Solar panels use the photons produced by sunlight to generate direct current (DC) electricity. Solar panel amps current will flow from a panel connected to an electrical circuit. How many solar panel amps of electricity the panel will produce depends on the power of the solar panel, the amount of sunshine falling on the panel and the characteristics of the circuit to which the panel is connected. Calculate the amps produced by the panel making measurements using a digital multimeter.

how to calculate solar panel output

Calculate solar panel amps

Look at the back of the solar panel or consult the installation manual and find the maximum rated power of the panel in watts. Look for the maximum power voltage, Vmp, which is in volts.

Calculate the current when it is generating its maximum power. Calculate the current in amps by dividing power in watts by the voltage in volts.

For example, if the solar panel is rated at 175 watts and the maximum power voltage, Vmp, is given as 23.6 volts, then calculate the current as 175 watts divided by 23.6 volts, which is equal to 7.42 amps. This is current produced by the solar panel at full power.

Take a digital multimeter and switch the dial to direct-current volts. With the solar panel connected to an electrical circuit, measure the voltage between the positive and negative terminals of the solar panel. Make a note of this value. Disconnect the solar panel from the circuit and switch the digital multimeter to measuring resistance. Measure the resistance of the electrical circuit in ohms and write down this value. Reconnect the solar panel to the circuit.

how to check solar panel amps

Calculate the current in amps flowing through the circuit by dividing the voltage by the resistance. This relationship is Ohm’s law.

For example, if you measured the voltage as 22.1 volts and the resistance of the circuit as 3.2 ohms, divide 22.1 by 3.2 ohms to get 6.91 amps.

This is the actual current produced by the solar panel, given the amount of sunshine on the panel and the characteristics of the circuit.


Measuring the voltage of a single solar panel is not dangerous.

If you have several panels connected together, however, consult a qualified technician to assist you in this procedure.


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