Hi!
I’ve been using a second monitor connected via USB-C, which trickle charges my MacBook Pro. I would prefer if it didn’t charge it at all, allowing me to properly cycle my battery. Is this actually possible?
MacBook Pro 14″, macOS 15.4
The CHARGER is inside the MacBook Pro, and is completely under program control. Your Mac accepts some power when needs to run, and accepts more power when intends to charge its internal battery. A power source like the Power Adapter can not 'force itself' on your MacBook Pro. Only the algorithms inside your Mac can decide when is a good time to charge the battery.
Any external power supply that provides "USB Power Delivery" (including certain Docks and Displays) must negotiate over the USB cable using USB Power Delivery Protocol, and can not 'force itself' on your Mac. The Voltage and Current are delivered ONLY after your Mac requests and the charger agrees to supply power under certain controlled conditions. The computer is in control of the entire process.
About battery health management in Mac notebooks - Apple Support
NOTE that charging to 80 percent is a side-effect, NOT the GOAL.
The goal is to have some hurly-burly around using your battery, either by your actually using it, or by leaving it less than 100 percent charged, so that the cells are not 100 percent charged 100 percent of the time. Battery Health Management will also from time-to-time let the battery decline slightly to 'get some exercise' and run lower (thought to be around twice monthly) if you do not do so by your ordinary use.
The CHARGER is inside the MacBook Pro, and is completely under program control. Your Mac accepts some power when needs to run, and accepts more power when intends to charge its internal battery. A power source like the Power Adapter can not 'force itself' on your MacBook Pro. Only the algorithms inside your Mac can decide when is a good time to charge the battery.
Any external power supply that provides "USB Power Delivery" (including certain Docks and Displays) must negotiate over the USB cable using USB Power Delivery Protocol, and can not 'force itself' on your Mac. The Voltage and Current are delivered ONLY after your Mac requests and the charger agrees to supply power under certain controlled conditions. The computer is in control of the entire process.
About battery health management in Mac notebooks - Apple Support
NOTE that charging to 80 percent is a side-effect, NOT the GOAL.
The goal is to have some hurly-burly around using your battery, either by your actually using it, or by leaving it less than 100 percent charged, so that the cells are not 100 percent charged 100 percent of the time. Battery Health Management will also from time-to-time let the battery decline slightly to 'get some exercise' and run lower (thought to be around twice monthly) if you do not do so by your ordinary use.
If the monitor has multiple inputs of different kinds, you could swap out a USB-C to USB-C connection for a USB-C to (DisplayPort, HDMI, etc.) adapter cable. Those just carry video signals; not charging power or data connections to downstream hub ports.
Atılay Sargın wrote:
Hi!
I’ve been using a second monitor connected via USB-C, which trickle charges my MacBook Pro. I would prefer if it didn’t charge it at all, allowing me to properly cycle my battery. Is this actually possible?
Stop trying to micro manage your batter/charging system. The Mac and the MacOS manage the power/charging system very well. Neither the computer nor the battery will be damaged by leaving it plugged in to a power source.
How to stop a USB-C monitor from charging my Macbook Pro
