Chosen Solution
hi after 2 years with my original battery, I decided to get a new one, so I bought an ifixit battery for my iPhone 8 plus, I follow the steps carefully . i turn it on and its working perfectly. but it’s not charging and the percentage not shown even Im sure it’s enaple on the settings and when i press save mode battery it’s not going to oragne shape . I think the dock port its working cause when i connected it’s turn on the screen but nothing happened. also there’s no heat in the back i can tell it’s not charging :(
I think you will find that a tiny component has been nudged or knocked of the board while doing the battery replacement. There are two mosfets, two diodes and a filter. Also with this model sometimes the two small pins on the battery connector get pushed into the plastic. These components supply the battery data to the CPU. It is definitely one of the above causing your issue. If you had some magnification you could check the components but they will need microsoldering to replace. See image with the red components you need to check.
First, try disconnecting and reconnecting the battery connector. If this doesn’t fix the issue, there may be an issue with the logic board, or your battery is no good. If it is an ifixit-branded battery, and it is at fault, it should be covered under warranty.
