List the essential loads
Create a list of appliances that need backup power. Record their power demand and expected operating time. Separate essential loads from optional ones so that the battery sizing exercise reflects the intended use. Whole-home backup is different from supporting lights, communications and a refrigerator.
Calculate a first energy estimate
Energy in kWh equals power in kW multiplied by time in hours. A hypothetical 0.8kW average load operating for six hours needs 4.8kWh at the load. Actual battery sizing must also account for system losses, reserve settings and the amount of the battery’s nominal energy that the design permits you to use.
Distinguish nominal and usable energy
A 51.2V 200Ah pack has 10.24kWh of nominal energy by calculation. That does not mean the connected loads receive 10.24kWh in every operating condition. Ask for the usable-energy specification and the inverter efficiency assumptions that apply to your system.
Check output power and recharging
The battery and inverter must support both sustained loads and startup demand. Energy capacity alone is not sufficient. Also review the available solar production or other charging source, the allowed charge current and the time available to recharge between periods of use.
Build a complete project brief
Send the inverter model, required backup duration, load list, installation location and any space constraints. Yinan’s residential catalog lists 8.448kWh, 10.24kWh and 15.36kWh configurations. The final selection should be reviewed with the system designer and installer for your intended application.
Further Reading
Victron Energy: Battery system design and BMS selection guide
Explore Yinan battery solutions or send your application requirements.