I came across this app few weeks ago. And I'm the kinda person that doesn't like my battery percentage inside the battery but outside. So I went searching for the perfect app to use. And came across Accu battery on play store, I liked the app so much I had to look for the pro version.

Features;
It tells u the exact mAh consumption on the battery.
Gives battery advice and versions apps consuming battery.
Gives exact input ur charger takes to charge ur battery full. (U can actually detect fake or original charger with this app)
It shows u the wear and tear of the battery when charged to various percentage.
Gives you charge speed and voltage.
It also calibrates ur battery when needed.

It's the best battery I've come across.

Accu Battery is the name.