Golf Pad automatically turns down screen brightness while in Smart Lock mode. As a result, it only takes 10-20% more battery compared to playing a round without Golf Tags. Majority of golfers can complete a full 18-hole round with battery to spare. However actual usage depends on the model and the age of the phone, as well as power use by other apps. We recommend to fully charge the phone before the round. If you notice that the battery is running low during longer rounds, please disable background sync, use power saving mode or consider a portable charger like this one. A quick charge between the holes makes a huge difference.