can you fast charge an iPhone 13 Pro Max by connecting to a 24" iMac?

24" iMac has 143W Power Adapter and it uses between 43W (Idle) to 84W (Intensive use) --> iMac (24-inch, M1, 2021)

Each port may not give out more than 15W each depending upon the iMac usage. So it may not fast charge.

• Thunderbolt 3 (up to 40 Gbps)
• USB 4 (up to 40 Gbps)
• USB 3.1 Gen 2 (up to 10 Gbps)

iMac power consumption and thermal output - Apple Support (IN)

I think you can charge your iPhone 13 Pro Max throught 24" iMac.

You can read this article Fast charge your iPhone - Apple Support that may be helpful to you.

Thanks, Have A Good Day.

Tin Thanh

Use fast charge with certain iPhone models. You can recharge your iPhone up to 50 percent battery in around 30 minutes.

Fast charge your iPhone - Apple Support