iPhone 4 replaced battery 100% charged, but shuts down unless plugged into wall charger
Hi everyone,
I've had my iPhone 4 (AT&T) for almost 2 years now so the battery life is rather terrible and I decided to replace the battery. I ordered a battery from PhonePartsUSA and followed the instructions on ifixit. I had some minor issues with the tiny contact piece, but once I wiped it down with ethanol, it was seemingly fine. When I plugged it in I saw the charging/lightening bolt icon in the upper right with an increasing percent. When it reached 100%, I unplugged it from my wall charger. The issue now is that after 1-2 minutes of use on battery (browsing internet on WiFi), my iPhone turns off by itself.
Also, when I plug it in to my laptop via USB, iTunes does recognize it.
I would like to self-repair, if possible, and was hoping someone here could point me in a direction (software, hardware, etc).
Thanks in advance!
iPhone 4, iOS 6.1.2