About two weeks ago, my lightning cable was torn a little but it was working so I thought I don't need to replace it immediately. A few days ago, after a night of charging, when I woke up in the morning I noticed that my charger and phone got very hot, and it didn't charge to %100, it just charged to %60 or something like that. I thought it happened because of lightning cable.
Next day, I used my mother's charger and cable, which are working properly, and it charged my phone without any problem. Yesterday, I bought a new lightning cable from Apple and attached it to my charger, I left the phone for charging for two hours, then I saw that charger and phone got hot, charged to %60, again. And I noticed that charger is making a noise like buzz.
Yesterday evening, I charged my phone to %100 with my mother's charger and cable then unplugged the device, didn't left the device charging all night. This morning, I noticed that battery decreased to %83 from %100, in stand by mode. And after an hour of using the phone (web browsing, snapchat, messaging etc.) it didn't even decreased %1. It is still %83. By the way, my charger still charges when plug it to phone but I think that it stops charging when it gets hot.
So, there are two questions I want to ask:
Did my charger get out of order and why? Did my phone's battery get harmed by my charger (getting hot, not charging properly, buzzing)? Thanks for your help.