Help Understanding the battery remaining time.

[mm43]

I can't figure out the battery remaining time on my nexus 4.
When I charge it and view the battery later it gives me conflicting times.
99% = 1hr 40 mins
98% = 19hrs 27 mins
98% = 29 mins
This is on the battery app itself.
Checked battery in settings. This also says the same.
How do I know how long the battery will last if I go out? Am getting wary about using the phone.

 

[NeXuS4]

This acts weird on me too so I just use common sense while using it. I don't know what else to say.

 

[mm43]

This acts weird on me too so I just use common sense while using it. I don't know what else to say.

Hard to figure out if the battery will last if you are going to be out awhile though. Is this normal?