I've been having issues with managing battery life today (first day with One UI 2.0) and I've pinpointed the main cause of this, Samsung Accessory Service. Disabling this caused me to disconnect from my Samsung Galaxy Watch so that's not recommended, so I would suggest optimizing it from the app info menu. I only just did this so I am not aware if battery life increases now to normal, but beforehand, I lost 25% of battery in 1 hour.
