To calculate needed solar capacity, use this formula: (Daily Ah consumption ÷ 5 hours) × 12 volts = minimum watts needed. Most would install 400W+ to account for less-than-perfect conditions and battery charging. So, you need to figure out how many electrical loads (or appliances) you will have, and how many amps each appliance will draw. This information can be found in the product manual or on the label of every device. This. This tool is designed to help you estimate your daily energy consumption for off-grid setups such as cabins, RVs, tiny homes, or remote solar systems. Whether. Widely one kilowatt of solar setup involves around 100 square feet and generates roughly 1,100 kWh yearly. For a typical home one needs between 16 and 23 solar panels to cover whole electricity use. Multiply amps × hours to get amp-hours (Ah). Start by adding up the wattage of everything you want to run, like refrigerators, lights, laptops, or medical equipment, and choose a solar generator that can handle both the running watts and the.