Off-Grid Solar for Beginners — What Size System Do You Actually Need?

Off-Grid Solar for Beginners — What Size System Do You Actually Need? Most off-grid solar guides are written by people trying to sell you a larger system than you need. This one is not. Here is how to size a real system for a modest off-grid homestead. Start With Your Load Before buying anything, calculate daily power consumption in watt-hours. Typical off-grid cabin loads: Item Watts Hours/day Wh/day LED lighting (10 bulbs) 50 5 250 Laptop 45 6 270 Phone charging 10 3 30 Small chest freezer 30 24 720 Water pump (DC) 150 1 150 Fans (2x) 60 8 480 Total 1,900 Wh/day A modest off-grid container home in Missouri uses roughly 1,500 to 2,500 Wh per day without electric cooking or air conditioning. Sizing the Solar Array Missouri gets 4.5 to 5.5 peak sun hours per day on average. Formula: Daily load / peak sun hours / system efficiency = panel watts needed 1,900 Wh / 5 hours / 0.8 (efficiency) = 475 watts of panels minimum Build in 25 to 50 percent margin for cloudy days and winter. A 750W to