solar panel voltages

Can I keep the rated voltage of a solar panel of the same character and have a higher voltage?
I have a solar panel is 12 volts and produces 1.5 watts, and I'm planning to get a solar panel with 6-14 volts and 1-1.8 watts. How do I wire so everything stays at 12 volts, but gets a better rating hours for the power amplifier up? The listing on eBay that I am planning Get It On is manifold, ranging 6-14 volts, 1-1.8 watts.
when it says it needs 6-14 volts know what explains the variation. probably the level of sunlight. so it is very possible that the panel of 12 volts will react the same way, but is saying 12 Volts average exposure. I would recommend setting both in the sun next to each other and measure each strain under the same conditions. will likely be the same. then just connect them in parallel and have about 12 volts with double the power available.