Besides watch face, How can I view battery indicator

Press and hold the MENU button - state of battery charge is shown at the top of the first screen. Press BACK to return to watch face.

Easy, peasy.

HTH

Awesome!  Thank you!

is there also an opportunity to see the battery in a percentage and not in bars?

Restart the watch while holding the ABC button pressed.

When you hold the menu button down it shows the remaining days on this charge in den circular field and then, after maybe a second, it switches to percentage. 

I think that is in Solar version only.

Oh okay. I only have the solar so I don't know the differences. 

Is there any way to get an alert when the battery is getting low? (I don't see such feature in the Instinct owner's manual.) It seems to me that this sort of feature could also be a substitute for showing battery charge on the watch face.

I get alerts when the battery is ruining low, at least during an activity, but don't know if there are any options for this.