When should I replace the battery?

Hello Katsuma Toyama,

Welcome to Microsoft Community.

I understand that you cherish your Surface Pro 11 very much and plan to replace it when the battery is not in good condition, but in fact, there is no absolute rule, all the main judge whether the battery can support your normal use, once you find that even in the energy-saving mode, the battery will be consumed at a very fast speed, then this usually means that the battery needs to be replaced.

I can give some reference data based on experience.

When the battery leaves the factory, the capacity is usually 100%, and the capacity of the battery will gradually decrease over time. If the battery capacity is less than 80% of the original capacity, then it's time to consider replacing the battery.

Under regular use, the battery capacity usually decreases to 80% after about two years of use

The number of charge cycles of the battery is an important parameter. But let me emphasize that a charge cycle is one that uses all the power, but not necessarily one charge. For example, you might use 50% of your power for a day and then charge it completely. If you use 50% more the next day, this counts as a charging cycle. Most battery designs should still retain 80% of their original capacity after 300-500 full charge cycles.

In addition, there is a very intuitive physical situation, that is, if the battery expands, then please stop using your Surface immediately, please contact the Surface technical support team as soon as possible to replace the battery to avoid potential danger.

Usage time is not strictly one of the reference parameters, because the battery is actually worn down with continuous use, and if you use your Surface device at a high load when using battery power, the power consumption will be very sharp.

Best Regards,

Mitchell | Microsoft Community Support Specialist