Many individual silicon solar cells tend to have an open-circuit voltage of approximately 0.5 volts and a short-circuit output current limited to approximately 3 amps, therefore it is necessary to combine these individual solar cells together in either series and parallel combinations to obtain higher voltages and currents. But how many solar cells do I need to construct a PV panel.
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A commercially available photovoltaic panel is constructed using between 32 and 48 individual solar cells in series to give a panel capable of charging a 12V DC battery. But how many solar cells are in a solar panel, and how many solar cells do I need?. Well, as usual, it depends on your specific application.
The electrical power generated by a photovoltaic cell, ( PV ) has two components: Voltage ( V ) and Current ( I ). The output power generated by the PV cell is measured in Watts, ( P ) that the cell produces is the product of the cell’s output current times its output voltage. In other words, Power (P) = Volts (V) x Amps (I).
The voltage output of the photovoltaic cell remains fairly constant over a wide range of input light intensities because of the cells photovoltaic effect, just as long as there is some light. The output current, however, varies in direct proportion to the amount of sunlight entering the PV cell. The more light entering the cell, the more current it produces up to its maximum. The solar cell’s output voltage remains fairly stable from low to bright sunlight.
For the purposes of this tutorial here, we will consider a standard 4″ by 4″ (100mm X 100mm) poly-crystalline silicon photovoltaic cell. Mono-crystalline or amorphous silicon cells are available.
The absolute value of the voltage information will differ slightly, but their general performance tends to remain the same for all types of silicon PV cells for the amount of sunshine it receives on a sunny day. So how does a solar cell work.
A poly-crystalline silicon solar cell has an open circuit voltage of about 0.57 Volts at 25°C. Open circuit voltage means that the cell is not connected to any electrical load and is therefore not generating any current.
When connected to a load, for example a battery, the output voltage of the individual cell will drop to about 0.46 Volts at 25°C as the generated current flows. It will remain around this 0.46 V level regardless of the sun’s intensity or the amount of current the cell produces.
This decrease in output voltage is caused by internal resistance losses within the cell’s structure as well as voltage drops across the metallic conductors deposited on the cell’s surface to collect the current. Ambient temperature also has an affect on the PV’s cell’s voltage. The higher the temperature is, the lower the cell’s output voltage becomes as it heats up, which is strange seeing that they spend all day sat in the sun.
While the voltage produced by a silicon photovoltaic cell is fairly constant, its output current on the other hand varies considerably. The amount of usable output current that a cell generates depends on how intense the sunlight is shinning onto the cell’s surface, and also the voltage difference between the cell and the load.
Under normal operating conditions a poly-crystalline cell is rated at about 2.87 Amperes of current. This value can increase considerably on a very cold, very clear, very bright and very snowy winter’s afternoon. Also altitude is another factor that affects the PV cell’s output current. The higher you are, the less atmospheric conditions there is above and the more sunlight the cell will receive, assuming no clouds or snow. So expect to see current gains if used well above sea level.
When individual photovoltaic cells are assembled together into modules or panels they are generally wired in series. That is the positive connection or pole of one PV cell is connected to the negative connection or pole of the next cell, and so on until all the cells in the panel are connected together in what is called a series string.
When individual photovoltaic cells are assembled together into modules or panels they are generally wired in series. That is the positive connection or pole of one PV cell is connected to the negative connection or pole of the next cell, and so on until all the cells in the panel are connected together in what is called a series string.
This series wiring is done to raise the voltage of the panel. We said earlier that a single cell has a voltage potential of about 0.46 Volts. This is not enough voltage to do any usable work in a 12 Volt system. But if we add the voltages together of say 36 cells by series wiring them, then we have a working voltage 16.7 Volts, and that’s more than enough to charge a 12 Volt battery.
The operational voltage of a typical 12 Volt lead acid battery ranges from between 10.5 volts to 14 volts. The battery’s exact voltage depends on its state of charge, ambient temperature, and whether the battery is being charged or discharged at the time. It is this battery voltage curve that the PV panels are designed to fit and so MUST provide a greater voltage than the battery possesses. If the PV panel cannot do this, then it cannot transfer electrons to the battery and therefore it cannot recharge the battery.
The output current generated by a solar panel of 36 cells in total remains the same as the current produced by one single cell, about 3 Amperes. The series wiring technique causes the voltages to be added together, but the current remains the same. We could parallel connect all the 36 cells but this would add their currents together rather than their voltages. The result of this would be a solar panel that produces 108 Amperes of electric current, (36 x 3) but at only 0.46 Volts, too low.
