I'd like to better understand how charging cycles impact battery lifespan

jack3030 wrote:

Without questioning any of the advice offered, I'd like to better understand how charging cycles impact battery lifespan.

I've seen more than one very clear statement in these forums that the best way to extend the lifespan of a MacBook battery is to use it on AC whenever convenient. Great: that's clear, simple to execute and leaves the battery fully charged if you must disconnect from AC.

On the iOS side, though, Apple recently implemented an optimized charging option that, to me, seems in conflict with this approach. Simplistically stated, the objective of it seems to be to avoid holding the battery at 100% charge for an extended period. It observes usage patterns, charges to 80% 'immediately', then only goes to 100% when it expects it to be needed.

Determine battery cycle count for Mac notebooks - Apple Support

https://support.apple.com/en-us/HT201585

About Mac notebook batteries - Apple Support

https://support.apple.com/en-us/HT204054

Batteries - Maximizing Performance - Apple

https://www.apple.com/batteries/maximizing-performance/


Battery charge cycles don't necessarily have anything to do with battery condition or lifespan. A low charge cycle count doesn't mean the battery is good or even healthy. Leaving the computer plugged in all the time won't magically increase the lifespan of the battery just because it has low charge cycles from not being used (if anything it will likely decrease its usefulness somewhat).

Batteries are composed of chemicals and these chemicals react to each other and the other components contained within the battery whether you are using the battery or not. Batteries age like everything else whether they are being used or not. Just follow the guidelines provided by @leroydouglas and do not worry about the charge cycles.