California will begin increasing the battery warranties mandatory on electric cars. Currently most cars embrace an EPA recommended 8 year / 100,000 mile battery warranty. But California will require a more stringent warranty next year.
This may change when you want to purchase one. While these warranties are only required in California, because of economies of scale, and competition, some auto makers next year may extend their EV battery guarantees to match in other states.
Keep in mind these policies, set by the California Air Resources Board (CARB, or ARB for short) apply based on Model Year, starting with the 2026 Model Year. So some cars sold next year will have the new guarantees, and others may not. It is unclear if any auto makers will extend this to 2025 Model Year cars sold in 2026, to prevent confusion.
2026 Model Year – 70% capacity guaranteed for 10 year / 150,000 miles, whole battery. Per pack must retain 70% for 8 year / 100,000 miles.
(This initial change will harmonize CARB BEV cars with plug-in hybrid / PHEV cars, which already have a 70% / 10 year / 150,000 mile warranty).
2030 Model Year – 80% capacity guaranteed for 10 year / 150,000 miles, whole battery.
2031 Model Year – Per-pack guarantee bumps to 75% for 8 year / 100,000 miles.
Technical Implications
You might ask about things like Structural Pack. Tesla, and soon other auto makers to follow, use “just one big battery” that becomes part of the car’s frame.
The good news is, Tesla thought ahead of these requirements, and divides the structural pack into group segments, that then can be tested separately. It remains unclear what remedy Tesla has if a structural pack unit falls below 70/75% capacity. Likely they would still have to tear apart most of the car. This may explain why Model Y charges so slowly right now… they are throttling charge, to ensure longevity.
(Tesla does offer a battery health status on their touchscreen, but it gives no information other than “healthy” or “service recommended” – and is not useful in measuring how close a battery is to these thresholds).
CARB has ordered auto makers to provide some consumer-friendly way to check battery capacity. Ideally this will be available via a setting screen on the car. Today, it’s a mess. BMW requires you to enter Service Mode, and decrypt odd strings of text. GM and Tesla require you to go to a dealer, and pay them to check. Tesla won’t even tell you the capacity numbers (GM will), only if the battery passes muster or not.
Hopefully by next year, they will not fight the spirit of these regulations, and offer the same battery capacity check tools that most smartphones are now embracing… another industry that was slow to reform in this regard.
Market Impact
As of today, there are no indications PHEV battery warranties will change. Despite recent shifts towards most cars becoming PHEV, at least for the next several years, the CARB warranty will remain 70% capacity for 10 years and 150,000 miles. But this is less essential, seeing as a reduction in EV range for a PHEV is less harmful to the consumer, as they can still drive on gasoline and recharge the PHEV battery at even 30-50% of the original capacity. Most PHEV batteries don’t fail until around 25% to 33% capacity remaining, depending on the manufacturer.
One important thing to note is that most PHEV makers still are only honoring CARB warranties in California. This was a major debacle for BMW i3 owners, when early batteries started to fail quite early in their lifespan. Those in California were protected, but only if they had the i3 REx (PHEV) variant. BMW would not match the warranty for BEV/EV-only versions of the i3, leaving those customers in a far worse state.
Hopefully with greater consumer awareness, there will be more pressure on EV makers to take these warranties nationwide. This is a reasonable threshold that just should be the warranty term on these cars. Otherwise, people will have a new reason to hate BEVs… premature battery replacement.