Most photovoltaic (PV) panel manufacturers make 12 Volt solar panels for battery charging applications with 32, 36, or 48 cells in the series string. They are all rated at about the same current, being composed of the same basic cell. The difference between these panels is one of voltage. The question for us to answer here is how their output voltages relate to the voltages we require for our 12V charging system.
This size of photovoltaic panel has the lowest voltage rating of only 14.7 Volts (0.46 Volts times 32 cells). This is because it has the fewest number of PV cells in its series string. This panel design closely matches the charging curve of a standard 12 Volt lead acid battery. As the battery charges-up, its terminal voltage rises.
When this battery is almost full its voltage is about the same as the PV cell’s at around 14.7 volts. The 32 cell module simply hasn’t enough voltage to continue charging the battery when its full so cannot overcharge the average, small, lead acid battery.
The applications suitable for these small 32 cell solar panels are in RV’s, boats, garden lighting and summer cabins. These applications are characterized by their intermittent use and relatively small battery charging capacity. In these these types of low power applications, a 32 cell panel can be used with or without a charge current regulator as the batteries will not become overcharged if left connect to the panel during long periods of non-use.
This size of photovoltaic panel has an output voltage of about 16.7 Volts (0.46 times 36 cells). This is enough output voltage to be able to continue to charge a lead acid battery even though it may be already fully recharged. The 36 cell panel is suitable for a home based 12 Volt alternative energy system with high battery capacities as it has the higher output voltage necessary to recharge deep cycle lead acid batteries.
However, a 36 cell solar panel will require some form of charge regulation to prevent overcharging the battery during periods of high solar intensities or when battery usage is at its lowest.
A 36 cell solar panel tends to be more cost effective in a typical home power application because it can produce a good amount of current or high voltages at elevated temperatures. The higher voltage produced by the 36 series wired cells will more effectively recharges a large deep cycle lead acid batteries.
High ambient temperatures will cause the voltage of any PV panel to reduce slightly, but the 36 cell panel has more than enough voltage surplus to still be an effective battery charger even at high ambient temperatures.
A 48 cell panel is the big daddy of the PV industry. 48 individual photovoltaic cells connected in series produces an output voltage of about 22 volts. These large PV panels have sufficient output current capacity to charge a 12 Volt system, regardless of the battery’s voltage or high temperature.
However, these large panels do require some form of charge regulation in just about every application. They have the sufficient voltage necessary to raise a solar system’s voltage, while charging full batteries, to well over 16 volts. This over voltage is high enough to ruin any electronic equipment rated at 12 VDC so some form of protection is needed.
Generally, a 48 cell solar module has very specific applications where high power and currents are required such as in pumping water or are combined together with other 48 cell panels to produce a photovoltaic array. Solar arrays can combine many panels together in various combinations for increased power output.
Another disadvantage of this PV panel is its physical size and additional cost compared to 32 and 36 PV cell panels. 48 cell panels are larger so take up more roof space. On the plus side, a 48 cell panel will perform better in very hot areas and areas with very low levels of sunlight throughout the year.
Solar energy is key to the world’s transition to renewable energy sources. Solar panels, which capture sunlight and convert it into electricity, lie at the center of this technology. People may identify solar panels by their shiny rectangular shapes, but fewer know about the critical internal structure that enables functionality — specifically, how many solar cells there are in each panel.
Knowing the count of cells in a solar panel, how they fit together, and why various panels show different counts of cells is key for anyone thinking about solar energy, whether for home, business, or factory use. This piece takes a deep dive into solar panel cells, their setups, and how they affect performance.
What Are Solar Cells?
Solar cells are known as photovoltaic (PV) cells which form the basic components of solar panels. These cells are small; each is a semiconductor device responsible for the conversion of sunlight into electricity using the photovoltaic effect. Sunlight striking these cells serves to excite electrons thereby creating an electric current.
One solar cell generates very small power — usually about 0.5 volts. To generate adequate voltage and current for practical applications, these cells are joined in series and parallel arrangements to form a solar panel.
