Solar Panel Sizing Calculator
Use this solar watt calculator to find out how many watts of solar panels you need to recharge your power station within a single day, based on your battery capacity, location, peak sun hours, and real-world losses.
Power Station Capacity
Location & Conditions
Panel Size
Your System
Recommended panels
minimum total panel wattage
Based on 2.5 peak sun hrs in UK / Northern Europe, fixed flat on ground / roof (typical), 85% system efficiency.
How it works
- • Peak sun hours is the number of hours a day when irradiance averages ≥ 1000 W/m².
- • Panels produce their rated wattage only in ideal conditions. Real-world output is lower.
- • MPPT charge controllers are the most efficient — budget PWM controllers lose ~20%.
- • Always oversize panels slightly; more watts = faster recharge & cloudy-day resilience.
- • Check that your power station's max solar input isn't exceeded by your panel array.
Know your solar wattage? Now size your battery.
Use our Power Station Sizing Calculator to figure out exactly how many watt-hours of storage you need, then compare real prices.
Solar Wattage Calculator FAQ
Quick answers on sizing solar panels for a portable power station.
How do I calculate my solar wattage needs?▾
Divide the watt-hours you need to replace by your location's peak sun hours, then divide again by system efficiency. For example, replacing 800Wh with 4 peak sun hours at 85% efficiency means roughly 235W of panels. Use the calculator above for a tailored result.
How many solar panels do I need for a power station?▾
It depends on the battery capacity, the panel wattage, and your peak sun hours. The calculator above shows the minimum total panel wattage and how many panels of a given size you need. Always check the station's maximum solar voltage and current limits too.
What is a solar watt calculator?▾
A solar watt calculator (also called a solar wattage calculator) converts your battery capacity, location, and recharge window into the watts of solar panels you need. It accounts for peak sun hours and real-world charging losses.
How many watts of solar panels do I need for camping?▾
Most campers need a folding panel in the 100–200W range for a small to mid-size station, but the right size depends on your battery and how fast you want to recharge. Enter your setup above for a specific number.
Why is real-world solar output lower than the panel rating?▾
Panel ratings are measured under ideal lab conditions. Cloud, heat, shade, panel angle, cable length, and the station's charge controller all reduce real output, which is why the calculator applies an efficiency factor.
The solar math, in one line
Energy to restore (Wh) = Battery capacity × Target state of charge
Panel watts needed = Energy to restore ÷ (Peak sun hours × System efficiency)Peak sun hours vary by region and season. For a detailed estimate, use NREL's PVWatts calculator, and always check the station's maximum solar input voltage and current before connecting panels.
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