Off-grid Solar System Sizing Calculator

Harnessing solar power for off-grid applications isn’t just about placing panels under the sun. It demands precise calculations to ensure energy reliability and system longevity. At the center of this intricate setup is the Off-grid solar sizing calculator—an indispensable tool for technicians and renewable energy enthusiasts. Checkout our User Guide

01.Enter the Appliances

Device Watts (W) Hours (h) Watt Hours (Wh)

02.Select System Voltage

03.Days of Autonomy


04.Select Degree of Discharge


05.Select Efficiency


06.Avg Sun Hours Per day


Understanding and Utilizing the Off-grid Solar Sizing Calculator | User Guide

Understanding the Input Fields

The Off-grid solar sizing calculator relies on several inputs, each critical in determining the specifications of your solar system:

Enter the Appliances: It's vital to quantify the daily energy consumption of each appliance. This isn't just about their power rating (in watts) but also the duration they're active. By aggregating these, the calculator derives the total daily power demand in watt-hours (Wh).

Select System Voltage: System voltage, typically 12V, 24V, or 48V, determines the configuration of your battery bank. A higher voltage system can reduce transmission losses and cable sizes, but compatibility with appliances and inverters is paramount.

Days of Autonomy for the System: This denotes how many consecutive days your system should support without solar input—essential for regions with extended cloudy or rainy spells. The more days of autonomy you want, the more storage capacity you'll need.

Select Degree of Discharge for the Batteries: Batteries have an optimal discharge level to maximize their lifespan. For instance, regularly discharging a lead-acid battery beyond 50% can shorten its life. The calculator considers this to suggest an appropriate battery size.

Select Efficiency of the Inverter: No inverter is 100% efficient. If an inverter has 90% efficiency, it means 10% of the energy is lost during the DC to AC conversion process. This efficiency factor is crucial in estimating actual power delivery.

Avg Sun Hours Per Day: This technical input considers the peak sun hours—hours during which solar irradiance averages 1,000 watts per square meter. It's a pivotal factor in gauging the solar panel capacity required for your location.

Understanding the Output Fields

Post data input, the Off-grid solar sizing calculator churns out key metrics:

Total Daily Watt-hours: A culmination of your energy needs, this figure represents the aggregate energy all appliances consume daily.

Required Battery Capacity for the System: By factoring in consumption, inverter efficiency, days of autonomy, and battery discharge levels, the calculator stipulates the necessary battery capacity, usually in ampere-hours (Ah).

Required Solar Panel Capacity for the System: Based on daily consumption and average sun hours, it calculates the total photovoltaic capacity needed. This determines the number and size of solar panels for your setup.

Utilizing the Off-grid solar sizing calculator isn't just a step—it's an imperative phase in off-grid solar installations. By understanding its technical underpinnings, one ensures a system that's both efficient and enduring. Knowledge, as they say in the solar world, truly illuminates. Checkout our Complete Guide on Component Selection