Pix of the back show 12-24vDC or 15vAC.
If this is correct, you can use any 12v DC battery. Of course the power draw and the capacity of the battery will determine how long the device runs. (A device that draws 100mA will last 10 hours on battery with 1000mAH capacity > 1000/100 = 10)
I'd double check with the owner's manual about DC power.
Terry