PLS, it's your project, we don't even have a schematic, do you? Few more details, from the mismatched parts, I can see several potential projects. What voltage is the lamp, from the rest of the parts it could be either 6v or 12v. You would be better off sticking to 12 volts throughout, but your solar panel is a little weak to charge a 12v battery. 8 volts from the regulator is a little high for a 6 volt battery. My guess. is that you want the light to come on, if you lose the mains power, but don't see why you need the solar panel.