Power[watt]=Voltage[volt] * Current[Ampere]
if the panel is rated as 5v 200 mA then
Wiring multiple solar panels
This is required if your application need more power than rated. By connecting the positive terminal of solar panel of one panel to positive terminal of another panel and similarly connecting negative terminals of both the panel as shown in the figure below.
fig – 1 parallel wiring
The maximum current that can be delivered will be some of both current. The rated voltage will remain same.
This can be used if your application needs a higher voltage than the rated voltage. You can wire the positive terminal of one solar panel to the load and negative terminal to positive terminal of another panel as shown in the figure below.
Figure – 2 series wiring
In this wiring total voltage delivered will be some of the rated voltage of both panels. Current supply will remain same.