Chosen Solution
Hi guys, I have an iPhone 5s here and I’m trying to figure out where the issue lies… it’s loosing around 30% battery life overnight! Overnight the phone will be left in low power & airplane mode. background app refresh has also been disabled *auto brightness is off It’s currently running iOS 11.2.6 *Has been restored to factory settings. No iCloud, no apps, pictures ect. Literally a fresh install of iOS multiple new batteries fitted (same result) im thinking it’s the u2 ic chip that’s failing but I’ve dealt with a few of these before and they will ither drain power much faster than this or shut off randomly (an issue I have not had with this iPhone) Really stuck! Any help would be greatly apreciated :) Thanks!
You guessed right, pretty much the U2 Tristar charging chip is the last thing to rule out. Though shorted cap(s) on the logic board can also cause this kind of issue which will require some time to measure capacitors for any short to ground with a multi-meter and the metal shields removed, which all require micro soldering to do.
