I was having difficulty getting even 10 hours out of my Gear 2. I checked Gear 2 application manager on my Galaxy S5 phone (About Gear) tab, (Battery Usage) tab, and saw that "Contacts" were causing a battery drain in the 40% range. This was the cause of my problems.
The following corrected my battery drain issue and now I can get a couple days between charges;
1. Open Contacts on your phone and see if you have multiple linked apps per contact name. My galaxy 5S contacts show "connected via" then show an icon for each app such as Phone, Cloud, Messenger, Magicjack, Outlook ect.
2. I went to each app shown in step 1 as linked to the contact, in the android (settings), (Applications), (Application Manager) and changed the apps setting from sync contacts to do not sync contacts.
3. I then went back into my phones contacts and selected the link icon beside the "connected via" and removed all links other than "phone" and " Cloud".
4. After un-linking each app in the contacts list, I found that I had several contacts for the same person/name in my contacts list. I then opened each duplicate contact name and deleted each contact that was previously synced and linked by the app the I turned sync off for.
Now my when checking battery usage "Contacts" is listed as using 1% of battery instead of 40% range. My gear 2 battery lasts for a couple days now.
I hope this helps.
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