where the repair company published its test results and raised awareness among Tesla drivers. As attention grows around electric vehicle battery longevity, the discussion highlights the importance of durability and repairability in long-term EV ownership.

Filed in Transportation. Read more about Electric Cars, Tesla and Tesla Model 3.