There are a few tips you can use to maximize your device battery efficiency:
Turning 'Off' WIFI, Bluetooth, Notifications and all other apps will decrease your battery consumption.
Use your phone in 'Sleep' mode (turn off the screen) in between shots/uses, you can keep battery usage below 50%.
Also, note that Hole19 works on the course without an internet connection (via the device's internal GPS), so you can turn your cellular connection 'Off', after downloading the course, to further conserve of battery.
We recommend that you close all App's running on Background so you can limit your device performance to the round of Golf.
For the iOS users with iOS versions ≥ 8.2: you can turn Airplane Mode 'On' while playing your round.