Calculate your farm’s daily energy usage in watt-hours (Wh) by multiplying your average load (in watts) by the number of hours you need backup power. For example, if your average load is 1000W and you need 5 hours of backup, your requirement is 1000W × 5h = 5000 Wh.

Always include a safety margin—in this guide, we add about 20% to account for inefficiencies. Write down your total energy need as it will serve as the baseline for selecting the right battery size.

Batteries shouldn’t be discharged fully to extend their life. For instance, Renogy LiFePO4 batteries can safely use up to about 80% of their capacity.

To calculate the required capacity, divide your total energy need by the DoD (in decimal form). For a 5000 Wh need and 80% DoD, the adjusted requirement is 5000 Wh ÷ 0.8 = 6250 Wh.

Also factor in any efficiency losses during charging and discharging (typically around 10%) to adjust your energy requirement accordingly.

Renogy offers several battery options with different capacities, such as 1200 Wh, 1800 Wh, 2400 Wh, or 3000 Wh.

Compare your adjusted energy requirement from the previous steps with the available battery capacities and select one that meets or slightly exceeds your need. This ensures you have a buffer for higher energy use or lower charging efficiency days.

Divide your adjusted energy requirement by the capacity of the chosen battery. For example, if you need 6250 Wh and choose a 2400 Wh battery, you would need 6250 ÷ 2400 ≈ 2.6, which rounds up to 3 batteries. Always round up since you cannot install a fraction of a battery.

Consider your farm’s growth potential. Energy needs may increase over time, so it’s wise to choose a battery solution with extra capacity.

Oversizing slightly helps accommodate future loads or days with low solar production. Document your current needs and expected growth to plan for future expansion, ensuring your system remains scalable.