The
Anchor Alarm app on my Ipad runs in the background with the monitor off and uses approx 10% of battery life overnight. More expensive hardware, but substantially more useful than a hand held
gps. In fact, that is exactly why I bought my Ipad. I wanted a backup
gps. I did not want an Ipad at the time and now don't know how I would get along without it. Rented
movies, real time weather
radar (when close enough to shore), wind
charts, email, navigation
charts, pictures, etc, etc.