Your Nokia phone has a reserve Battery!
Here's a sneak peak Do u know your Nokia phone has a reserve of 50% battery yes! Its true..!!Check ya out
Hidden Battery power
Imagine your cell battery is very low , you are expecting an important call
and you don't have a charger. Nokia instrument comes with a reserve
battery. To activate, press the keys *3370# Your cell will restart with
this reserve and the instrument will show a 50% increase in battery. This
reserve will get charged when you charge your cell next time.