Creating a watch face as an App, Refreshing the UI?

What you do is set up a timer for say a minute, and then in the call back for it, you do the Ui.RequestUpdate() call, so each time the timer fires, the screen updates.

As far as battery, it really depends on what you device app is doing. The reason there's limits to what watch faces can do is to preserve battery, and you said you're doing a device app to do things a watchface can't do.

Brilliant! Thanks for that, Jim.

I do use an app as my every day watch face so that I can have it doing things like web requests and have open ant+ channels constantly listening for devices. I have a lot going on and have the onUpdate call every second and web requests every 30 seconds or so. The battery life is heavily dependent on the device as much as what you are doing.

FR935: ~1% / hour battery usage in general use. 4% when using GPS.
F5+: ~2.5 to 4% / hour general use. ~6 to 7% when using GPS

So the 935 works really well for this where you don't even need to plug it in every day. With the F5+ I need to be careful to plug it in at night or it'll likely be dead in the morning.

Thanks, ekutter. That's really useful info to have.

If you take a watch face and turn it into a device app with a timer, say every minute, you'll likely see a an impact in battery, as I believe when a device is in "watch mode", the firmware itself does some things to preserve battery (maybe a slower CPU clock of something). You'll sometimes see a reference to "LPM" (low power mode) as it relates to the firmware itself, which is different than "low power mode" as it relates to CIQ watchfaces

the major drawback with the watch app approach is that you have to actively start the watch app, this in contrast to the watch face which just happens to be there whenever you exit from everywhere...