Mac wakes up for no reason during night (El Capitan)

Go to energy saver preferences and disable Power Nap for both Battery and Power Adapter. Also, consider disabling wake for network access if you have that enabled.

That's the main cause of periodic wake events. You could have some off USB connection glitch that's waking things, but start with power nap and then eliminate connected USB devices one by one.

Lastly, in Bluetooth preferences, you might choose to not let bluetooth devices wake your Mac in the Advanced settings (button in the bottom right of the preference pane).

There's nothing wrong with those wakes as I see it - how long is the machine awake each interval? 10-15 seconds or 10-15 minutes?

What worked for me (issue with battery drain after sleep):

Settings & Prefs -> Energy Saver -> Power Adapter , Uncheck Wake for Ethernet network access

Settings & Prefs -> Bluetooth , Turn off

Device: El Capitan - Mid 2010 15" I don't have power nap on this model

My logs were showing the following before:

<Notice>: Wake reason: EHC2
<Notice>: Wake reason: EC LID0
<Notice>: Wake reason: PWRB (User)
<Notice>: Wake reason: EC LID0
<Notice>: Wake reason: EC LID0
<Notice>: Wake reason: EHC2
<Notice>: Wake reason: EC LID0
<Notice>: Wake reason: EC LID0
<Notice>: Wake reason: PWRB EC LID0 (User)
<Notice>: Wake reason: EC LID0 EHC2