USB-C Digital AV Multiport Adapter limits charger wattage to 55W

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USB-C Digital AV Multiport Adapter limits charger wattage to 55W

I'm having a weird problem with a USB-C Digital AV Multiport Adapter. If I connect a power charger through the USB-C port on the adapter, the charger power is limited to 55W (as reported by System Information), which leads to a bunch of other issues, such as battery discharging over time. If I connect the same charger to a dedicated port on the laptop, the charger wattage is back to the nominal one. This happens with two different MacBook Pros. A different adapter doesn't show the same issue.

I suspect a faulty adapter, but I'm wondering if there's anything I can try to salvage it. Compressed air didn't seem to help.

MacBook Pro 16″, macOS 10.15

Posted on Jul 8, 2020 6:15 AM

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Answer 1

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Grant Bennet-Alder

Level 10

133,183 points

Jul 8, 2020 7:22 AM in response to Sir W

Some more information about those adapters is available in this article:

About the Apple USB-C Digital AV Multiport Adapter - Apple Support

Your computer performs best when connected to AC power. It can use the full output of the Power Adapter AND when doing especially challenging work will also freely "borrow" power from the battery. In some cases, the charged state may even decline during stressful work.

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