My iPhone 13, purchased in April 2022, is down to 55% battery health and frequently shuts off unless it is charging. I want to have the battery replaced, but I'm worried about losing data during the repair. I upgraded to a 50 GB cloud storage plan because my phone has about 37 GB of photos, but syncing is extremely slow—only around 6 GB uploaded after six hours—and the photos aren't visible on my other devices yet. Is it safe to leave the phone plugged in until the upload finishes, or would it be better to back everything up to my Mac?
3 Answers
A wired backup to your Mac may be faster and gives you another copy. Connect the iPhone with a cable, open Finder, select the phone, and choose Back Up Now. Enabling encrypted local backup is useful because it includes saved passwords, Health data, and other protected information. You can also import the photos directly into the Photos app on the Mac, then verify that they are actually there before the battery replacement.
Leave the iPhone plugged in while the backup or photo upload runs. With 37 GB of photos, the process can take quite a while, especially if your upload speed is limited. Since the battery is already degraded, keeping it connected during the backup is the safest option.
The phone’s storage capacity won’t make cloud syncing faster. The important thing is to make at least one complete backup—either let the cloud upload finish while plugged in or create a local backup on the Mac and confirm it completed before taking the phone in.

That makes sense—the slow progress is probably just the amount of data and the upload speed, not necessarily a problem with the phone.