Hi @JavaScript_t,
Please try to avoid opening multiple threads with the same question. We all have questions, and while the community is happy to help, responses may not always be immediate. Patience is appreciated.
Answering your question: There are several factors that can prevent your solar panel from delivering 500 W. The values on the sticker at the back of the panel are determined by the manufacturer under specific testing conditions. You can find these exact conditions in the manual or on the manufacturer’s website. Therefore, the likelihood of actually reaching 500 W in real-world conditions is very low.
However, there are some things you can adjust to maximize your panel’s performance:
Factors you cannot influence
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Weather conditions: Sunlight intensity varies throughout the day and depends on cloud cover, temperature, and atmospheric conditions.
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Season of the year: The sun’s position changes with the seasons, affecting how much energy your panel can generate.
Factors you can influence
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Angle of the solar panel: Adjusting the angle throughout the year helps the panel capture as much direct sunlight as possible, improving efficiency.
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Cable thickness: Using the correct cable size reduces voltage loss. For short distances, 6 mm² (10 AWG) is sufficient; for longer distances, 8 mm² (8 AWG) or 10 mm² (7 AWG) is recommended.
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Cleaning and shading: Keeping the panel clean and ensuring it is not shaded maximizes light absorption and overall power output.
Tip
Adjust the panel’s angle throughout the year (Northern Hemisphere) according to the seasons:
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Winter: November 1st to February 28th
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Spring: March 1st to April 30th
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Summer: May 1st to August 31st
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Autumn: September 1st to October 31st
Note
Calculation for the distance from the panel to the power station
When connecting a solar panel to a power station, the cable length affects voltage loss. Because current travels through both the positive and negative cables, you need to double the cable length in calculations.
Voltage drop (V) = Current (A) × Cable resistance per meter (Ω/m) × (Cable length × 2)
Example using your solar panel specs:
- Panel short-circuit current (Isc): 15.3 A
- Cable thickness: 6 mm² (10 AWG, copper)
- Cable resistance: 0.005 Ω/m (typical for 6 mm² copper)
- One-way cable length: 10 m → total circuit length = 10 × 2 = 20 m
Voltage drop = 15.3 A × 0.005 Ω/m × 20 m = 1.53 V
If your system voltage is 35.1 V (Vmp), this is a voltage drop of 1.53 V / 35.1 V × 100 ≈ 4.36%, which is higher than the recommended 2–3% range. For longer distances or higher currents, a thicker cable would be required to stay within the recommended limit.
Conclusion
At this time of year, achieving 200–250 W is reasonable. By ensuring the panel is fully optimized, you may be able to achieve slightly more power.
Hopefully, this answers your question.
