How to Determine the Yield From a Solar Power System

Typical Solar Panel Array.

Solar panels are rated in watts of electrical power (W = V x I), where V is the voltage of the panel and I is the current in amperes that can be drawn from the panel to obtain optimal output power (W). The industrial standard is to rate panels in full sunlight, at an operating temperature of 25 degrees Centigrade.

Things You'll Need

• Solar panel (12V, 2W)
• Volt meter (0 to 15 V)
• 6 resistors (12 ohm, 1W)

Instructions

1. Connect six 12-ohm resistors in series to make a total value of 72 ohms.

2. Connect this assembly across the solar call terminals.

3. Display the panel in direct sunlight.

4. Measure the terminal voltage of the cell, using the voltmeter.

5. Calculate the power in the resistor assembly, using the formula W = V x V/r .

Tips & Warnings

• The power output of the solar panel is rated at a panel temperature of 25 degrees centigrade. As the panel temperature rises the power output will fall.

• The resistor assembly will become hot. Be careful.