How do I size a battery energy storage system?

Properly sizing a battery energy storage system involves a thorough assessment of your energy needs, understanding the system’s purpose, and considering factors like capacity, DoD, efficiency, and future expansion. By following these guidelines, you can ensure your BESS provides optimal performance, reliability, and cost savings.

What size battery do I Need?

Regardless, if you already have a 5kW system, or are looking to purchase one, you’ll likely need a battery with a capacity of at least 10kWh, more likely, up to 13.5 kWh. The exact battery size you need depends on how much electricity you typically consume during daylight hours and your purchase motives.

How big should a solar battery be?

This is the best way to size a battery for existing solar owners, as the financials dictate what size you need based on your electricity usage habits. Regardless, if you already have a 5kW system, or are looking to purchase one, you’ll likely need a battery with a capacity of at least 10kWh, more likely, up to 13.5 kWh.

What are the best solar batteries for a 5kW system?

Due to the popularity of system sizes around 5kW and 6.6kW, some of the best solar batteries are geared to serve systems of this size. The Tesla Powerwall 3, BYD battery and SunGrow batteries are all suitable options for a 5kW system. You can read our review of the Tesla Powerwall 3 here.

How much power does a battery system need?

For example, if your critical loads require 2,000 watts of power and you need backup power for 24 hours, your total load would be 48,000 watt-hours (2,000 watts x 24 hours). Once you have determined your total load, you can select a battery system that can meet your power needs.

What is battery storage system sizing?

Battery storage system sizing is significantly more complicated than sizing a solar-only system. While solar panels generate energy, batteries only store it, so their usability (as well as their value) is based first and foremost on the energy available to fill them up (which usually comes from your solar panels).