Standard Numbers of Solar Cells in Panels
Most solar panels have a standard number of cells, which directly influences their size, voltage output, and power capacity. Here are the most common configurations:
Configuration
Number of Cells
Typical Use
Voltage Output (Vmp)
Panel Size
32-Cell
32
Small off-grid applications
~16V
Very compact
36-Cell
36
RVs, boats, small off-grid setups
~18V
Compact
60-Cell
60
Residential rooftops
~30-32V
Standard size
72-Cell
72
Commercial and utility-scale
~36-38V
Larger than residential
96-Cell
96
High-efficiency premium panels
~50V
Variable, denser layout
Relationship Between Solar Panel Wattage and Number of Cells
The number of solar cells in a panel is closely linked to its total wattage output. Here's a helpful table showing typical wattage ranges and their corresponding cell counts:
Wattage Range
Typical Number of Cells
Common Applications
50W - 120W
32 - 36 cells
Portable systems, RVs, boats, small off-grid setups
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150W - 200W
36 cells
Off-grid cabins, backup systems
250W - 350W
60 cells
Residential rooftops
370W - 450W
72 cells
Commercial rooftops, utility-scale projects
480W - 600W
144 half-cut cells
Large-scale solar farms, high-efficiency systems
600W - 700W
156 - 168 half-cut cells
Ultra-large commercial and industrial systems
700W+
180+ half-cut or bifacial cells
Future high-power modules, bifacial applications
Note:
Half-cut cell panels (e.g., 144, 156 cells) are becoming the new norm in high-efficiency and large-format panels.
Higher wattage doesn't just mean more cells — it also involves better materials, larger cell sizes (such as M10, G12), and advanced panel designs.
36-Cell Solar Panels
36-cell panels are the traditional standard for smaller-scale solar projects, especially in off-grid environments like boats, RVs, or cabins. They provide around 18 volts at peak power, which is ideal for charging 12V battery systems (with the help of a charge controller).
These panels are relatively small and light, making them easy to transport and install. However, their lower power output (typically between 100 and 150 watts per panel) makes them less suitable for large residential or commercial installations.
60-Cell Solar Panels
60-cell panels are the most common choice for residential solar installations today.
A 60-cell panel is usually arranged in a 6x10 grid (6 cells across, 10 cells down). These panels typically produce between 300 to 400 watts of power, depending on the efficiency of the solar cells used.
Advantages:
Widely available and affordable
Good balance between size, weight, and power output
Easier installation on residential roofs
Because of their standardization, 60-cell panels fit well within the dimensions and weight limits preferred for homes.
72-Cell Solar Panels
72-cell panels are essentially 60-cell panels with an extra row of cells (6x12 configuration). This extra row allows them to produce more voltage and more power — usually between 350 to 450 watts.
These panels are commonly used in larger installations, such as:
Commercial rooftops
Solar farms
Utility-scale projects
Due to their larger size and weight, they can be more challenging to handle during installation, but they reduce the total number of panels needed for a given power output, which can lower installation costs.
96-Cell Solar Panels
96-cell panels are a more recent innovation, often used in high-efficiency applications where space is limited but maximum power is needed. These panels often use high-end materials and technologies (such as Panasonic’s HIT cells).
Their higher voltage output can be advantageous in specialized systems but also requires compatible inverters and careful system design.
Pros:
High power density
Excellent for small roofs with high energy demands
Cons:
More expensive
Less standardized
Half-Cut Cells: A Modern Innovation
In addition to traditional full-cell panels, many modern panels use half-cut cells. These panels literally cut each solar cell in half, doubling the number of cells.
For example:
A typical 60-cell panel becomes a 120 half-cell panel
A 72-cell panel becomes a 144 half-cell panel
Benefits of half-cut cells:
Higher efficiency: Reduced resistive losses.
Better shade tolerance: Partial shading affects less of the panel.
Improved durability: Less mechanical stress on each cell.
Even though the number of cells doubles, the panel size remains roughly the same because the cells are physically smaller.
Factors That Influence the Number of Cells
1. Voltage and System Compatibility.
2. Available Space
3. Weight and Installation
4. Efficiency Needs High cell count panels (96-cell or half-cell models for most cases) provide greater efficiency and power per unit area, which is critical in constrained spaces.
Choosing the Right Panel: A Practical Guide
If you're considering a solar energy system, here's a simple guide to help you choose:
For RVs, boats, or tiny off-grid systems: Choose 32-cell panels.
For most residential homes: 60-cell panels (or 120 half-cell panels) are ideal.
For large-scale installations (commercial, utility farms): 72-cell or 144 half-cell panels offer better economics.
For maximum efficiency in limited space: 96-cell panels or advanced half-cut panels are the way to go.
Conclusion
The number of cells in a solar panel sits well above a technical detail — it fundamentally shapes off the panel’s size, voltage, power output, and application. Whether it be a compact 36-cell panel for a remote cabin or powerful 144 half-cell panels for a solar farm, the configuration has to match the project’s needs.
Knowing what cell numbers and shapes mean helps you make wise choices, get the best from your system, and understand better the great tech that drives the future with sun rays.
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