Changing the Battery Usage through Battery-Backup Systems with Increased Self-Consumption
Qualified person
Adjusting the default values
The parameters for battery usage are set automatically to reasonable values during basic configuration for the respective system. The parameter values can be adjusted if there are special requirements for the system or the battery.
Two ranges can be adjusted seasonally in battery-backup systems with increased self-consumption:
Range for increased self-consumption (MinSlfCsmp)
You determine the percentage of the battery capacity that is to be used for increased self-consumption on the shortest day of the year.
Range for battery-backup function (BURes)
You specify the percentage of the battery capacity that is to be used for the battery-backup function on the longest day.
The longer the days become, the more the SlfCsmp range automatically increases and the BURes range decreases. The range for increased self-consumption reaches its maximum on the longest day. This results in the seasonal progression of the ranges.
Ranges of the battery state of charge as a function of the season for the northern hemisphere (example)
Range | Explanation of the range and parameters | Behavior of the Sunny Island inverter |
|---|---|---|
A | Self-consumption area (SlfCsmp) The SlfCsmp range applies to the shortest day of the year with seasonal adjustment ( > Seasonal Adjustment of the Battery Usage). When seasonal adjustment is deactivated, only the SlfCsmp range is used and the BURes range increased accordingly. | The Sunny Island uses the battery for increased self-consumption. |
Battery > Areas of application > Minimum width of backup power area | ||
B | State of charge conservation area (PVRes) The range size is constant year-round. | Excess PV energy is used for conserving the battery charge. If no excess PV energy is available, the Sunny Island switches to energy saving mode. When the state of charge reaches the BatRes range limit, the Sunny Island charges the battery up to half of the PVRes range from the utility grid. To do so, the Sunny Island charges the battery with maximum efficiency at 25% of the nominal power of the Sunny Island inverter. |
Battery > Areas of application > Area width for conserving battery state of charge | ||
C | Backup power area (BuRes) The BURes range applies to the longest day of the year with seasonal adjustment ( > Seasonal Adjustment of the Battery Usage). When seasonal adjustment is deactivated, only the minimum range is used and the SlfCsmp range increased accordingly. | The Sunny Island uses this range for supplying the battery-backup grid when the utility grid fails. When the utility grid is available again, the battery is charged by the Sunny Island with nominal power from the utility grid. |
Minimum width of backup power area | ||
D | Deep discharge protection area (BatRes) Range for protection against deep discharge This range can only be reached when the utility grid fails. | The Sunny Island is switching to energy-saving mode. The Sunny Island starts up every two hours and attempts to charge the battery with PV energy. If the battery cannot be charged, the Sunny Island switches back to energy-saving mode. When the utility grid is available, the Sunny Island charges the battery with nominal power from the utility grid. |
Battery > Areas of application > Minimum width of deep discharge protection area | ||
E | Deep discharge area (ProtRes) This range can only be reached when the utility grid fails. | When this range is reached, the Sunny Island switches off in order to protect the battery. When the utility grid is available again, the system must be charged manually (see Sunny Island operating manual). |
Battery > Areas of application > Lower lmt deep disch. protect area prior shutdown |
|
Range |
Lead-acid battery |
Lithium-ion battery | ||
|---|---|---|---|---|
|
Shortest day* |
Longest day** |
Shortest day* |
Longest day** | |
|
Self-consumption area |
65% to 100% |
45% to 100% |
30% to 100% |
28% to 100% |
|
State of charge conservation area |
60% to 65% |
40% to 45% |
25% to 30% |
23% to 28% |
|
Backup power area |
15% to 60% |
15% to 40% |
13% to 25% |
13% to 23% |
|
Deep discharge protection area |
10% to 15% |
10% to 15% |
3% to 13% |
3% to 13% |
|
Deep discharge area |
0% to 10% |
0% to 10% |
0% to 3% |
0% to 3% |
* December 21 (northern hemisphere) or June 21 (southern hemisphere)
** June 21 (northern hemisphere) or December 21 (southern hemisphere)
The following ranges result from deactivating seasonal adjustment with the default values of the parameters:
Range | Lead-acid battery | Lithium-ion battery |
|---|---|---|
Self-consumption area | 65% to 100% | 30% to 100% |
State of charge conservation area | 60% to 65% | 25% to 30% |
Backup power area | 15% to 60% | 13% to 25% |
Deep discharge protection area | 10% to 15% | 3% to 13% |
Deep discharge area | 0% to 10% | 0% to 3% |
Procedure for multicluster systems with battery-backup grid
With the Multicluster-Box 12 (MC-Box-12.3-20) and the Grid-Connect-Box, multicluster systems with battery-backup grid can be installed (see Multicluster-Box and Grid-Connect-Box documentation).
- In a multicluster system with battery-backup grid and increased self-consumption, set the ranges of battery state of charge for each cluster to the same values.
- In a multicluster system with battery-backup grid and without increased self-consumption, always set the Internal consumption increase switched on parameter to No.
The basic procedure for changing operating parameters is explained in another section ( > Changing Operating Parameters).
Procedure:
- Select Device > Device > Self-consumption.
- Set the parameter Rise in self-consumption switched on to Yes.
- Select Battery > Areas of application >.
- Set the following parameters for the battery usage:
- Ensure that all battery usage ranges combined result in the value 100%.
Parameter | Value |
|---|---|
Lower lmt deep disch. protect area prior shutdown | – |
Minimum width of deep discharge protection area | Range for protection against deep discharge as a percentage of the battery capacity |
Minimum width of backup power area | Range for the battery-backup function on the longest day of the year as a percentage of the battery capacity The range remains constant year-round when seasonal adjustment is deactivated. |
Area width for conserving battery state of charge | Range for maintaining the state of charge of the battery as a percentage of the battery capacity |
Minimum width of own consumption area | Range for increasing self-consumption on the shortest day of the year as a percentage of the battery capacity When seasonal adjustment is deactivated, this value is used year-round for increased self-consumption. |
Highest-yielding month for battery utilization range: | June profitable for northern hemisphere* |
December profitable for southern hemisphere** | |
Highest-yielding month for battery utilization range: | No for no seasonal adjustment or Yes for seasonal adjustment |
* Set the value to June profitable when June is the month with the highest yield.
** Set the value to December profitable when December is the month with the highest yield.
If the values for the battery usage ranges are incorrect, no adjustment is possible
If all battery usage ranges combined exceed 100%, the parameters for battery usage cannot be set.