Battery Section¶

Battery Section is an advanced element that provides direct access to the model layer Battery element. Unlike the standard Battery element which creates multiple sections and an internal node, this element creates a single battery section that must be connected manually via Connection elements.

For mathematical details, see Battery Section Modeling.

Configuration¶

Overview¶

A Battery Section element represents:

• Single battery section with capacity and initial charge
• No implicit connections - must be connected explicitly via Connection elements
• Direct model access - maps directly to the model layer Battery element without additional composition

Unlike the standard Battery element, Battery Section does not create:

• Multiple SOC sections (undercharge, normal, overcharge)
• Internal node for power routing
• Implicit connections to other elements

You must manually create Connection elements to connect the Battery Section to your network.

Configuration Fields¶

Name¶

Choose a descriptive, friendly name. Home Assistant uses it for sensor names, so avoid symbols or abbreviations you would not want to see in the UI.

Capacity¶

Select a Home Assistant sensor that reports the battery capacity in kWh. The sensor can provide a constant value or a forecast with time-varying capacity.

The optimizer uses this value to enforce state of charge constraints.

Initial Charge¶

Select a Home Assistant sensor that reports the initial energy stored in the battery in kWh. This represents the battery's state of charge at the start of the optimization window.

The sensor should provide a single current value (not a forecast).

Configuration Example¶

Basic battery section configuration:

After creating the Battery Section element, you must create Connection elements to connect it to other elements in your network (nodes, grids, etc.).

Sensors Created¶

A Battery Section element creates 1 device in Home Assistant with the following sensors.

Power Charge¶

The optimal power being charged into the battery at each time period. Values are always positive or zero.

Example: A value of 3.5 kW means the battery is charging at 3.5 kW at this time period.

Power Discharge¶

The optimal power being discharged from the battery at each time period. Values are always positive or zero.

Example: A value of 2.0 kW means the battery is discharging at 2.0 kW at this time period.

Power Active¶

The net active power (discharge - charge) at each time period. Positive values indicate net discharge, negative values indicate net charge.

Example: A value of -1.5 kW means the battery is charging at 1.5 kW net (discharge is less than charge).

Energy Stored¶

The current energy stored in the battery at each time boundary. Values range from 0 to the configured capacity.

Example: A value of 7.5 kWh means the battery currently stores 7.5 kWh of energy.

Power Balance¶

The marginal value of power at the battery terminals. See the Shadow Prices modeling guide for general shadow price concepts.

This shadow price shows how much the total system cost would change if you could inject or extract 1 kW of power at the battery terminals.

Interpretation:

• Positive value: Power at the battery is valuable (system would benefit from more charging capacity)
• Negative value: Power at the battery is costly (system would benefit from more discharging capacity)
• Zero value: Battery power balance is not constraining the optimization

Example: A value of 0.15 means that if the battery could accept 1 kW more power, the total system cost would decrease by $0.15 at this time period.

Energy In Flow¶

The marginal value of relaxing the charging constraint. See the Shadow Prices modeling guide for general shadow price concepts.

This shadow price shows how much the total system cost would change if the battery could charge more energy.

Interpretation:

• Zero value: Charging constraint is not limiting
• Nonzero value: Battery charging is constrained and relaxing the constraint would reduce costs

Example: A value of 0.05 means that if the battery could charge 1 kWh more, the total system cost would decrease by $0.05 at this time period.

Energy Out Flow¶

The marginal value of relaxing the discharging constraint. See the Shadow Prices modeling guide for general shadow price concepts.

This shadow price shows how much the total system cost would change if the battery could discharge more energy.

Interpretation:

• Zero value: Discharging constraint is not limiting
• Nonzero value: Battery discharging is constrained and relaxing the constraint would reduce costs

Example: A value of 0.08 means that if the battery could discharge 1 kWh more, the total system cost would decrease by $0.08 at this time period.

SOC Max¶

The marginal value of additional storage capacity. See the Shadow Prices modeling guide for general shadow price concepts.

This shadow price shows how much the total system cost would decrease if the battery had 1 kWh more capacity.

Interpretation:

• Zero value: Battery is not at maximum capacity
• Negative value: Battery is full and more capacity would reduce costs
• Positive value: Battery capacity constraint is not binding

Example: A value of -0.12 means that if the battery had 1 kWh more capacity, the total system cost would decrease by $0.12 at this time period.

SOC Min¶

The marginal value of deeper discharge capability. See the Shadow Prices modeling guide for general shadow price concepts.

This shadow price shows how much the total system cost would decrease if the battery could discharge 1 kWh deeper (below current minimum).

Interpretation:

• Zero value: Battery is not at minimum capacity
• Positive value: Battery is empty and the ability to extract more energy would reduce costs
• Negative value: Battery minimum capacity constraint is not binding

Example: A value of 0.10 means that if the battery could discharge 1 kWh deeper, the total system cost would decrease by $0.10 at this time period.

All sensors include a forecast attribute containing future optimized values for upcoming periods.

Troubleshooting¶

Battery Section Not Visible¶

Problem: The Battery Section element type does not appear in the element selection list.

Solution: Enable Advanced Mode in your hub configuration. Battery Section is only available when Advanced Mode is enabled.

No Power Flow¶

Problem: Battery Section shows zero power even when connected.

Solution: Verify that Connection elements are properly configured to connect the Battery Section to other elements (nodes, grids, etc.). Battery Section does not create implicit connections like the standard Battery element.

Connection Errors¶

Problem: Cannot create connections to or from the Battery Section.

Solution: Ensure the Battery Section name matches exactly in both the Connection source and target fields. Check that the Battery Section element exists before creating connections.

Next Steps¶