Changing the Battery Usage Through Systems for Increased Self-Consumption Without a Battery Backup Grid


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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.

In systems for increased self-consumption, one range can be adjusted seasonally:

  • 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.

The longer the days become, the more the SlfCsmp range increases automatically and the range for protection against deep discharge (BatRes) decreases. The range for increased self-consumption reaches its maximum on the longest day. This results in the seasonal progression of the ranges.

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State of charge ranges of the battery according to the time of year (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 BatRes 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

Deep discharge protection area (BatRes)

This range can only be reached when the utility grid fails. The BatRes range applies to the longest day of the year with seasonal adjustment Seasonal Adjustment of the Battery Usage). If seasonal adjustment is deactivated, the BatRes range is increased accordingly.

If a utility grid is available, the Sunny Island charges the battery using nominal power from the utility grid.

Battery > Areas of application > Minimum width of deep discharge protection area

D

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

The following ranges result from the parameter default values:

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%

10% to 100%

State of charge conservation area

60% to 65%

40% to 45%

25% to 30%

5% to 10%

Deep discharge protection area

10% to 60%

10% to 40%

3% to 25%

3% to 5%

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%

Deep discharge protection area

10% to 60%

3% to 25%

Deep discharge area

0% to 10%

0% to 3%

The basic procedure for changing operating parameters is explained in another section Changing Operating Parameters).

Requirements:

  • The system is not a battery backup system

Procedure:

  1. Select Device > Device > Self-consumption.
  2. Set the parameter Rise in self-consumption switched on to Yes.
  3. Select Battery > Areas of application >.
  4. Set the following parameters for the battery usage:
  5. Parameter

    Value

    Lower lmt deep disch. protect area prior shutdown

    Range for protection during deep discharge as a percentage of the battery capacity

    Minimum width of deep discharge protection area

    Range for protection against deep discharge 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**

    Season operation active

    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.

  6. 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.

    1. Ensure that all battery usage ranges combined result in the value 100%.