Quick Answer
To create an off-grid solar sizing worksheet, calculate your total daily load, determine your available solar resource, and then select a suitable battery bank and inverter size to meet your energy needs. Consider factors such as panel efficiency, temperature, and shading. Use this data to size your off-grid solar system.
Load Calculation
Calculate your total daily load in watt-hours (Wh) by summing the energy requirements of all your appliances and devices. For example, a refrigerator might require 100 Wh per day, a computer 10 Wh, and a LED light 1 Wh. Use this data to estimate your total daily load and determine the required battery bank size. A general rule of thumb is to size the battery bank for 2-3 days of autonomy.
Panel Sizing
Determine your available solar resource by calculating the total daily solar irradiance in your location. For example, a location with 6 hours of direct sunlight per day and an average irradiance of 200 watts per square meter (W/m^2) would receive 1200 Wh per square meter per day. To size your solar panel array, divide your daily load by the daily solar irradiance, then multiply by the number of hours of direct sunlight per day. For example, if your daily load is 2000 Wh and you have 6 hours of direct sunlight, you would need 100 square meters of solar panels, assuming 200 W/m^2 irradiance.
Inverter and Battery Sizing
Select a suitable inverter size based on your load and panel size. A good rule of thumb is to oversize the inverter by 10-20% to account for inefficiencies and load variations. For example, if your load is 2000 Wh and your inverter is 80% efficient, you would need an inverter capable of 2500 Wh. Choose a battery type and size that matches your load and inverter requirements, taking into account factors such as depth of discharge (DOD), cycle life, and temperature.
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