I have an unrooted galaxy S6, Verizon, and Android 5.1.1 on it.Each night I fully charge my phone, and it never leaves my pocket after 6 am or gets used until 2 pm. At 2, the battery may be around 90% or it may be at 50% without any use. I discovered the battery was much lower if I had Wi-Fi on, even though I was never connected to Wi-Fi. Battery chart in settings says Google services or Google play services used all the battery.Please help, I've tried everything I can think of, and I'm usually good at this sort of thing.
Google Play services runs in the background to keep applications up to date and to sync your information to Google.
One possible cause of the battery drain could be if you have multiple accounts on your device. Your device will drain more battery to keep up with the demands on the services
Another possible cause of the battery drain could be a third-party application running in the background and using data from Google Play services
To fix either of these problems, you may want to boot your phone into Safe Mode. This will ensure that the Google Play services or anything else that could drain the battery aren't running. But at the same time, you can freely use Wi-Fi or any application that you choose to run.
To boot into Safe Mode:
Turn off your device and wait about 2 minutes
Once it is off, hold down the power button and the volume down button. You may release the power button when you see the screen turn on, but do not release the power button until the phone is completely turned on.
(Google Play services battery drain is from this source)