Chosen Solution
Hi there, My 5s started randomly switching off a few months ago (would do so even on 99% battery), but would usually turn on again in a few minutes, and the problem went away. But last week it started randomly switching off again, then started to switch off whenever it was disconnected from power. Now it won’t even turn on when plugged in. At first I thought it could be a battery issue, but the fact that it doesn’t work when plugged in makes me this the issue lies elsewhere. Any advice would be much appreciated. Cheers, I Edit: should add that the phone is in good condition, well looked after, and when working normally has good battery life.
We need history. Otherwise, I’d open up the iPhone, check that the battery is properly seated (should be unless it was previously and/or badly repaired). If reseating doesn’t change anything, I’d start by trying a new or known good battery. If you have to buy one, get it from a reputed seller like iFixit.com (I am not affiliated with them, I just buy my batteries from them because every where else I looked the quality was mostly terrible. Here they have mostly good batteries and the occasional bad one is covered by their warranty). Here’s the guide for replacing the battery. It also has links to the needed spare parts and tools. And yes having a dead battery is enough to keep the phone from booting even when connected to a power source. Other than the battery, you have board level issues. Many are repairable at an acceptable cost. But battery first.
