Running a Macbook Pro 2017 constantly plugged in

Question

I have a 2017 Macbook Pro which is my work machine. I wish to use my external monitor as the primary display. From experience, I know that the monitor works only when the Mac is plugged in to the AC adapter/charger. Is it okay to leave my Macbook plugged in all the time? Will that weaken and degrade the battery faster?

I used to do something similar with my 2015 Macbook Pro and it was eventually ruined because the battery was swollen. However, I was wondering if there is some new hardware and tech in the newer Macbooks that prevents overcharging in such scenarios.

Answer 1

Your battery will not overcharge by leaving it constantly plugged in. This is not new technology - the 2015 MacBook Pro also does not overcharge.

No matter how you treat your battery, there's also a risk that the battery will have a defect and get swollen. That is true for all makers of laptops - not just Apple.

Having the laptop plugged in and turned on all the time will ever so slightly degrade the battery faster. I personally would not worry about that.

macOS Big Sur 10.15.15 and later includes a feature known as "Optimized Battery Charging". In this mode, the laptop will attempt to limit the battery at 80% charged when plugged in - in situations where it predicts that you will not need the full charge. This is slightly better for the battery.

Answer 2

If you wish to ONLY use the external display then it has to be plugged in. As soon as you close the lid without power connected it will go to sleep.

If you use your laptop screen as well as an external screen then you do not have to have the power connected. However, your battery will drain pretty fast with an external screen connected.