Can I run a 10.8 volt radio on 12 volts?

[SOHC]

I have an old hand held radio that the battery is shot, someone has been using a remote power supply to run it as there are 2 wires coming out of it, the instructions say that the radio can be used on no more than 12 volts or it will vold the warranty.

I was thinking about using the cigarette liter in the car to power it but I have seen upto 14.5 volts coming out of there.

Would this burn the radio out?