Battery Management
SMA Solar Technology AG
124
SBU2200-TEN083320
Technical Description
16.2 Start Options
If the battery is replaced in a system, the battery management system must be restarted and
reconfigured. This can be done using the "Quick Configuration Guide QCG" (see section
10.2 „Starting the Quick Configuration Guide (QCG)“ (87)).
16.3 State of Charge/SOC and SOH
The Sunny Backup 2200 has a very precise internal charge level calculation (display value "120.01
BatSoc"). The operation for calculating the charge level is based on balancing the ampere hours. This
means: all currents flowing in and out of the battery are added together and based on the nominal
capacity. In order to take into consideration faults caused by self discharge and charging losses
caused by gassing, these losses are already internally omitted. Unlike other operations, no fixed
charging factor must be set.
When the fully charged state is reached, the charge state value is set back to 90 %, 95 % or 100 %,
depending on how full the battery was actually charged. If the default settings are not changed, a
charge state of 90 % is normally reached after a boost charge; a charge state of 95 % is normally
reached after a full charge, and a charge state of 100 % is normally reached after an equalization
charge.
Since fully charged states are only rarely achieved during a grid failure, the operation used here can
also utilize the battery voltage during constant discharge phases with low discharge currents to
recalibrate the charge state. Compared to the ampere hour balancing method, the operation used
here exhibits a high level of stability over the long term when recalibrated at regular intervals.
Both the ampere hour balancing method and the recalibration procedure, which is performed via the
voltage, automatically adjust to the connected battery over time (depends on the number of grid
failures).
The estimated charge state error (display value "120.11 BatSocErr") will provide you with continuous
information on the accuracy of the battery charge state currently calculated. The average error will
continuously diminish as the adjustment to the actual battery increasingly improves.
Only when the battery is new does its usable capacity correspond to the capacity specified by the
battery manufacturer. As the battery ages and as a result of frequent insufficient charging, the
battery’s useable capacity may decrease considerably on a permanent or only a temporary basis.
NOTICE!
Damage to battery due to incorrect measurement of battery temperature.
If the battery temperature sensor is missing or defective, the Sunny Backup 2200 will
assume the battery temperature is 40 °C and continue running. Over time this leads to
insufficient battery charging.
• Note the relevant warning messages of the Sunny Backup 2200.
• Connect the battery temperature sensor.
• Replace the defective battery temperature sensor.
