Apple’s 29W power brick cannot power 15W MagSafe Duo 9to5Mac

You might think that Apple’s 29W power brick would be more than capable of powering both an iPhone 12 and an Apple Watch with the MagSafe Duo charger. After all, the combination of devices can be charged with as little as 15W. But this is not the case; instead, you need the replacement 30W power pack …

AppleInsider found the information on a new support page. This begins by saying that a 20W or higher power brick is sufficient.

Use the included USB-C to Lightning cable to connect your MagSafe Duo charger to an Apple 20-watt (W) or higher recommended Apple USB-C power adapter * or a compatible third-party USB-C adapter. It can also be connected to a USB-C port on a Mac or PC.

But that asterisk leads to a footnote:

* The Apple 29W USB-C Power Adapter is not compatible with the MagSafe Duo charger.

The reason? MagSafe Duo requires a protocol known as USB Power Delivery 3.0 (often abbreviated as PD 3.0). The 29W charger predates this protocol. It was replaced in 2018 by a 30W version which is PD 3.0 compliant and therefore compatible with the new charger.

The MagSafe Duo charger is designed to negotiate the maximum power of up to 9 volts (V) and 3 amps (A) with a USB PD compatible power adapter. MagSafe will dynamically optimize the power delivered to the iPhone. The power delivered to the iPhone 12 at any time will vary depending on various factors, including temperature and system activity.

Of course, there is a wide range of third-party products that support PD 3.0.

Apple’s support page also says you need to turn on the charger prior to placing his phone on it.

It is important to plug it into a power source before placing your iPhone on the MagSafe Duo charger. This allows MagSafe to verify that it is safe to deliver maximum power. If you place your iPhone on the MagSafe Duo charger before plugging it into a power source, simply remove your iPhone from the MagSafe Duo charger, wait three seconds, and then place it back to resume full power delivery.

In addition, the company warns of possible cosmetic damage to both the case and the charger.

If you keep your iPhone in a leather case while charging with your MagSafe Duo charger, the case may show circular fingerprints from the compression of the leather. This is normal, but if you are concerned, we suggest using a non-leather cover.

As with most soft materials, the accessory cover can experience normal wear and tear over time. The hinge area of ​​your MagSafe Duo charger may wrinkle over time if it is kept in the folded position. Leaving your MagSafe Duo charger in a very hot environment (such as the interior of a car on a hot day) in the folded position may cause deeper and more visible wrinkles in that area. This does not affect the functional performance of the accessory.

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