i am having same problem with my iphone 8 plus. My battery stay at 70% all day and not charging wirelessly or with charging cable after all day my phone trun off at 70%. After that I connect my iphone 8 plus on charging cable + wireless charger then it takes 2 hours for turn on. And now my phone trun off automatically with 100% battery or 60% 70%. Anyone have solution of this problem?? If anyone have solution then please contact me on my mail id inder.bhangu646464@gmail.com