SMA SI 5048 - Additional Functions; Load Shedding

Additional Functions SMA Solar Technology AG
88 SI5048-TEN093630 Technical Description
12 Additional Functions
12.1 Load Shedding
The Sunny Island can automatically switch off loads to protect the batteries from deep discharge. To
do this, an external (AC or DC) power contactor must be installed between the Sunny Island and the
loads (see also section 21”Accessories” (page204)).
The graphic shows an example for the settings that minimize the load shedding function at night.
From 6:00 a.m. to 22:00 p.m. the load shedding is activated for a charge state (SOC) of 40 %,
during nighttime (from 22:00 p.m. to 6:00 a.m.), by contrast, the charge state of the battery is allowed
to go down to 30 % before the load-shedding contactor is activated.
The load shedding function can be assigned twice. In the parameters mentioned above, the "Lod1"
part represents the first assigned function and the "Lod2" part represents a second, identical function.
These two load shedding functions, which are dependent on the battery's state of charge, allow for
tiered load shedding in which, by using different SOC values, different priorities can be given to
various load groups.
NOTICE!
Faulty system operation due to lack of load shedding.
• Install external load-shedding protection in case the off-grid system on the
AC-generating side is coupled to PV generators or wind generators.
• If there is overloading due to low energy production or very high energy
consumption, you must be able to switch off loads.
• Always switch off the loads, never the energy generators (e.g., Sunny Boy)!
Lod1SocTm2 Stp Lod1SocTm2 Stp
0h 6h
Lod1Tm1Str Lod1Tm2Str
Lod1SocTm1 Stp
22h 24h
Lod1SocTm2 Str Lod1SocTm2 Str
Lod1SocTm1 Str
t1
t2
t2
30
40
80
Soc [%]