Why is my battery acting crazy?

[Bibimbab]

So I charge my phone up to 99%, unplug it and turn it off and go to sleep. When I wake up in the morning I turn it on and it's on 2-4%... this has been a regularity now. I also notice that when I unplug the charger and do some stuff ( open some apps and such) battery always stays at 99% while the phone is still on, it doesnt drop. I just got a new battery so I don't think it's a battery issue.

Forgot to mention it's Samsung Galaxy Core Prime if that helps

 

[Atifbaig786]

Coz bro your charger or powersupply is mad.
Try using a Good charger or clean power source.

 

[SexyLi]

Have you ever turned off your phone? Or just close the screen? You can close those temporarily unused software when you close your phone screen.

 

[Rukbat]

If a phone goes from 90% (or somewhere around there) to 2-4% by being turned off for 8 hours, I'd definitely suspect the battery, even if it's new. It could just be factory defective, it could be throwing a dendrite (see Lithium Battery Dendrite links) or something else. If Settings/Battery doesn't show any abnormalities, I'd try to return the battery and get a different brand. (That's no guarantee, we still don't know exactly what causes dendrites, but it gives you a chance.)

The other thing, if the phone is rooted, is to recalibrate the battery file - Battery Calibration (Root).