Can an M1 MacBook Pro use two powered hubs/monitors through USB-C ports?

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Can an M1 MacBook Pro use two powered hubs/monitors through USB-C ports?

I'm using an M1 MacBook Pro. Currently running the 5K LG Ultrafine monitor that Apple sells through its store. The monitor plugs into the wall and is powering the MacBook through one of the two USB-C ports.

I currently have a "dumb" unpowered hub for some peripherals. The hub is plugged into the other MacBook USB-C port.

I bought a CalDigit TS3 Plus hub to get more USB-A and USB-C ports, but it is powered through its own adapter. The CalDigit has two Thunderbolt 3 ports, one of which can supply 100W and is intended/labeled for connection back to the computer.

I'd like to connect this powered "for computer" Thunderbolt port to the laptop, so I can use the other CalDigit USB-C ports for peripherals.

The LG Monitor is already powering the MacBook. Is it ok to have two hubs/monitors potentially feeding power back to the MacBook through each of the two MacBook USB-C ports? Will the MacBook pick a port or draw power from each port? Is this configuration documented by Apple?

[Re-Titled by Moderator]

MacBook Pro 13″

Posted on Feb 9, 2025 7:10 PM

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Answer 1

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Tesserax

Level 10

159,166 points

Feb 10, 2025 10:42 AM in response to darrelstickler

Yes, you should be able to connect both the LG UltraFine 5K monitor and the CalDigit TS3 Plus dock to your M1 MacBook Pro, even though both can provide power. In theory, macOS will automatically regulate power draw, prioritizing one power source and preventing overcharging or electrical issues.

AFAIK Apple doesn't explicitly document multiple power inputs, but macOS natively supports multiple USB-C/Thunderbolt power sources and intelligently selects one. Apple's official documentation and tests with Apple's own Thunderbolt accessories (like dual Pro Display XDR setups) confirm that Macs safely handle multiple power sources.

macOS typically prioritizes the higher-wattage power source. Your MacBook is likely to prefer the 100W from the CalDigit dock and disregard the LG’s power, but this can vary depending on load.

You can use System Information to check which power source your Mac is using: System Information > Hardware > Power > AC Charger Information

What you are looking for are:

Wattage: Shows the current power source being used.
Charging: Indicates whether the Mac is currently drawing power.
Current (mA) and Voltage (mV): Shows power levels.
Power Source ID: Tells you which device is providing power.

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Answer 2

Feb 10, 2025 11:23 AM in response to Tesserax

Very thorough answer. Thanks.

For other's reference, to get to System Information, Apple menu > System Settings, then click General in the sidebar. Click About, then click System Report.

Note my system had this under AC Charger. Currently, I only have the LG monitor providing power. No Current or Voltage showing. The monitor doesn't have an ID so really no way to know what ID or Family means.

AC Charger Information:

Connected: Yes

ID: 0x0000

Wattage (W): 94

Family: 0xe000400a

Charging: Yes

The MacBook is running 15.3 (24D60). Perhaps this will change when I plug in the CalDigit. I didn't want to do it without some assurance I won't break something.

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Answer 3

Feb 11, 2025 5:45 PM in response to darrelstickler

@Tesserax

After attaching the CalDigit TS3 Plus to one of the MacBook ports (LG monitor attached to the other USB-C port), this is what the Power item looks like in System Report. CalDigit is plugged in as well. There is no specific information noting the two potential power sources.

[Edited by Moderator]

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Can an M1 MacBook Pro use two powered hubs/monitors through USB-C ports?

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