Incompatibility Issue With Apple’s USB-C Chargers
The cause of incompatibility problems with Apple‘s USB-C chargers has been determined. Accordingly, the reason why a 29 W charger cannot charge a device that draws only 15 W, is the dispute between these two devices over voltage and amperage. Apple‘s USB-C chargers charge some devices but not others. This situation can be confusing for users. For example; According to a report in 9to5Mac, the 29 W charger cannot charge the MagSafe Duo, although it has only 15 W.
Another example is seen in the charger that came with the iPhone 11 released last year. Apple‘s 18W charger that came with the iPhone 11 could not charge the HomePod mini at first. The company resolved this issue with a software update released last week. One of the reasons for this problem with Apple’s chargers is whether or not the protocol known as USB-C Power Deliverey (USB-C PD) is supported. For example, the 29 W charger did not support USB-C PD 2.0 or USB-C PD 3.0. In other words, although it could deliver the power that the device could draw, it could not respond to the charging request from the MagSafe Duo.
The Problem With Apple’s Chargers
The same was true for Apple‘s 18 W charger. The two devices in question were in disagreement over the voltage and amperage required. This issue was resolved with a software update that would make HomePod request the appropriate combination. John Gruber addressed this charging problem in an article he posted on his blog. Gruber stated that the iPad Magic Keyboard supports 9Vx3A = 27W input. However, he said that Apple’s 29W adapter could not provide this. The reason the 29W charger did not charge the iPad Magic Keyboard was that it had two configurations: 14.5Vx2A = 29 W and 5.2Vx2.4A = 12.48 W.
The 30W adapter had four different output options. The output of this 30W adapter, 9Vx3A = 27W, was able to charge as it matched the iPad Magic Keyboard input. In addition, this problem with Apple‘s USB-C chargers also occurs with third-party devices and “power banks”.