Sizing Your Off-Grid System
Get Optimal Energy Efficiency
Sizing Your Off-Grid System
Get Optimal Energy Efficiency
#1 Ensure your inverter can handle your simultaneous loads
- Identify your highest AC loads in watts (e.g., 6,000 watts). Given that inverters typically have a 50% surge rate, a 4,000-watt inverter will suffice.
- Make sure the total connected AC wattage at any given time is lower than the inverter's rating. This ensures reliable operation and prevents overload situations.
Measure Your Appliance Load
To find out more about calculating appliance loads, click here.
#2 Ensure you have sufficient battery storage for 1 – 2 days
This typically equates to about 70% of your total kilowatt-hour (kWh) storage capacity for lithium batteries, and approximately 50% for lead carbon batteries.
Calculate your corrected watt-hours per day.
For example, if you require 5,000 watt-hours per day, divide by 0.7 for lithium batteries or 0.5 for lead carbon batteries to determine the necessary battery capacity. In this case, you would need approximately 7,143 watt-hours (7.14 kWh) of lithium battery capacity or 10,000 watt-hours (10 kWh) of lead carbon battery capacity. This ensures you have sufficient backup power to maintain operations during periods of low solar production or when grid power is unavailable.
#3 To determine the solar array size required
Calculate your corrected watt-hours per day. Divide this number by an average of 3 sun hours per day to estimate the array size needed.
For example, if your corrected watt-hours per day is 5,000 watts, dividing by 3 sun hours per day gives you 1,666.67 watts. This is the minimum size solar array needed under ideal conditions with good southern exposure and no shading.
If there is shading present, adjustments will be necessary to ensure adequate solar production.