Quick Answer
To size a solar panel system for off-grid RV living, calculate the daily energy needs, determine the available roof space, and choose a system that meets both requirements. A general rule of thumb is to size the system to provide 20-30% of the daily energy needs. This allows for some reserve energy during periods of low sunlight.
Assessing Daily Energy Needs
To determine the daily energy needs of your RV, calculate the total watt-hours (Wh) required per day. Multiply the total daily energy needs by 1.3 to account for inefficiencies in the system. For example, a 30-amp RV with a refrigerator, lights, and appliances might require 1000 Wh/day. To size the system, multiply 1000 Wh/day by 1.3, resulting in 1300 Wh/day. Convert this number to kilowatt-hours (kWh) by dividing by 1000, yielding 1.3 kWh/day.
Choosing the Right Solar Panel Size
Determine the available roof space for the solar panels, taking into account obstructions and shading. Consider a 4’ x 8’ (32 sq ft) or 4’ x 10’ (40 sq ft) panel size, depending on your roof space limitations. Multiply the total available roof space by the number of panels you can fit to determine the total wattage. For example, 32 sq ft of roof space with 4 panels of 200W each yields a total system size of 800W. Be sure to account for any inefficiencies in the system, such as panel efficiency and wiring losses.
System Sizing Example
To illustrate solar panel sizing for an RV, consider a system with 800W of solar panels, a 200Ah battery bank, and a 30-amp charge controller. This system should provide 1300 Wh/day of energy, assuming 25% efficiency in the system. To calculate the daily solar panel output, divide the total system size by 1.3 (accounting for inefficiencies) and multiply by 5 (accounting for 5 hours of direct sunlight). This results in approximately 495 Wh of solar panel output per hour of direct sunlight.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.