Disappointing battery life

Hi. Moved from a hammerhead to the 1050 for better battery. However I am getting max 13 hours. 

I have Di2 / garmin heart rate monitor, garmin single sided pedal, Varia RCT and the light set to auto. This does not include using navigation. 

was hoping this set up would get me the nearer the 20 hrs, that are advertised. 

Any suggestions to help or improve the battery life?