Chosen Solution
I bought a second hand iphone 6s, put a new battery in, i’ll plug it in to charge, it will boot up as normal, the battery charge % will go down so rapidly 1% every 30 seconds.. after 1-2 minutes the phone will just turn off and reboot itself. I have tested this new battery in a different 6s and it works fine and holds it’s charge. What could be my issue here? do i need to suck it up and take it to a phone kiosk for a real repair.
Your charging IC (the U2 chip) needs to be replaced. The “battery charge % will go down so rapidly 1% every 30 seconds” is the clue. The phone probably gets warmer than normal too. That’s a microsoldering job.
