MacBook Pro 2021, battery's health

Hello joshelyn1,

Thanks for that info and for choosing the Apple Support Communities. If we understand correctly, you have questions about the battery on your new MacBook Pro. The good news is you can use or leave your MacBook Pro on the charger with no issues and here are some Apple resources to help explain more on expected behavior:

About Mac notebook batteries

See how apps affect Mac performance, battery runtime, temperature, and fan activity

Batteries - Maximizing Performance - Apple

Batteries - Why Lithium-ion? - Apple

Cheers!

Thanks for replying, joshelyn1, and that additional info. Put it a different way, your Mac has built-in a system that when it reaches 100% battery while on the charger, will stop charging until it drops to 99% and then will accept power again until it is 100%. Please see these Apple resources for more about battery cycles and battery health on your MacBook Pro:

Determine battery cycle count for Mac notebooks

About battery health management in Mac notebooks

Have a great day and thanks for using the Apple Support Communities!

That computer is a battery-CAPABLE device. It is not optimized as a battery-operated device like an iPhone.

Your computer performs best when connected to AC power. It can use the full output of the Power Adapter AND when doing especially challenging work will also freely "borrow" power from the battery. In some cases, even with the power adapter connected, the charged state may even decline during stressful work.

When used only on battery, your computer has no extra cushion of power, and will perform more slowly. However, for ordinary non-stressful tasks this may not be objectionable (possibly not even noticeable.)

In general, you should ALWAYS connect AC power when it is possible to do so, and only run on batteries (which will be somewhat slower) when no AC sources are at hand. There are three micro-controllers cooperating on battery and charging issues, and your Mac will NEVER over-charge.

jdo_apple wrote:

Thanks for replying, joshelyn1, and that additional info. Put it a different way, your Mac has built-in a system that when it reaches 100% battery while on the charger, will stop charging until it drops to 99% and then will accept power again until it is 100%.

Right idea, but with Battery Health Management OFF, the number it is allowed to drop to can be closer to 92 percent.

With Battery Health Management active, it optimizes for longest battery lifetime, and can allow the battery to drop much lower -- based on your typical demand -- such as to 80 percent.

If you expect to use it on battery soon, you turn the feature off to top off the battery now in preparation for an AC off-power expedition.

Battery charging levels are maintained under computer control. There is no penalty for keeping it connected to the power adapter at all times. Periodic "exercise" is no longer required by Apple battery guidance articles.

But It is very difficult to keep your computer at 100 percent, because if you use it heavily, it will typically decline to 92 percent before initiating a Charge Cycle. That number will be lower with Battery Health Management active.

Optimizing battery charge levels is a job computers can do well. People are not very good at it. Leave it to the computers.