In standard operation, the mobile screen does not go to sleep.
Depending on the model of mobile, the screen consumes more or less current so the battery empties more or less quickly.
If you have already recorded the speed changes of your route, you can put the screen to sleep which will reduce the consumption of the mobile and you will still have the audio announcements.

We do not always articulate words the same way when they are at the beginning or in the middle of a sentence. Speech recognition works best with words that are not at the beginning of a sentence.
If you experience a problem with voice speed recognition, say for example "Speed 30" or "Speed 30 Km/h" or "It is 30 degrees", it should help.

Your phone has Android 10 or higher. Localization runs in the background only if you authorized.
For that, to do this go to the Phone Settings and click on 'Applications -> Vit80 -> Permissions -> Location' and then click on 'Allow all the time'.
You can close the settings, you just allowed the localization to run in the background.

If you have any other problem, please, contact us here.