Why does my iPhone 4s keep turning off after a replaced battery?

Hi Wyatt,

Just ensure that your iPhone is connected to DC input or has enough battery.

Try normal power-up:

Press the power/standby button and hold it there for a few seconds

If you tried the above for about 5-10 seconds but nothing happened, then try to force iPhone power-up.

To force it to power-up:

Press the Home button, hold it there, followed by the power/standby button, and hold it there when apple logo appears.

Hope it was helpful.

I have the same exact problem! I had my screen replaced by a telephone repair place so Apple refused to help. So I got another repairer to replace the battery, but to have it happen once more again. My phone would shut off at even 94% battery. The only way I could start it up again would be to plug it back into the wall to jump start it. Then, once it went back to lock screen, it would shut down again.

Will try the above process when it happens again.

I have similar issues but it doesn't turn off it just screens off and on after the timeout. so it'll be off, then randomly the screen shows then if I leave it sit for 30 seconds or whatever the screen goes back off and it just does this repetitively. It doesn't power on and off, just screen turns on and off....any ideas anyone?