Why does my battery drain on my Nexus 5 running Marshmallow?

[Taha Lodhi]

I'm running Marsh on my Nexus 5. The battery life is terrible. It shows that I could go from 98% to a complete discharge in just 3 hours. Is there a fix?

You can see where I charged it a bit in the last picture but it didn't help the overall battery life.

 

[B. Diddy]

Your screen is on the whole time, so it's projecting the battery life based on your current usage. If you kept your screen on the whole time, it would last for around 3 hours, since that's the usual maximum screen-on time a full battery charge can deliver on a Nexus 5. The Doze feature in Marshmallow improves standby time, but not awake/screen-on time.