Solar Panel Sizing Calculator
Calculate the solar panel wattage needed to charge a battery or run a load given daily energy needs and sun hours.
Wh
hours
%
Required Panel Wattage
13.3 W
Panel Current (12V system)1.11 A
Daily Generation66.7 Wh
Required Panel Wattage vs Daily Energy Needed
Solar Panel Sizing
Formula
Panel Watts = Daily Energy / (Sun Hours x Efficiency)
Efficiency accounts for charge controller losses, wiring, temperature derating, and panel degradation. Typical system efficiency is 70-80%.
Example Calculation
50 Wh daily energy need, 5 peak sun hours, 75% system efficiency.
- 01Required generation = 50 / 0.75 = 66.7 Wh
- 02Panel watts = 66.7 / 5 = 13.3 W
- 03At 12 V: current = 13.3 / 12 = 1.11 A
Frequently Asked Questions
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