Changing the Battery Usage Regarding Battery-Backup Systems with Increased Self-Consumption
Qualified person
Ranges for battery use:
2 ranges can be adjusted seasonally in battery-backup systems with increased self-consumption:
Increased self-consumption range (SlfCsmp)
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 range (SlfCsmp)1) 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 > Ranges of application > Minimum width of backup power range | ||
B | State of charge conservation range (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 > Ranges of application > Width of the range for conserving battery state of charge | ||
C | Backup power range (BuRes)1) 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 range | ||
D | Deep discharge protection range (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 2 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 > Ranges of application > Minimum width of deep discharge protection range | ||
E | Deep discharge range (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. |
Battery > Ranges of application > Lower lmt deep disch. protect range prior shutdown |
1) This range can be adjusted for all battery types.
The following ranges result from the parameter default values:
Range | Lead-acid battery | Lithium-ion battery | ||
|---|---|---|---|---|
Shortest day1) | Longest day2) | Shortest day1) | Longest day2) | |
Self-consumption range | 65% to 100% | 45% to 100% | 30% to 100% | 28% to 100% |
State of charge conservation range | 60% to 65% | 40% to 45% | 25% to 30% | 23% to 28% |
Backup power range | 15% to 60% | 15% to 40% | 13% to 25% | 13% to 23% |
Deep discharge protection range | 10% to 15% | 10% to 15% | 3% to 13% | 3% to 13% |
Deep discharge range | 0% to 10% | 0% to 10% | 0% to 3% | 0% to 3% |
1) December 21 (northern hemisphere) or June 21 (southern hemisphere)
2) 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 range | 65% to 100% | 30% to 100% |
State of charge conservation range | 60% to 65% | 25% to 30% |
Backup power range | 15% to 60% | 13% to 25% |
Deep discharge protection range | 10% to 15% | 3% to 13% |
Deep discharge range | 0% to 10% | 0% to 3% |
Parameters for battery use:
Procedure for multicluster systems with battery-backup grid
All systems for which VDE-AR-N 4105-11:2018, EN50549-1:2018, C10/11:2019, G98-1:2018, G99-1:2018, CEI 0-21:2019 type A/type B, TOR generator type A of the European grid connection regulations according to Regulation (EU) 2016/631 are subject shall not be set up as multicluster systems.
Multicluster systems with battery-backup grid can be set up with the Multicluster-Box 12 (MC-Box-12.3-20) and the Grid-Connect-Box (see documentation of the Multicluster-Box and Grid-Connect-Box). When doing so, always perform the following steps:
- 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.
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.
- Ensure that all battery usage ranges combined result in the value 100%.
The basic procedure for changing operating parameters is explained in another section ( > Changing Operating Parameters).
Parameter | Value |
|---|---|
Lower lmt deep disch. protect range prior shutdown | – |
Minimum width of deep discharge protection range | Range for protection against deep discharge as a percentage of the battery capacity Within this range, the system goes into energy-saving mode and automatically attempts to recharge the battery from available PV energy. |
Minimum width of backup power range | 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. |
Width of the range 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 range | 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 hemisphere2) |
December profitable for southern hemisphere3) | |
Highest-yielding month for battery utilization range: | No for no seasonal adjustment or Yes for seasonal adjustment |
2) Set the value to June profitable when June is the month with the highest yield.
3) Set the value to December profitable when December is the month with the highest yield.
Procedure:
- Select Device > Device > Self-consumption.
- Set the parameter Rise in self-consumption switched on to Yes.
- Select Battery > Ranges of application >.
- Set the parameters for battery use.