iPhone 7 battery drains really fast. No longer charging.

Hi everyone,

Several months ago my I unboxed a new iPhone 7, then about 2 weeks later it started draining the battery so quickly you could almost count down in seconds along with the battery percentage as it dropped. While the phone was on (but draining) I could plug in a power source and it would slow down the battery usage but the battery percentage would still decrease with power connected. Once the battery was drained and the phone was off, connecting a power source did nothing. No charge icon.

I have done many iPhone repairs in the past so, instead of sending it back to Apple (which was a mistake) I replaced the battery and the screen hoping it would resolve the issue. However the same issue happened.

Apple have made it very clear that they will not touch the phone due to the replacement parts. I know, I know, I should have sent it back to them under warranty.

Has anyone else experienced this same (or similar) issue with an iPhone 7? Or does anyone have any idea's as to what could be causing this issue?

Cheers.