9v charger, if the output is usb interface, there should be marked output 5v voltage specifications, this is a fast charger, can automatically adjust the output voltage according to the charged device, so you can charge other mobile phones.
The mobile phone charger design input voltage is 220 volts, the current type is 50 Hertz AC. With 9 volts DC connected to the input end of the mobile phone charger, there are problems of low voltage and different current types, hasty access may damage the charger.
In fact, there are many ways to extend the battery life of the mobile phone, such as increasing the spare battery, can not replace the battery of the mobile phone can buy a charging bank. After all, the time and number of times away from alternating current can not be too much.