Why does Tesla recommend 80% charging for NCM batteries?

People use their batteries very differently. Some may only consume 10% in a day, others 50%, and some even require more than a full charge daily. So why does Tesla set 80% as the default charging limit for most users?

From a battery health perspective, 50% state of charge is actually the most stable. But if a manufacturer simply told users to "keep your battery around 50%," most people would find that confusing and difficult to apply in real life.

That’s why 80% has become the compromise. It offers a balance, enough range for daily driving while still helping to extend battery lifespan. If you want to maximize your battery’s health, it’s even better to adjust your charging limit based on your personal daily usage.

The graph below comes from a study aimed at developing NCM811 batteries specifically designed to support fast charging.

Wang, C.-Y. et al. Fast charging of energy-dense lithium-ion batteries. Nature 611, 485–490 (2022). https://doi.org/10.1038/s41586-022-05281-0

In the study, they compared battery lifespans when charging was limited to 75% vs. 70% state of charge and just that 5% difference led to more than double the cycle life.

The point of showing this graph isn’t to suggest all batteries behave the same. Rather, it's to illustrate how even a small reduction in charge limit can significantly affect battery lifespan. Of course, the aging curve will vary depending on battery design and chemistry. But the key takeaway is this: small changes in charging habits can make a big difference in long-term battery durability.