7 Commissioning
SMA Solar Technology AG
Operating manual
SI44M-80H-13-BE-en-15
84
7.6.6
Changing the Battery Protection Mode in Off-Grid Systems
Relevant for off-grid systems
The basic procedure for changing operating parameters is explained in another section (see Section 8.6, page 113).
Function of the battery protection mode:
The battery protection mode protects the battery.
If the state of charge (SOC) of the battery falls below the thresholds, battery protection mode is activated. In battery
protection mode, the Sunny Island switches to energy-saving mode or switches itself off. The battery protection mode
has 3 levels. 1 state of charge threshold can be set for each level. Level 1 and 2 of the battery protection mode have
specific start and end times and are therefore dependent on the time of day (see Section 8.12.2, page 117).
• Level 1
If the state of charge falls below the threshold for level 1, the Sunny Island switches to energy-saving mode
between the start time and end time. This way you can specify preferred times for the Sunny Island to be switched
off if an energy deficit occurs.
• Level 2
If the SOC drops below the threshold for level 2, the Sunny Island switches to energy-saving mode. Use the start
time and end time to define the time window in which no energy is anticipated from AC sources. Outside this time
window, the Sunny Island starts up every 2 hours to charge the battery. If no energy is available to charge the
battery, the Sunny Island remains on energy-saving mode.
This means that, for example, in stand-alone grids with PV inverters, you can specify that the Sunny Island does not
start up at night, preventing it from consuming energy from the battery.
• Level 3
If the state of charge falls below the threshold for level 3, the Sunny Island switches itself off. This protects the
battery against deep discharge and severe damage. To charge the battery again, the Sunny Island must be
switched on and started manually.
At all 3 levels, the Sunny Island will only switch to energy-saving mode or switch itself off if no charging current has
flowed in the battery for at least 5 minutes.
Recharging the battery with an external energy source:
In levels 1 and 2 of battery protection mode, you can charge the battery at any time with an external energy source. If
a voltage is present on connection
AC2
, the Sunny Island exits the energy-saving mode.
If the Sunny Island has switched to level 3 of battery protection mode by itself, you must charge the battery in
emergency charge mode (see Section 13.6, page 131).
Time settings:
The start time and the end time can be configured for battery protection mode levels 1 and 2.
If the state of charge falls below the threshold for level 1, the Sunny Island switches to energy-saving mode between
the start time and end time.
If the state of charge falls below the threshold for level 2, the Sunny Island switches to energy-saving mode between
the start time and end time. The Sunny Island attempts to charge the battery in the remaining time.
Procedure:
1. Select
Battery > Protection mode
.
2. Set the parameter
Start time of battery protection mode
to the desired start times for level 1 and 2.
3. Set the parameter
End time of battery protection mode
to the desired end times for level 1 and 2.
4. Set the parameter
Battery state of charge for protection mode
to the desired SOC threshold for level 1, 2
and 3.
