How Many Solar Cells Do I Need?
It is very important to choose the correct number of solar cells for your solar panel.
If you do not, then it will be difficult or even impossible to achieve the desired power output from your system.
Different factors go into determining how many solar panels you need.
In this article, we will answer the question of how many cells in a solar panel and also give information about the solar photovoltaic cell.
So Without Further ado, let’s go into details.
How Many Solar Cells Do I Need In A Solar Panel?
I’m going to answer this question in detail but first, let me explain what a solar cell is.
A solar cell or photovoltaic (PV) cell is an electrical device that takes light from the sun and converts it into energy.
How many solar cells are in a panel? There are typically 36 or 60 solar cells in one panel.
For example, the Kyocera KD140GX-LPB 140 watt monocrystalline photovoltaic module uses sixty to create an output of 16 volts and 14 amps.
The Kyocera KD210GX-LPH 210 watt polycrystalline photovoltaic module uses 36 to create an output of 21 volts and 18 amps.
but it is mainly dependent on several factors.
Related Article: What is the Difference Between Solar Cell and Photodiode?
What Are The Factors That Go Into Determining How Many Solar Panels You Need For Your System?
There are a few factors that go into determining how many solar panels you need for your system.
The first factor is the space available to install them, and whether or not they will be fixed in place.
A grid-tied home with one panel per every 100 sq ft of roof would require about 25 panels if it were in a temperate climate.
If you are planning on installing them yourself, it is important to remember that each panel weighs about 40-50 pounds and must be hung with the correct pitch for proper drainage.
Another factor is how many batteries you want your system to run at one time and what size of the inverter (if any) you are planning on using.
A larger inverter will require more panels to provide the same amount of power as a smaller one would with fewer panels.
There is also shade that can affect how many solar cells are in a panel you choose for your system.
Shade falling on just four inches of a 36 cell panel reduces output by about 50% and reduces power to much as 80% if you have a 60 cell panel.
The more cells in the panel mean that its efficiency is also increased; typically between 15-20%.
A smaller cell will produce less power than a larger one even if it has the same surface area exposed to the sun.
Additionally, If a cell is one inch by two inches it will typically produce more power than a cell that is four inches long and two inches wide.
Related Article: What Affects The Output Of A Solar Panel?
How To Calculate The Number Of Solar Cells Do You Need In Your Solar Panel?
Now that we know what a solar cell is and the different factors that go into determining how many solar panels you need.
Let’s look at an example of calculating how many cells are in your panel.
Let’s say I wanted to install a small grid-tied system on my home with no battery backup for power outages or other issues related to grid-tied systems.
I have an average-sized home of 1500 sq ft with a good amount of south-facing roof space to install the panels on, and I want to know how many cells in solar panels it will take for my system.
I would first determine the total wattage needed by multiplying each square foot of available space by the wattage I want to achieve per square foot.
For example, if we wanted a system that would produce 20 kWh of energy each day and my roof can fit 28 panels (1440 watts in total) it would be 1440 watts x 20 = 29,200-watt-hours or 23.44 kWh (round up slightly).
I would then divide the total wattage by 365 (days in a year) to determine how many kWh’s my system will produce each day.
In this case, it would be 29200/365= 77.84 kWh per day or 2344 watts of power produced daily for 24 hours.
Now that you know the number of watts you need daily, divide that number by the wattage of your panel.
Let’s say I was using a 210-watt Kyocera KD210GX-LPH solar panel for this example.
To do so would be 2344/215 = 11 panels (rounded down) to achieve my desired power output each day.
Related Article: How Much Voltage Can A Solar Panel Produce?
What’s The Difference Between 60-Cell And 72-Cell Panels?
60-cell and 72-cell panels are the same things.
They both have a bay of 12 cells that measure about 5” x 2.5” – this is the physical size.
The only difference between the two types is their voltage output.
In other words, one type will provide you with a different amount of watts than the other type.
