SMA America, LLC
Battery Management
Technical Description
SI5048U-TUS121440
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13.4.5 Silent Mode
In addition to the float charge, the silent mode can be used (”224.01 SilentEna” parameter), only
when operating on the public grid in the operation type ”GridCharge”.
The main purpose of the silent mode is to save energy by switching from charge mode to standby
mode in utility backup systems where the Sunny Island is predominantly in float charge.
The silent mode is activated after the time set for float charge (”224.02 SilentTmFlo” parameter) has
expired. The Sunny Island remains in silent mode for a fixed time (”224.03 SilentTmMax” parameter)
or until the battery voltage per cell is 0.14 V lower than the set voltage (”222.10 ChrgVtgFlo”
parameter). This ensures that the battery is always fully charged, even in silent mode. If a grid failure
is detected during silent mode, the Sunny Island makes an off-grid power system available within
10 ms … 30 ms.
13.5 Battery Preservation Mode
The Sunny Island has a sophisticated battery preservation mode. The battery preservation mode
prevents the battery from being deeply discharged as far as possible when the energy supply is low,
thus, preventing a total system failure as well as damage to the battery.
The battery preservation mode has three levels that are activated as a result of the state of charge
(when the charge drops below the respective limit, parameters ”223.05 BatPro1Soc”,
”223.06 BatPro2Soc” and ”223.07 BatPro3Soc”):
Level 1:
The first level is used to switch the Sunny Island into standby mode at times when the energy
is not necessarily required (e.g., at night). You define the start time using the ”223.01 BatPro1TmStr”
parameter and the stop time using the ”223.02 BatPro1TmStp” parameter.
