Polycrystalline solar cell 3"x6" or 78x156mm with 3BB
78x156 mm (3x6 inch) polycrystalline solar cell rated 2.25-2.33 Wp with 3 busbars. Nominal values: Vmp 0.544 V, Imp 4.22 A, Voc 0.64 V and 18.7% efficiency.
The rectangular format suits narrow modules, prototypes, compatible repairs and STEM labs. This is a bare cell and requires ribbon, soldering, support and encapsulation.
The 78x156 mm 3BB polycrystalline solar cell delivers 2.25-2.33 Wp in a rectangular format for narrow modules, prototypes and educational demonstrators. Its nominal voltage remains approximately 0.544 V at maximum power, while current is 4.22 A because the active area is about half that of a 156x156 mm cell.
It is not a complete panel. A module requires ribbon compatible with three busbars, controlled soldering, mechanical support, insulation, a transparent front layer, backsheet and encapsulation.
Why choose the 78x156 mm format?
The elongated geometry supports narrow panel layouts and spaces where a full square cell will not fit. It also provides lower current than a 156x156 mm cell while retaining a similar voltage per element, making it useful for experiments comparing active area and current.
For repairs, technology, dimensions, current, busbar count and electrical characteristics must match. A 78x156 mm cell is not an automatic substitute for a full cell or a different busbar design.
SC1P3-78x156 technical specifications
| Reference | SC1P3-78x156 |
| Technology | Polycrystalline silicon |
| Rated power Pmax | 2.25-2.33 Wp |
| Vmp | 0.544 V |
| Imp | 4.22 A |
| Voc | 0.64 V |
| Isc | 4.99 A |
| Nominal efficiency | 18.7% |
| Busbars | 3BB |
| Dimensions | 78x156 mm, about 3x6 inches |
| Thickness | 170 ± 20 µm |
| Weight | About 7 g |
What do 12, 24 or 36 cells in series produce?
Series connection adds voltage while current remains approximately 4.22 A. Values are theoretical before temperature, mismatch, ribbon and encapsulation losses.
| Cells | Vmp | Voc | Approximate power |
| 12 | 6.53 V | 7.68 V | 27.0-28.0 Wp |
| 24 | 13.06 V | 15.36 V | 54.0-55.9 Wp |
| 36 | 19.58 V | 23.04 V | 81.0-83.9 Wp |
Select the cell count from the voltage required by the load or charge controller. To increase current, connect complete matched strings in parallel with suitable wiring and protection.
STEM projects and educational photovoltaic kits
The 78x156 mm format is ideal for comparing half the active area with a 156x156 mm cell: voltage remains similar while current falls with area. This provides a practical lesson in series, parallel, irradiance and power.
Discover The Sun in the Classroom and MR WATT educational photovoltaic kits
How to solder the 3BB cell
Use ribbon and flux suitable for the three busbars, controlled temperature and short contact times. Do not bend or press the wafer. Check continuity, polarity and voltage after each string.
Read the MR WATT solar-cell soldering guide
Frequently asked questions
Is this half of a 156x156 mm cell?
Its nominal size is 78x156 mm, about half the active area of a 156x156 mm cell. Voltage is similar, while nominal current is lower.
Is this a complete solar panel?
No. It is one 2.25-2.33 Wp cell and requires interconnections, support, insulation and encapsulation.
How many cells provide roughly 18 V nominal?
Thirty-six cells in series provide about 19.58 V Vmp and 23.04 V Voc before losses and temperature effects.
Can it repair an existing panel?
Only when format, technology, current, busbars and electrical data match the original cells.
Can it be used outdoors without protection?
No. The bare cell must be encapsulated and protected from moisture, impact and mechanical stress.
