Is there a formula for calculating daily energy needs off-grid?

Calculating Daily Energy Needs

To size an off-grid solar system, you need to calculate the total daily energy required by your appliances and loads. This can be done by multiplying the power rating of each appliance by the number of hours it’s used per day, then summing the results. For example, a 500W refrigerator used for 12 hours a day would require 6 kWh (500W x 12 hours).

Load Calculation Worksheet

Create a load calculation worksheet to organize your data. List all appliances and loads, their power ratings, and the number of hours they’re used per day. Then, multiply each power rating by the usage hours and sum the results to get the total daily energy required. For example:

• Refrigerator: 500W x 12 hours = 6 kWh
• Lights: 100W x 8 hours = 0.8 kWh
• Computer: 200W x 4 hours = 0.8 kWh Total daily energy required: 7.6 kWh

Sizing the Solar System

Once you have the total daily energy required, you can use this number to size your solar panel, battery, and inverter system. A general rule of thumb is to oversize the system by 10-20% to account for energy losses and inefficiencies. For example, if you require 7.6 kWh per day, you may want to size your system to produce 8-9 kWh per day.