Navigation apps that use GPS generally use anywhere from 10-20% of your phone's battery per hour. This lines up with our RunHunters testing where we've dropped into suggested low power mode on iPhones if you've been using the app for more than 4 hours. Here are some tips on how to prolong your battery life.

1. Turn down your screen's brightness.

2. Turn on Aeroplane mode if you don't need to be contacted by anyone. This stops the phone continually trying to use other factors beyond GPS to pinpoint location. The GPS function will still work.

3. Force close the RunHunters app when you're not using it out on the trail e.g. you have a long section you're confident you know where you're going. For RunHunters iOS versions 4.1 and upward the app will 'remember' the run guide screen you were on when closing and take you back to that screen when you need to re-open the app.

4. Close any other applications running on your phone as these may be using power.

5. Keep in mind using services like streaming music, send messages, taking photos and video will all use battery power too.

6. User low power mode (iOs) or Battery Saver (Android).

Low Power Mode iOS reduces or affects these features: Email fetch, "Hey Siri" , Background app refresh, Automatic downloads, Some visual effects, Auto-Lock (defaults to 30 seconds), iCloud Photos (temporarily paused)

Extreme heat and cold can also reduce battery life signifcantly.

Recommendation. If you know you're heading out for a big day and are carrying a small pack with additional snacks and gear it's worth taking a small portable charge-pack for peace of mind. Definitely recommend popping it in a zip-loc bag to reduce risk of getting wet.