Whats the volts of the panel? In max sunlight while a load is attached? Generally to charge a battery you want a slightly higher voltage than the battery but not too much higher. A 12 volt battery could be charged using a 14v or 15v source for example. But you need to disconnect the battery when its full. A charge controller between the panel and battery can prevent overcharging. Look at the charging cable for the battery and find the volts it supplies to the battery to charge it, and then make sure the panel supplies that. Disconnect at night if you dont have a charge controller or a diode in series with the panel to prevent drainage. But really at the electrical power you are messing with here its not a huge safety risk. Plug the shit in and see what happens :)