If you have a Moto 360 and a strong sense of nostalgia for Nintendo 64, download the Secret Agent Watchface and walk around with the Goldeneye 007 pause screen on your wrist (seen here, modeled by by Phandroid). The left bar seems to always stay at 100 percent (congrats, you're healthy!) while the right bar will go down according to the watch's battery life. And if Apple doesn't tempt you tomorrow, the more James Bond-appropriate all-metal Moto 360 is coming this fall.
If you don't have a Moto 360, you can do what I did about six months back and make your own $7 version. Touchscreen doesn't work but battery life is phenomenal.
Update: "Rmukapps," the app's creator, reached out to let us know about a beta version of Secret Agent Watchface (if anyone's curious to try) that will turn the left bar into the tethered phone's battery indicator, among other features.
ICYMI: The Verge's Moto 360 Review