Solar Panel Output Voltage: How Many Volts Do PV Panel Produce?

For many calculations, we will need to know how many volts do solar panels produce. It’s not all that easy to find the solar panel output voltage; there is a bit of confusion because we have 3 different solar panel voltages. To help everybody out, we will explain how to deduce how many volts does a solar panel produce. Further on, you will also find a full solar panel voltage chart.

Namely, we have to come to terms with the fact that there are several different voltages we are using for solar panels (don’t worry, all of these make sense, we’ll explain it). These solar panel voltages include:

  • Nominal Voltage. This is your typical voltage we put on solar panels; ranging from 12V, 20V, 24V, and 32V solar panels.
  • Open Circuit Voltage (VOC). This is the maximum rated voltage under direct sunlight if the circuit is open (no current running through the wires). Example: A nominal 12V voltage solar panel has an open circuit voltage of 20.88V. This sounds a bit weird, but it’s really not.
    voltages in a solar system
    Voltage output directly from solar panels can be significantly higher than the voltage from the controller to the battery.
  • Maximum Power Voltage (Vmp). The is the voltage when the solar panel produces its maximum power output; we have the maximum power voltage and current here.

Here is the setup of a solar panel:

  • Every solar panel is comprised of PV cells, connected in series. Most common solar panels include 32 cells, 36 cells, 48 cells, 60 cells, 72 cells, or 96 cells.
  • Each PV cell produces anywhere between 0.5V and 0.6V, according to Wikipedia; this is known as Open-Circuit Voltage or VOC for short. To be more accurate, a typical open circuit voltage of a solar cell is 0.58 volts (at 77°F or 25°C).
  • All the PV cells in all solar panels have the same 0.58V voltage. Because we connect them in series, the total output voltage is the sum of the voltages of individual PV cells.
solar panel output voltage in series connection
Within the solar panel, the PV cells are wired in series.

If you know the number of PV cells in a solar panel, you can, by using 0.58V per PV cell voltage, calculate the total solar panel output voltage for a 36-cell panel, for example. You only need to sum up all the voltages of the individual photovoltaic cells (since they are wired in series, instead of wires in parallel). Here is this calculation:

36-Cell Solar Panel Output Voltage = 36 × 0.58V = 20.88V

What is especially confusing, however, is that this 36-cell solar panel will usually have a nominal voltage rating of 12V. Despite the output voltage being 18.56 volts, we still consider this a 12-volt solar panel. What gives? Which is the correct voltage; 12V or 20.88V?

This might sound weird, but both are correct and useful:

  • Nominal 12V voltage is designed based on battery classification. With solar panels, we can charge batteries, and batteries usually have 12V, 24V, or 48V input and output voltage. It is the job of the charge controller to produce a 12V DC current that charges the battery.
  • Open circuit 20.88V voltage is the voltage that comes directly from the 36-cell solar panel. When we are asking how many volts do solar panels produce, we usually have this voltage in mind.

For maximum power voltage (Vmp), you can read a good explanation of what it is on the PV Education website. In most cases, it’s not all that relevant when talking about solar panel output voltage.

Here is the nominal and open circuit voltage chart for 32-cell to 96-cell solar panels:

Solar Panel Voltage Chart (Cell Number, Nominal Voltage, VOC)

Number Of PV Cells In A Solar Panel: Nominal Voltage: Open Circuit Output Voltage (VOC):
32-Cell Solar Panel 10 Volts 18.56 Volts
36-Cell Solar Panel 12 Volts 20.88 Volts
48-Cell Solar Panel 18 Volts 27.84 Volts
60-Cell Solar Panel 21 Volts 34.80 Volts
72-Cell Solar Panel 24 Volts 41.76 Volts
96-Cell Solar Panel 32 Volts 55.68 Volts

As we can see, solar panels produce a significantly higher voltage (VOC) than the nominal voltage. The actually solar panel output voltage also changes with the sunlight the solar panels are exposed to.

Hopefully, this gives you a bit more understanding of solar panel output voltage (VOC), and how it relates to the nominal voltage we are all familiar with.

7 thoughts on “Solar Panel Output Voltage: How Many Volts Do PV Panel Produce?”

  1. Could you connect 3 300 watt 24volt panels in parallel directly to a 24V 900W Stainless Steel Heating Element (hot water tank) without any kind of controller and just get whatever heat is produced by the power that day? Is this too much of a load being 0.64 ohms at the heat element.

    Reply
    • Hi Garrett, I see what you mean, it does make a theoretical sense to just cut off the middle-man (inverter, charge controller, etc.) and connect 3x300W panels to 900W hot water tank. That would be great but, in practice, you can’t really do that. You do need a middle man (inverter, charge controller, battery).

      Reply
  2. If I have a 24v PV system, can I connect a 24v wind turbine in parallel with it and feed the combined outputs into a single inverter and then onwards into my house’s power system?

    Reply
  3. My panels have an Voc of 146.78V
    Vmp of 117.43V
    Operating current of 1.09A
    Short Circuit Current of 1.34A

    How can I determine what the output DC Voltage is so I can choose a correct micro inverter for this panel??

    Reply
    • Hi Jan, the highest voltage your panels will produce is Voc (146.78V). In most cases, you will have an output DC voltages of less than 120V; so a 120V micro inverter would be suitable here. 240V inverter would likely be overkill for these panels. Hope this helps.

      Reply

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