Cabin Solar Calculator
List what you want to power, pick your area and how many cloudy days you want to ride out. The calculator estimates the solar panels, battery bank and inverter you need.
| Appliance | Watts | Hours / day |
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Assumptions: 20% system losses (inverter and wiring), panels producing about 75% of their rated power, lithium (LiFePO4) batteries used down to 10% charge. Inverter size assumes everything could run at once, plus a 25% margin. This is a starting estimate, not an electrical design. Have an electrician check any permanent installation.
How to read your results
Energy use per day is the total watt-hours your appliances use in 24 hours, plus 20% for losses in the inverter and wiring. It is the single most important number: everything else is sized from it.
Solar panels needed is the total panel wattage required to refill that energy on a typical winter day in your area. Panels rarely deliver their full rated power, so the calculator assumes about 75% of the label value.
Battery bank is sized to cover your chosen number of days without sun, using lithium iron phosphate (LiFePO4) batteries that can safely be used down to about 10% charge.
Inverter converts battery power to household AC. It must handle everything that might run at the same time. Motors (pumps, fridges, power tools) can briefly draw several times their running watts when they start, so check the surge rating too.
Want the full method, step by step? Read How Much Solar Do I Need for a Cabin?