Computer batteries have a limited lifespan and degrade over time, so they’re often the first thing to go in a Mac laptop. You can replace a battery yourself or pay Apple to do it, but you should check its health. first. Any battery life issues you’re having could be due to a runaway process or just heavy use.
Check the Battery Cycle Count on Your Mac
A charge cycle is one full charge and discharge of the battery. Every modern Mac battery is rated for 1000 cycles; some older models (pre-2010) are rated for 500 or 300 cycles. While the battery won’t suddenly fail when it reaches its limit, it will start to hold less and less charge as it approaches that limit. Eventually, you’ll need to keep your Mac connected to its power cable to use it
To check how many charge cycles your battery has been through, hold down the Option key, click the Apple icon at the top left corner of the screen, and then select the About This Mac
And then click the button System Report as follow
It would be appear like this the System Report as follow
And choose Power on the sidebar as as follow
In the right pane, you’ll see all the stats for your battery. The “Cycle Count” entry is under the “Health Information” section.
The MacBook in our example has a cycle count of 291. The battery need to be replace, but it probably will need to be done later this year. If there is a problem with your battery, the “Condition” entry (which shows Service Battery in our example). For further information about your own Macbook Battery Lifespan check on Apple Support Website