iPad Air almost immediately shuts down when unplugged
I have recently replaced the battery of my iPad Air. At first it worked perfectly fine, and so I first fully charged it on the same day. Then I started using it when it was at 100%, back then the battery would drain completely normal, but later at around 40%, it suddenly turned off. Since then my iPad gets stuck in a boot loop everytime I am trying to power it on while it is not connected to a charger.
Now what’s really odd is that, when the iPad is connected to a charger, and I try to boot it, the Apple logo appears and it boots up just as it is supposed to, and everything works perfectly fine. It also charges up to 100% as usual. As soon as it gets unplugged it shuts off almost immediately, only in some cases it stays on for a few minutes, for example if I just let it stay at the home screen, then it doesn’t turn off at all. When I turn it back on , after it has shut down, it still has around 100%.
When I connect the iPad Air to my MacBook, coconutBattery says that the design capacity of the battery sits at around 96%.
I have just manually replaced the battery one week ago, with a new one I bought online.
I have already tried resetting it but that didn’t help.
I also tried charging it up for an entire day.
Could this be a battery issue, or could it be something besides that?
Thank you for help.