Why Off Grid Sizing Matters
An off grid solar system must balance energy use, storage, and sunlight. A small design causes low battery voltage and early shutdowns. An oversized design costs more than needed. This calculator helps compare daily loads with panel output, battery reserve, inverter demand, and controller current.
Daily Energy Planning
Start with the devices that run each day. Enter watts, quantity, use hours, and duty cycle. The tool converts those values into watt hours. Duty cycle helps with fridges, pumps, and tools that do not run continuously. Extra daily energy can also be added for unknown loads.
Battery Storage
Battery sizing uses autonomy days and depth of discharge. Autonomy is the number of cloudy days the system should survive. Depth of discharge is the usable battery percentage. A lower discharge limit protects batteries and extends service life. Inverter efficiency is included because AC loads need conversion.
Solar Array Estimate
Panel sizing depends on daily energy, peak sun hours, future growth, and system losses. Losses can include heat, dust, wiring, controller conversion, and battery charging. The calculator turns the needed array size into a practical panel count using the selected panel wattage.
Inverter And Controller
The inverter should cover expected running power and surge demand. Motors and compressors can surge above normal wattage. A headroom value provides added safety. Charge controller current is estimated from array watts and battery voltage. The selected safety margin helps avoid undersized controller ratings.
Using The Results
Use the result as a planning guide. Local weather, shading, cable length, battery chemistry, and installation rules still matter. For final projects, verify equipment limits and follow qualified electrical advice. Export the CSV or PDF summary to compare options and keep design notes.
Design Checks
Review every result before buying parts. Check whether the battery bank matches the inverter voltage. Confirm the controller accepts the panel string voltage. Leave space for future appliances. Consider seasonal sun changes. Winter usually needs more panels or less load. Also check cable size, fuses, breakers, ventilation, and mounting direction. A careful design reduces outages and improves safety. It also makes upgrades easier later. Record assumptions, because each location changes power production and reserve needs. Recheck loads again after real use.