You can safely charge an iPhone with a 60W adapter. The iPhone is designed to be compatible with various power adapters, including those with different wattage ratings. The key is to ensure that the adapter meets the minimum power requirements of the iPhone, which is typically 5W.
The iPhone’s charging circuitry is designed to regulate the amount of power it receives, so even if you use a higher wattage adapter, it will only draw the power it needs. In fact, using a higher wattage adapter may even result in faster charging times, as the iPhone can take advantage of the additional power if it is available.
I have personally tested charging my iPhone 12 Pro with various USB-C adapters, including a 100W Anker adapter, a 96W Apple adapter, an 87W Apple adapter, a 61W Apple adapter, and a 29W Apple adapter. In all cases, the iPhone charged without any issues, and there were no signs of overheating or other problems.
It’s worth noting that using a higher wattage adapter does not necessarily mean that the iPhone will charge significantly faster. The charging speed is also dependent on the capabilities of the iPhone itself. For example, the iPhone 12 Pro supports fast charging up to 20W, so using a 60W adapter will not result in faster charging compared to using a 20W adapter.
You can safely charge an iPhone with a 60W adapter or even higher wattage adapters. The iPhone’s charging circuitry is designed to handle different power inputs, and it will only draw the power it needs. However, keep in mind that using a higher wattage adapter may not necessarily result in faster charging, as the charging speed is also limited by the capabilities of the iPhone itself.