Solar Panel Voltage Chart: Understanding Voltage Changes - ShopSolar.com
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Solar Panel Voltage Chart

Short on Time? Here’s The Article Summary

The article discusses the importance of understanding solar panel voltage, especially when choosing panels for homes, RVs, or camping kits. It explains terms like open circuit voltage (VOC) and maximum power voltage (VPM), which indicate the voltage output of panels under different conditions.

The article also mentions the nominal voltage classification system and how advancements like maximum power point technology have changed the need for matching panel voltage to battery voltage. Additionally, it touches on the impact of temperature on panel voltage and why understanding these factors is crucial for selecting an appropriate solar setup. The article includes charts and examples to help readers grasp these concepts.

Introduction

A solar panel voltage chart tells you what the voltage of your panel will be under different circumstances. This can be helpful if you’re looking to make the move to solar and want to make sure you get the correct voltage rating for your needs. 

We’ll also explain how temperature can affect the voltage output of your solar panels, so you can make the right judgment call when it comes to choosing panels for your home, RV, or camping kit.

Understanding Solar Panels and Voltage

Solar panel voltage output chart

Understanding voltage can be daunting, especially when you’re faced with new terms that you don’t understand at face value.

We’re here to explain those terms and give you examples in an easy-to-understand table format. This will help you understand the relationship between voltage at different stages.

For example, the voltage when your panel isn’t in use is different from its voltage when it’s drawing a current. These values are referred to as the open circuit voltage and the maximum power voltage.

We’ll explain this in detail below, but if you’re still feeling unsure and need a little help on your solar journey, feel free to give us a call to discuss your needs.

We have some great solar panel kits for homes that might work for you. If not, we’ll help you find what does!

Solar panel voltage drop chart

Open Circuit Voltage

The voltage at the open circuit, commonly referred to as VOC, is the voltage that will show on a reading when the circuit isn’t connected to anything. That means nothing is pulling any power from the circuit at the time.

Your reading should match the advertised voltage on the sticker at the back of your panel, as well as on the specification sheet. 

The current passing through your circuit will be zero at this time, so no power is dissipated.

Maximum Power Voltage

The voltage at maximum power, commonly referred to as VPM, is the voltage reading you’ll get when your panel is connected to the maximum load and is performing at its peak. This amount will be determined under standard test conditions (STC).

Once this test is performed, the company that makes the panels will place the VPM on a sticker on the back of the module, as well as on the specification sheet. This is a requirement for panel producers. 

If you look at the voltage output in graphic format, you will notice a downward curve trend. When the panel is performing beyond its peak performance as stated on the specification sheet, the curve starts to drop. This means it isn’t performing as well because you are drawing too much power from it.

Just before the curve drops is where you’ll see the VPM of a panel. This is the panel’s peak voltage output level.

Solar panel voltage range chart

You should note that the maximum power voltage isn’t easy to measure, and it’s not directly related to the overall system’s performance. As long as you’re using your module within the correct parameters, you won’t be able to diminish or degrade its VPM. 

It’s just helpful to understand in terms of making sure you know what your solar panels are designed to power.

Nominal Voltage

The nominal voltage is a classification system that originated when batteries were one of the sole providers of power. That means this number isn’t listed on a sticker or the informational sheet as you would expect the VPM or open circuit voltage to be.

It’s still useful to understand what it is, though.

Most systems used to have 12V or 24V battery packs. If you have a 12V battery, you could only use a 12V module, and the same applied to a 24V battery. A 24V battery voltage chart is a good place to start for general electrical usage, but you should size up or down to get one the right size.

Solar panel system voltage chart

The type of battery also dictated how the wiring inside a solar panel was done. 

This system worked well until the maximum power point technology came into play. The development of this technology is complicated, but all you need to know is that it’s the reason you don’t need to worry bout matching a 12V solar panel with a 12V battery anymore.

You might think that you could go for a 6V battery voltage chart and simply double the values, but that’s not really going to work. 

You can play around with these values to get the best value for your money. This change also meant that solar panel manufacturers could start designing solar panels to be more aesthetically pleasing and smaller in size, which of course has been a much-loved shift.

The change has, however, caused some confusion among solar newbies. We’re going to include a chart below to help you understand the solar panel-voltage relationship.

Nominal Voltage

Open Circuit Voltage

VPM

Number of Cells in Series

12

21

17

36

18

30

24

48

18

33

26

54

20

36

29

60

24

42

35

72

Temperature and Voltage

Solar panel voltage curve chart

Did you know that temperature can affect the voltage of your solar panels? This change is called the temperature coefficient of the panel. It refers to the difference in voltage based on temperature.

The voltage of a solar panel will be slightly higher in cooler climates. The value can be presented as a percentage change or a value change. It’s sometimes also presented as a voltage value change per degree value change. 

In the past, it was quite difficult to find this information. As technology has developed, however, it has become easier to find the temperature coefficient of your solar panels. 

Have a look at our battery discharge chart to understand more about the effects of temperature on voltage.

Why Do I Need to Understand This?

Understanding the voltage and other attributes of your solar panel is essential. When you understand its output abilities, you understand how many things you can power with it.

For example, if you have a small solar panel linked to a small battery and inverter, you’re not going to be able to power your refrigerator. You’d be able to power some small mobile devices, a light or two, and perhaps your TV. 

It’s also helpful to understand these factors if you’re a solar newbie and you’re making the switch. You’ll be able to assess what your needs are to power your home or RV and be able to pick a setup that’s adequate for those needs.

It’s also useful o understand that a solar panel’s rated voltage isn’t necessarily what its real output will be. Knowing this gives you the power to make decisions in real-world circumstances, and not what the sticker on the back of the panel tells you. 

Solar panel voltage efficiency chart

For example, now you know that the weather can affect the output voltage of your solar panel. If you live in a very cold place, you know this increases the voltage a bit, and vice versa. You can therefore buy a panel that’ll be perfect for your conditions and environment. 

The Voltage Output of Batteries

In addition to the voltage of your solar panel, you might also be interested to learn about the voltage of your batteries. We’ve got some useful guides that might help. Take a look at our 48V battery voltage chart and the 52V battery voltage chart to find one that’s right for you.

We hope you found this helpful! If you’re still feeling stuck, get in touch and we’ll make sure you find what you’re looking for.

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Article by

Cody Oehm

Cody is the Head of Marketing at Shop Solar, and joined the company in spring of 2022. 

He has an entrepreneurial background and has been in the ecommerce industry since 2015. With 4 businesses under his belt and a drive to make a bigger impact, he decided to team up with Shop Solar on their mission to make solar simple and affordable. You can browse best seller's here.

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