How to Measure the Amount of Energy Collected by Solar Panels

Find out how much energy a solar panel can produce.

Most of the solar panels that you purchase from the store are labeled with the amount of energy they can produce. This label lists the panel's peak power output, which means the maximum Watt power they are capable of generating when exposed to full sunlight. If you want to confirm the figures claimed by the solar panel manufacturer or if the label is missing, you can measure the output figure yourself with the help of a small experiment.

Things You'll Need

• 4 power resistors of different values

Instructions

1. Get four power resistors of varying values (for instance, 100, 50, 25, 3 Ohms).

2. Calculate the voltage across the different resistors. Put the figures into a table. You need to measure the current (measured as voltage/resistor value), as well as the power output (measured as voltage x calculated current). For instance, if you draw a table, you will make four columns--resistance, voltage, current, and power. Let us say you use a 100 Ohms resistor, and you get voltage of 28.8 and 0.29 current. The power generated is 8.30 Watts. Similarly, if you use a resistor of 25 Ohm, the voltage and current produced will be 22.5 and 0.90 respectively. The power produced in this case is 20.25 Watts.

3. Plot a graph of the measured voltage and the calculated current, keeping voltage on the Y-axis (from high to low) and current on the X-axis (going left to right). Spot the center of the bend of the curve. This mid-point is the operating point of the panel, which means that the solar panel collects its peak power and generates maximum output at this point.

4. Multiply values of the current and voltage at the operating point. This will calculate each panel's peak power.

References

• Reuk: Measuring the Power of a Solar Panel