The voltage of a solar panel is based on the number of solar cells in a panel.Each different solar technology has a characteristic voltage per cell based on the physical properties of the materials that the cell is composed of.
There are two voltages that are important for a solar module:
- The open circuit voltage (Voc) is the maximum voltage that the cell will produce and it occurs when there is no current supplied by the module.
- The power point voltage (Vpp) is the voltage at which the maximum power is available from the cell.
Solar panels always produce DC current and can be used directly with a system that works on DC. But the biggest challenge is that the wattage, voltage and current from a panel vary. It varies with the environmental temperature and also with the amount of light it gets.
In fact higher temperature decreases the power output. A colder day and a good sunlight will result in better output from a solar panel.