SMA SI 4548-US - Manual (Page 107)

SMA America, LLC 13 Battery Management
Operating Manual SI4548-6048-US-BE-en-20 107
13 Battery Management
13.1 Battery Type and Minimum Battery Capacity
The battery management of the Sunny Island supports the following three battery types (parameter
"221.01 BatTyp"):
Lithium-ion batteries have an own battery management. The battery management of the lithium-ion
battery communicates with the Sunny Island via data cables.
The battery capacity (parameter "221.02 BatCpyNom") is to be entered as the nominal capacity for
a 20 hour discharge (C20). If this information is not available from the battery manufacturer's
datasheet, it can be calculated from the data for different discharge times (120 h, 100 h, 20 h, 5 h,
1 h) in the following manner:
SMA recommends the following minimum battery capacities:
• Minimum battery capacity per Sunny Island inverter:
– Sunny Island 4548-US: 190 Ah
– Sunny Island 6048-US: 250 Ah
• Minimum battery capacity per 1 kW output power of the PV system: 100 Ah (C20)
The Sunny Island is designed and preset for a nominal battery voltage (parameter
"221.03 BatVtgNom") of 48 V (24 cells for every 2 V) with lead-acid batteries (FLA and VRLA) and
45.6 V (38 cells for every 1.2 V) with nickel-cadmium batteries.
FLA Flooded Lead Acid: valve-regulated lead-acid battery with liquid
electrolyte in all standard designs available on the market (grid plate,
tubular plate, small, large, etc.).
VRLA Valve Regulated Lead Acid: Closed lead acid batteries with immobilized
electrolyte in gel or AGM (Absorbent Glass Mat Separator) in all standard
designs available on the market (grid plate, tubular plate, small, large,
AGM, gel, etc.)
NiCd Nickel Cadmium: Sealed pocket-type plate or fiber plate nickel-cadmium
batteries.
C20 C120/1.18 C20 C10/0.92
C20 C100/1.15 C20 C5/0.81
C20 C20 C20 C1/0.57
Failure of individual battery cells
If individual battery cells fail over several years of continuous operation, the nominal voltage
can be set in the range from 42 V to 48 V. Up to three individual cells can be removed and the
plant can still continue to operate.