Battery suddenly drops 30% during night

[abovetherim22]

Phone has been dropping ~30% instantly sometime during the night then levels out. Doesn't seem like there is an app that is a heavy drain, could this be a bad battery?

 

[Rukbat]

That looks like a dendrite in the battery. (See https://www.google.com/search?q=lithium+battery+dendrite&ie=utf-8&oe=utf-8 for more information on dendrites.) The battery has to be replaced.

 

[abovetherim22]

Thanks for the info. I suspected it might mean there was a malfunction with the battery.