Battery Management
SMA America, LLC
112
SI5048U-TUS121440
Technical Description
Level 2:
The second level of the battery preservation mode ensures that the Sunny Island is started
regularly every two hours only in the time period during which energy supply is expected, and that it
attempts to charge the battery from the AC side. In case of photovoltaic plants this time is during the
day. In this case, you define the start time using the ”223.03 BatPro2TmStr” parameter and the stop
time using the ”223.04 BatPro2TmStp” parameter.
Level 3:
The third level ensures that the battery is protected from deep discharge and thus against
damage. In this case, the Sunny Island is switched off completely. To start it, see section
9.5 ”Reactivating the Device Following Automatic Shutdown” (page 74).
At all three levels, the Sunny Island is stopped only if no battery current flows within 10 minutes (limit
3A charging current).
The limits for all three levels can be set independently from each other. This allows individual levels to
be skipped.
For level 1 and 2, a hysteresis of 5 % of the SOC charge level is designated for exiting this state.
Battery preservation mode is not automatically exited if an external voltage source
(grid reconnection/generator start) is present.
The battery preservation mode can be exited by manually starting the Sunny Island. If, within
10 minutes (see above) a charging current is detected, the Sunny Island continues to operate;
otherwise, it switches off again.
Parameter BatPro1Soc < BatPro2Soc
If the BatPro1Soc parameter < BatPro2Soc, level 1 is skipped and only level 2 is carried
out.
During inverter operation, the Sunny Island burdens the battery with 25 W. If the Sunny
Island is in standby, only the on-board power supply is fed, which needs approx. 4 W. This
results in a savings of 21 W.
Using the conditions described in level 1 of the battery preservation mode for conversion
purposes and assuming an operation time from 6:00 a.m. to 10:00 p.m., this results in
336 Wh/day. That in turn corresponds to 7 Ah at 48 V and thus 210 Ah per month
(30 days).
