Original post by: Atronx ,
Possible battery terminal or battery cable damage. The cheap batteries on amazon are a crapshoot. If the cable or terminal are damaged / crossed it will do all kinds of strange things to the phone. Things like sitting on 1 percent charge, loosing charge, causing no boot or boot loops. Strange but bad batteries can cause all sorts of other issues. Buy a premium battery from a reputable USA based parts supplier and try that first. Lots of iphone dr type stores are carrying cheap batteries they purchase for $4 in bulk.