The new 16-inch MacBook Pro charger has both good and bad news. The good news is that it’s the first on the market to support a new high-power charging standard that, for the first time, allows USB chargers to output more than 100W.
The bad news is that because the technology is so new, there isn’t yet a USB-C cable that works…
When the USB-C standards were being established, there existed a separate charging standard called USB-C Power Delivery (PD). This enabled for up to 100W of power to be provided via USB-C connections.
That was acceptable at the time, but when more powerful computers became available, more power was required. Apple was a leading force behind the development of a new standard that supports power supply of up to 240W. USB PD 3.1 Extended Power Range is the name of the new specification (EPR). This provides up to 48V at 5A and can handle loads of up to 240W.
16-inch MacBook Pro charger limitation
Apple’s new 16-inch MacBook Pro charger supports the new USB PD 3.1 EPR standard, making it the first charger on the market, as far as I can tell. Apple’s version is restricted to 28 volts.
Because the standard is so new, there isn’t yet an EPR-rated USB-C to USB-C cable available.
I expect that it is a USB PD 3.1 EPR charger (the world’s first), using the first new voltage level, 28V at 5A. Apple was instrumental at proposing the 28V, 36V, and 48V new voltages levels to USB’s working groups, so it would make sense that they were planning on releasing the first implementation.
There are yet to be a C-to-C cable rated at EPR levels though. Apple’s using some proprietary cable to MagSafe.
That implies you won’t be able to charge a 2021 16-inch MacBook Pro at full power using one of the USB-C ports for the time being. Apple’s new USB-C to MagSafe 3 cable, on the other hand, supports EPR. That means you can use the MagSafe cable to obtain full power – even the 30-minute 50% charge.
The restriction is just temporary. There are USB-C to USB-C EPR cables in the works, and you’ll be able to use them with the 16-inch MBP charger whenever they’re ready. However, for the time being, you’ll need to use the MagSafe charger to get the best results.