I'm a newbie on solar, but this should get this started.
1) Go down to the auto parts store and get a digital voltmeter. With this (among other things) you can measure the output of your solar panel. The panel should have two output wires. One is positive and one is negative. Put it out in the sun and throw the voltmeter on it.
2) Become familiar with this: Watts=Amps*Volts. Solar panels deliver watts at a certain voltage. Divide the watts by the voltage to get the amps. Charge controllers are rated in maximum amps. Do you have a charge controller and what is it's max amps?
3) If you wire 2 panes together in parallel, I do not know if they need to be the same voltage and/or wattage? Maybe not, but if you wire them in series the voltage adds together.. wiring 2 12 volt
panels together in series will give 24 volts. If each of them is 100 watts then you will get 100 watts (at 24 volts).
- If you do not find a new panel that matches the one that you have I do not know whether you can hook them together or not.