A 60-cell panel will produce 18 volts at between 5 and 6 amps (watts) depending on exactly which kind of cell you have.
It can never be more than 18 volts, but it could go as low as 17 volts depending on the conditions.
It will never go more than 6 amps, though. We call this a “12 Volt System” because it outputs either 12 volts or 17 volts.
A 72-cell panel does not have a name for the system voltage because its voltage varies so much depending on how much of a load is being placed on it.
If you have a 12-volt load on it, it will read 17 volts or more throughout the entire day – even in the winter.
In the summer it could range from 38 volts right down to 0! We call this a “Voltage Source” because voltage can come from as low as 0 up to as high as 38 volts!
The higher voltage of a 72-cell panel provides more power output, but it is useless unless you have the correct wiring system.
A 12-volt battery simply cannot handle taking in 38 volts from a solar panel.
It will explode or at least be damaged beyond repair if it tries to take that much power into the battery.
So, if you have a 72-cell panel you’ll need to have either a 24 or 48-volt system. This also means that you can use smaller wires and reduce losses since the voltage is lower.
The only time it would be beneficial to purchase a 60-cell panel instead of a 72-cell one is if your solar panels’ maximum power point is at 17 volts.
In this case, a 60-cell panel will use that voltage and provide close to 6 amps of power instead of 4 or 5 amps from a 72-cell panel.
This could be beneficial if you have equipment that can handle the extra voltage, but it would be better to simply get a larger panel that does not have this problem.
Today, all major solar panel manufacturers produce both 60-cell and 72-cell panels except Caltech.
They are still producing 48-cell mono panels but may get out of the industry soon due to their new ownership by BYD.
So, if you are looking at a major brand like Kyocera or Suntech, you will always have a choice.
If you are looking at smaller brands, it is important to know if they produce 60-cell or 72-cell panels as their maximum PowerPoint.
If they do not state this information on their website, the only way to know would be to contact them and ask directly.
You could email or call them, but it is best to be in touch with them for other reasons anyway.
Related Article: Difference Between A Grade And b Grade Solar Panels
Pros And Cons Of 60-cell & 72-Cell Solar Modules
60-cell solar cells pros:
- produce a little more power per square foot.
- more efficient than 72-cell solar cells.
- more affordable.
- can be used in 12 volt or 24/48 volt systems.
- The cooler operating temperature of the 60 cell panel reduces the amount of power lost to heat so your batteries will last longer between charges and you’ll need fewer panels for a given load than with 72 cells.
- They can be used with MPP trackers – these are the best option if you want to maximize your output.
60-cell solar cells cons:
- physically large, so you won’t get as many watts out of a given area.
- The price is slightly higher than the cost of 72 cells for the same wattage output.
- They are not as efficient in low-light conditions, so you’ll need more square footage of panels to produce the same amount of power.
72-cell solar cells pros:
- The 72 cell panel is smaller and lighter, so it’s easier to mount. It weighs about 11 pounds less than the 60 cell version.
- It uses slightly higher voltages, which reduces losses in wiring long distances from one end of your roofline to another – this means that you’ll need fewer panels to produce the same amount of power.
- Higher voltages mean that you can use MPP trackers – these are the best option if you want to maximize your output and they work with both 60 and 72 cell panels.
72-cell solar cells cons:
- They cost more than a similarly sized 60 cell panel.
- The higher voltage means that you’ll need to use heavier wiring which increases costs – however, it’s still much lighter than copper cables even if you have an electrician install the system.
- They will produce less power under certain conditions, such as cloudy days or in the winter months when there is a lot of rain and snow.
In the end, if you have a 12 volt or 24/48 volt system that can handle it and need more power from your solar panels, get 60-cell panels.
Otherwise, go with 72 cells to save some money.
We hope you found this information useful.
Do you have any questions?
If so, please share your thoughts with us in the comments section below.