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“What is my solar panel voltage?” It is a question that beginners often ask. All the different voltages can be confusing, and not knowing if your PV modules are 12V or 24V makes it impossible to use. Fortunately there are easy ways to find out.
At the back of a solar panel is the specification label, where it states whether the module is 12V, 24V or 48V. A 36 cell solar panel is usually 12V, while 72 cell modules are often 24V. A voltmeter can also determine the solar panel voltage.
How to Find Out Your Solar Panel Voltage
If you bought the solar panel, check the rear panel or look in the owner’s manual. There you will find the voltage and other solar panel specifications.
if you do not have the manual there are other ways to find out.
- Count the cells on the solar panel. A 36 cell panel is most likely 12 volts. A 72 cell solar panel is probably 24 volts.
- Divide the panel watts by its rated current (amps). Example, 100W / 5.5 amps equals 20 volts. It is a 12V panel because 12V systems generate 18-20 volts.
- Use a voltmeter. Any voltage above 12 volts and below 24 volts means it is a 12V system. Any measurement above 24 volts means the panel is 24V.
If you are going to buy a solar panel kit, the vendor will provide this information. Buy online for example, and the specifications are included with the product description.
If you are buying the solar panels in person, tell the vendor what type of solar panel voltage you want to buy. Provide as much information about your system as possible so they can tell you if the solar panel voltage is suitable for your needs.
Which Should You Choose 12V or 24V?
A higher voltage does not automatically mean it is better. A 12V 300W solar panel will outperform a 24V 150W solar panel, for example. Choose the voltage that best matches your power requirements.
If you need less than 1000 watts, 12V solar panels are suitable. It is also ideal for:
- A small home or cabin
- RVs, vans and other motorhomes
If you live off the grid or in an RV, a 12 volt solar panel system is ideal. Most RVs, campers and boats are designed for 12V battery banks so 12V solar panels are the ideal match.
Unlike modern homes, RVs use 12 volt systems to power refrigerators , microwaves, AC units, lights etc. Small DIY solar projects will run fine on 12V.
If your power requirement is between 1000 watts to 5000 watts, go with 24V or 48V solar panels. You can also opt for 48V for high power usage. 24V is ideal for:
- Medium to large houses
- Small offices
- Heavy power use
During the early days of solar power, 12V was often used in homes. As solar systems became more powerful, 24V became more common and today it is the standard. Even 48V systems are becoming more popular.
If you are not sure how much power you will need, go with 24V. Buying a higher voltage system allows you to use thinner wire gauges , and that can save you money.
The bottom line is a higher voltage system can produce more watts at the same current.
- 25ah x 12 = 300
- 25ah x 24 = 600
- 25ah x 48 = 1200
You may not always need this much power, but if you do, it makes sense to go with 24V or 48V. If you have any plans of expanding your solar power usage, consider getting a 24V system. But if you only use a small amount of solar energy, 12V will be sufficient.
How to Match Solar Panel, Inverter and Battery Voltage
Inverters and batteries have their own voltages. You have to use the right one to run your solar system, but fortunately matching up is easy.
12V solar panels are best used with 12V batteries and 12V inverters. 24V solar panels should be used with 24V batteries and 24V inverters.
When we say a solar panel is 12 volts, this refers to the nominal voltage. Because solar panels can produce up to 18 or 20 volts when exposed to sunlight. The same thing with 24V and 48V systems, as the output can be higher.
This is not an issue because 12V inverters and batteries can handle the higher voltage. Some inverters even support 12V and 24V systems, but not all of them.
If you bought a solar panel kit, the owner’s manual tells you exactly what type of inverter, battery bank and charge controller the panels are compatible with. Contact the manufacturer if you are not sure.
In the meantime here are some reminders:
- You cannot charge a 24V battery with a 12V solar panel. But you can use a 24V solar panel to charge a 12V battery. The solar panel voltage must always be higher than the battery.
- If you are going to charge a 12V battery with a 24V solar panel, use an MPPT charge controller so the extra current is not wasted.
- The solar panel voltage should match the inverter. If the inverter supports 12V and 24V, you can use either one.
- The lower the solar power voltage, the thicker the wire gauge required to reduce energy loss.
12V, 24V and 48V Solar Panel Kits
There are different types of 12V and 24V solar panel kits. Small systems may consist of 12V or 24V solar panels, medium scale systems are mostly 24V and large ones are 48V.
A typical 12V/24V small solar system can produce 3kw a day. These are ideal for cabins, weekend camping retreats and RVs (if the panels are 12V).
A medium sized system consists of 24V solar panels and can produce up to 10kw or more a day. These are suitable for small homes or medium size homes that want to split between electrical and solar power.
The largest solar panel kits are 48V systems that generate up to 1000kw a month. This is enough power to run virtually all appliances. With this kind of power you can go off the grid.
These are just approximations and meant to give give an idea of what 12V, 24V and 48V systems are designed for. Again, more power is not always better. It really depends on your setup and how much solar power you need.
Can You Mix 12V and 24V Solar Panels?
If you have four solar panels, two are 12V 100W and the other two 24V 50W, can you combine them? The short answer is no.
You should not mix solar panels with different voltages because the current will be restricted. If you mix 2 x 50W 24V and 2 x 100W 12V solar panels, the output will be limited to 50W.
While you cannot mix solar panels, it is possible to convert a 12V solar panel into 24V by connecting them in a series.
Connecting solar panels in a series adds up the voltage, while connecting in parallel increases the amperage.
For example: you have 4 x 12V 100W solar panels. Each solar panel is 8.3 amps (100 / 12 = 8.3)
- You can connect all four in a series and get a 48V 8.3A solar array.
- You may configure the panels in parallel and get a 12V 33.2A solar array.
- You might also use a series parallel configuration and get a 24V 16.6A solar array.
Solar Panel Strings
If you have 2 x 50W 24V and 2 x 100W 12V solar panels, create separate strings for both. That is, connect the panels with matching voltages.
Make a string with the 24V panels and another string for the 12V. Connect the panels in each string in a series or parallel.
Once joined, you can connect each string to a separate charge controller. Make sure though the controller can handle the solar panel size you configured. The two separate strings now have their own controllers, but you can connect both to a single battery bank.
Most solar panels for homes are configured in parallel so the system can generate more power for the required loads. In some cases a series parallel combo may be more appropriate. Contact your solar installer to find out what is best for your system.
The various solar panel voltages may seem confusing, but only in the beginning. Basically you just need to pair the voltages of each component. And once you know what your power requirements are, it is easy to choose between 12V and 24V solar panels.