What cable should I use for my wireless iPhone charger on an iMac 24"?

Allan Fischler wrote:

Just got the iMac 24" cuz I couldn't wait any longer for Apple to possibly come out with a new 27. Boo-hoo. :) Confused with the USB ports. USB 3 and USB 4 - seems USB C fits in both.

The port and charging capability are identical for both ports. The difference will be in the data transfer speeds and other features like the Thunderbolt connection.

I have a wireless iPhone charger that previously went into my old basic USB port on old iMac. What cable do I need for my wireless charger?

Any USB-C cable should work. However, the USB-C ports (3 or 4) on the Mac may not provide enough power to charge the iPhone through the wireless charger however. Wireless charges generally require a lot of power since most of it is lost as heat, and the power delivery for USB-C ports may not be strong enough to engage the induction charging on the iPhone.

The USB-C cable does power up the charger, but my iPhone does not charge. Works fine on old computer so it's not the Charger. Clarification on USB 3 please. A link to a USB-3 cable would be helpful. Thank you!

USB-C 3 and USB-C 4 use the exact same cables. No functional difference between them.

Make sure the iPhone is correctly placed on the wireless charger.

I found Phil's answer unsatisfying . . . so I dug around and found this:

• USB4 is the latest USB standard, offering faster data transfer speeds and better product naming compared to USB 3. 
• USB4 requires the use of a USB-C connector, while USB 3 is compatible with multiple connector types. 
• USB4 has a theoretical maximum transfer speed of 120Gbps, while USB 3's fastest variant reaches 20Gbps.

copied from:

https://www.makeuseof.com/usb4-vs-usb-3-differences-explained/

For the charging, any cable with USB C connector will charge your device.

But there is a difference Between Thunderbolt 3, Thunderbolt 4, and USB4

Thunderbolt 3 and Thunderbolt 4 share the standard USB-C connector, and both have a top speed of 40Gbps theoretically.

But thunderbolt 3 is only 23Gbps of data (the rest reserved for DisplayPort video).

Thunderbolt 4 can transfer data at speed up to 5000 Gb/s. Theoretically. (3500 Gb/s is the max that you can get IRL).

Thunderbolt 3 can transfer data at speed up to 2700 Gb/s.

Thunderbolt 4 supports two 4K displays or one 8K display.

Thunderbolt 3 supports one 4K monitor. (or 2 displays at 4K but this is hard to get in real life).

The ability to wake a computer with the shake of a mouse or the tap of a keyboard is now standard on Thunderbolt 4 docks. (Unlike thunderbolt 3).

USB4 does not require certification, and it allows for variations in deployment.

Therefore USB4 can be anything. Usually, it means USB C connector with data transfer speed from 10gbps to 32gbps. But again, USB 4 can be anything, including a true Thunderbolt 4

Stop using a wireless charger. They are inefficient.

You can more quickly charge your phone using a direct cable and it is more energy efficient.

USB-C is a "Swiss Army Knife" connector.

USB4 is a new version of the USB standard that requires the use of USB-C connectors. You can plug a USB-C to USB-A adapter into a USB4 port. It's just that a computer vendor can't put a USB-A port on their system, and call that USB-A port a USB4 port.

It sounds like your old computer had a USB-A port.

If your iPhone charges with (iPhone -> wireless charger -> USB-A cable to old 27" Mac), but not with (iPhone -> wireless charger -> USB-C cable to new 24" M1 iMac), my first suspect would be the USB-C cable or adapter. All USB-C cables are not created alike with respect to power capabilities and data speeds. Many charging cables of the type you find in drug stores, supermarkets, etc. do not support data transmission or support it only at USB 2.0 speeds. Maybe some are the other way around and don't support even USB-A (USB 3.0) type power.

The main thread dates from June 2023. Somebody revived the zombie thread with a post in January 2024. Then another person revived it with a post in June 2024.

I'm guessing that the OP figured out the answer to their question last year, and hasn't been waiting all of this time for an answer to the question of what cable to use to charge their phone.

Mabundis wrote:

I found Phil's answer unsatisfying . . . so I dug around and found this:

• USB4 is the latest USB standard, offering faster data transfer speeds and better product naming compared to USB 3. 

That's what I said. "...The difference will be in the data transfer speeds and other features like the Thunderbolt connection. "

• USB4 requires the use of a USB-C connector, while USB 3 is compatible with multiple connector types. 

Correct, but on an iMac the port is the same for both USB3 and USB4.

• USB4 has a theoretical maximum transfer speed of 120Gbps, while USB 3's fastest variant reaches 20Gbps.

copied from:

https://www.makeuseof.com/usb4-vs-usb-3-differences-explained/

Also said that, though not as specifically.

"The difference will be in the data transfer speeds and other features like the Thunderbolt connection."

The OP was not really asking for specific numbers. Only for clarification on the difference. For charging purposes, which was the original question asked, the data transfer speed is meaningless.

Geeez — Dude! what is with all the meta comments, from you and others?!

What you wrote just sounded to ME a bit ambiguous, even with parts contradictory.

None of these meta comments address the ISSUE . . . they are only about one's ego.

IF your reply was indeed clear and complete enough — I imagine the discussion would have been CLOSED . . . but it plainly was NOT!

It was meant as cursory explanation. Not specifically detailed since it was not really important to the charging question.

Which contradictions?

What issue?

The only question was whether they could use the ports to charge an iPhone and why it wasn't charging with the wireless charger. That's it. Data transfer speeds and other factors involving the ports were not addressed since they were not required in the original question.

All your clarifications are fine and absolutely correct, but they don't technically address the OP. The OP was asking about charging, using a wireless charger at that. In that respect It was answered almost a year ago.

Its nice that you wanted to add more details, but they were not necessary then for the original question.

The fact USB-4 is faster that USB-3 and has other supported features, has no bearing on "charging" a connected device. The power delivery is the same in both cases, specially on an iMac.

You should read the original post too - it wasn’t asking what USB4 is. Phil answered OP on the money.