How to Measure Energy From a Solar Panel to a DC Motor

Measure the output of a solar panel using a watt meter.

You can measure the amount of energy being generated by a solar panel running a DC motor with the aid of a watt meter. This value can be compared to the manufactured energy output of the cell to ensure the motor is getting the energy it needs. A watt meter measures the electrical power in watts generated by a device. A watt equals a joule-per-second and is the rate of generating or using energy.

Things You'll Need

• Watt meter

Instructions

1. Turn on the watt meter. Select the watt setting on the meter by pressing the button labeled "Watts."

2. Disconnect the solar panel from the motor. Plug the solar panel into the watt meter.

3. Record the reading on the watt meter once a day for 10 days. Make the measurements at the time the motor is usually running. Take the average of the ten watt readings by adding them all together and dividing by 10. For example, the average power might be 20.0 watts.

4. Determine the time in seconds the motor must run each day. For example, if the motor must run for 2.0 hours a day convert hour to minutes by multiplying by 3600 seconds per hour. Completing this step leads to a time of 7200.0 seconds.

5. Multiply the average power times the time to obtain the energy in joules supplied to the motor by the solar panel. Performing this step you have 20.0 joules per second times 7200.0 seconds, or an energy of 144,000 joules.

References

• Georgia State University: Power