December 28th 2017
By Mike Flaminio
My mom's iPhone 6 was going crazy. The battery charge was erratic starting at 100%, then quickly drop and suddenly shut down somewhere around 70%. It wouldn't power back up with a low-battery indicator, then wouldn't turn back on until it was 100% charged. When used while plugged in, it had all kinds of wonky performance.
Using Cocoanut app on the Mac, the battery read under 5% life. That would do it, I suppose. It had nearly 600 cycles. Apple states that its batteries are designed to last 500 cycles before degradation, but at that point, it should be about 80%. Cycles aren't the only factor that goes into a batteries, life, but this seems extreme.
Today, Apple announced an upcoming repair program, but I addressed my issue before this announcement. I got a replacement battery and did the repair myself. The iPhone 6 isn't too challenging for surgery. Before the battery swap, the app CPU DasherX measured the CPU clock frequency at 600 MHz. After the battery was replaced, it read 1,400 MHz. Changing the battery more than doubled the phone's performance. After fully charging, it seems the device is back to normal.