Wizard - Sizing batteries on Grid Connected system

A suitable sizing of the battery bank for a grid connected photovoltaic system allows to storage the energy produced and not self-consumed by the user. Energy that in the absence of the battery storage would be fed into the grid.

There is no unique battery sizing criteria in this case as the designer can search for different targets for energy storage. Depending on battery choice and battery bank size, the program will be able to simulate how the user's energy consumption will be covered between self-consumed energy, from battery and utility grid.

The Consumption distribution explains what is the source, on annual basis, of the percentage of energy needed by the system user. In addition, the values of the energy produced and consumed by the user and the amount of energy exchanged with the utility grid are shown in Result of storage.

If you are not using a profile of electrical consumption for defining the annual consumption, but you are simply assigning the Average Daily Consumption, the calculation of Consumption distribution must be considered as indicative and its reliability is low. It is recommended to use a profile of electrical consumption to have a more accurate result.

If the system is DC-coupled battery storage, it will be necessary to size a charge controller compatible with battery bank and PV field. Compatibility between battery bank and charge controller is verified by:

• Open circuit Voltage < Maximum voltage of charge controller

• Maximum current from PV (short circuit current) < Maximum current capabilities of charge controller

• Maximum power from PV < Maximum operative power of charge controller

• The nominal operative voltage of charge controller = Nominal voltage of battery bank

furthermore if charge controller is Mppt:

Minimum Mppt voltage from PV > Minimum voltage MPP allowed by charge controller

Maximum Mppt voltage from PV < Maximum voltage MPP allowed by charge controller

The program will propose a list of compatible charge controllers among those present in the archive

If the system is AC-coupled battery storage, you need to insert an inverter/charger in the AC section, the compatibility battery bank and inverter/charger is verified by:

• Power of inverter/charger >= Peak power of users consumption

• Battery voltage <= Maximum charging voltage of inverter/charger

• Battery voltage >= Minimum charging voltage of inverter/charger