SMA SI 4548-US - Manual (Page 113)

SMA America, LLC 13 Battery Management
Operating Manual SI4548-6048-US-BE-en-20 113
are fully recharged. Equalization charging extends the battery life by up to 50%. The automatic
equalization charging function can also be deactivated (parameter "222.12 AutoEquChrgEna",
activated by default) or manually started (parameter "520.01 ChrgSelMan").
13.5.4 Manual Equalization Charge
The parameter "520.01 ChrgSelMan" activates the manual equalization charge on the Sunny Island.
If a generator is connected to the system, it is automatically started and stopped once the equalization
charge is completed.
13.5.5 Silent Mode
In addition to the float charge, the silent mode can only be used (parameter "224.01 SilentEna")
when operating on the utility grid.
The main purpose of the silent mode is to save energy by switching from charge mode to standby
mode in battery-backup systems where the Sunny Island is predominantly in float charge.
The silent mode is activated after the time set for float charge (parameter "224.02 SilentTmFlo") has
expired. The Sunny Island remains in silent mode for a fixed time (parameter "224.03 SilentTmMax")
or until the battery voltage per cell is 0.14 V lower than the set voltage (parameter
"222.10 ChrgVtgFlo"). 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 a stand-alone grid available within
10 ms to 30 ms.
13.6 Battery-Preservation Mode
The Sunny Island has a sophisticated battery-preservation mode. The battery-preservation mode
prevents deep discharge from the battery as far as possible when the energy supply is low, thus
preventing a total system failure as well as damage to the battery.
Change to an equalization charge
If the Sunny Island changes to equalization charge after a specific time of boost charging or full
charging has elapsed, these times are completely considered for the equalization charge.
More than 1% of the nominal battery capacity is discharged
If more than 1% of the nominal battery capacity is discharged during an equalization charge,
50% of the time elapsed is considered for the next constant voltage phase.
External charging device
If an external charger or charge controller is connected to the battery and the criteria for an
equalization charge are fulfilled due to external charging, the Sunny Island treats this as if it had
performed the equalization charge itself.
Carrying out the equalization charge
An equalization charge should be performed at least once a year. After long periods of time
without charging, e.g. in the case of plants which are only operated seasonally, equalization
charges should always be performed manually at the end or at the beginning of the season.