The positive pole of two solar panels is connected to the positive pole, the negative pole is connected to the negative pole in parallel, and a two to three amp diode is connected in series in the circuit. In theory, any twelve solar panels. The volt battery can be directly charged.
But that said, since the power generated is only ten watts, if you charge a battery with twelve volts and twenty amp hours, it will take twenty-five to thirty hours, and two to three hours during long days in summer. Winter days, short days, take about a week.