SMA SUNNY BOY STORAGE 3.8-US Instructions D'installation page 22

4 Product Overview
be manually enabled in the event of a grid failure, and must also be disabled again once the utility
grid is available (information in terms of switching operations of the automatic transfer switch and
procedures during grid failure and grid reconnection see planning guidelines "SMA Energy System
Home with Battery-Backup Function").
When the utility grid is down and the battery fully discharged, there is, in the beginning, not enough
power available to create a stable battery-backup grid. In this case, the battery must be charged by
the PV system. The battery inverter is able to create a stable battery-backup grid only when enough
power is available in the battery. To use battery charging power from the PV system, the battery
inverter has to create a stand-alone grid. For this purpose, the battery inverter requires energy from
the battery reserve. If enough PV power is available, the PV inverters start automatically and the
battery is charged with energy from the PV system. The battery is charged with energy until the
battery inverter is able to provide a battery-backup grid. By setting parameters, it is possible to
define up to which state of charge the battery is charged and discharged. If not enough PV energy
is available to start the PV inverters, the stand-alone grid breaks down. The battery inverter makes
another attempt to start the PV inverter 2 hours later to charge the battery with energy from the PV
system. If the battery inverter still fails to create a stand-alone grid after several attempts due to
insufficient PV energy, the battery inverter and battery switch to sleep mode. In this case, a manual
black start is required to switch the battery inverter and battery from sleep mode back to operation.
No secure power supply operation possible in the SMA Energy System
Home with Battery-Backup Function
If the inverter is used in an SMA Energy System Home with battery-backup function and
connected with an automatic transfer switching device, the secure power supply operation is
not available.
Do not connect any loads that require an uninterrupted energy supply
The secure power supply operation and the battery-backup operation may not be used for
loads that require a uninterrupted energy supply. The energy that is available during the
secure power supply operation or battery-backup operation depends on the battery capacity
available and the state of charge of the battery (SOC).
• Do not connect loads if they are dependent on an uninterrupted energy supply for
reliable operation.
Black start function
The inverter has a black start function and an auxiliary battery that provides energy for the black
start. In battery-backup systems, you have the possibility to install a standard switch for black
starting the inverter and battery. The black-start switch is used to start the battery-backup operation
manually in the event of grid failure if the battery and inverter are in sleep mode and, therefore, are
unable to provide energy. When the black-start switch is switched on manually, the energy from the
auxiliary battery is made available in order to automatically switch the battery and therefore also
the inverter from sleep mode to operation in order that the inverter can make energy available from
the battery. You can stop the battery-backup operation by switching it off manually. To enable the
black-start function, at least one battery capable of black start must be connected to input A.
22 SBSxx-US-10-IA-xx-14
SMA Solar Technology AG
Installation Manual