(an electronic device) is out of juice

When an electronic device's battery is low, you can say that it has "run out of juice". "Juice" is a slang term for electrical power.

You can also say things like:

It's almost out of juice.

It doesn't have enough juice.

Other phrases for talking about a low battery are:

My phone is dying.

My battery is almost out.

This phrase appears in these lessons: