Why does my iPhone 5S battery drain?

Hey guys,

I had a an iPhone 5s come in the other day. The lady had travelled had the battery replaced while she was travelbig in Nepal. They placed an incorrect battery in the iPhone and it fried the board.

I replaced the board, and battery, updated the software, shut off all battery drain settings, hard reset it, and the problem still exists!

I was told the issues could be in the lightning charger. She used cheap chargers. Is there a possibility the lightning charger has a short and is draining the battery?

What else should I look into?