Freeze exporting clarification

[mikewhitby]

Can someone help me understand freeze export? The docs state:

The battery is in demand mode, but with charging disabled. The battery or solar covers the house load. As charging is disabled, if there is excess solar generated, the current SoC level will be held and the excess solar will be exported. If there is a shortfall of generated solar power to meet the house load, the battery will discharge to meet the extra load.

However I currently see this in my plan textual description:

The battery is currently at 76% and is freeze exporting to 99.0% for the next 1 and a quarter hours.

How can it charge to 99% if charging is disabled?

I did see a post here about this which stated:

The first is I suggest operating per the documentation but the freeze discharge description is however missing the words "to the target (limit) SoC level"
Battery is in discharge mode
Charging above the target level is disabled
Excess solar above the target level will be exported

I have a sigenergy system though which is controlled by an automation, that sets the following:

        # Freeze Discharging
        # Docs:
        #  Freeze exporting (mapped to Freeze Discharging in sigenergy_sigenstor.yaml) - The battery is in demand mode,
        #  but with charging disabled. The battery or solar covers the house load. As charging is disabled, if there is
        #  excess solar generated, the current SoC level will be held and the excess solar will be exported. If there is
        #  a shortfall of generated solar power to meet the house load, the battery will discharge to meet the extra load.
        # In Sigenergy, this is effectively "self consumption" mode with charging prohibited
        - conditions:
            - condition: state
              entity_id: input_select.predbat_requested_mode
              state: "Freeze Discharging"
          sequence:
            - service: number.set_value
              data_template:
                entity_id: number.sigen_plant_ess_charge_cut_off_state_of_charge
                value: 0
            - service: number.set_value
              data_template:
                entity_id: number.sigen_plant_ess_discharge_cut_off_state_of_charge
                value: 0
            - service: number.set_value
              data_template:
                entity_id: number.sigen_plant_grid_import_limitation
                value: 0

As you can see, the charge and discharge cut off state of charge is 0, presumably so the battery can discharge but not charge.

• This seems to meet the description in the docs, but not the description in the linked issue
• My plan textual description would seem to be implying it is doing something the docs say it cannot do (charging to 99%)

Which one is right? :)

[gcoan]

Can someone help me understand freeze export? The docs state:

The definitive explanation of how Predbat plans and expects for each battery state to work is as per the documentation https://springfall2008.github.io/batpred/what-does-predbat-do/#predbat-modes

The battery is currently at 76% and is freeze exporting to 99.0% for the next 1 and a quarter hours.

How can it charge to 99% if charging is disabled?

I am pretty sure that this is a minor bug and the SoC limit of 99% is what is used internally within Predbat code to represent the freeze export and on the predbat plan this dummy 99% is now supressed but it looks like the text description of the plan missed this suppression out.

If I do a freeze export now, my plan doesn't show 99%:

I did see a post here about this which stated:

I have a sigenergy system though which is controlled by an automation, that sets the following:
...`

As you can see, the charge and discharge cut off state of charge is 0, presumably so the battery can discharge but not charge.

• This seems to meet the description in the docs, but not the description in the linked issue
• My plan textual description would seem to be implying it is doing something the docs say it cannot do (charging to 99%)

Which one is right? :)

The documentation is right. That issue was 18 months ago and a lot has happened since then to Predbat, including adding support for SigEnergy inverters!
It is worth being aware that the documentation description of modes is definitive for what predbat expects but not all inverters can fully deliver precisely what predbat expects it to do. This is down to inverter limitations as Predbat has to cater for lots of inverter types and some behave differently.

I'll look at the text plan issue separately

[gcoan]

Bit more digging in the code, in the HTML plan output, as I remembered:

                if limit == 99:  # freeze exporting
                    if not had_state:
                        state = ""
                    if state:
                        state += "</td><td bgcolor=#AAAAAA " + cell_style + ">"  # charging and freeze exporting in same slot, split the state into two
                        split = True
                    else:
                        state_color = "#AAAAAA"
                    state += "FrzExp&rarr;"
                    raw_state = "FrzExp"
                    show_limit = ""  # suppress displaying the limit (of 99) when freeze exporting as its a meaningless number

but in the code that builds the short text description, the limit is included for freeze exporting when it shouldn't be:

            if self.export_limits_best[export_window_n] == 99:
                text = "freeze exporting to {}% for the next {}".format(target_export, self.duration_string(self.export_window_best[export_window_n]["end"] - minutes_now))
            else:
                text = "force exporting to {}% for the next {}".format(target_export, self.duration_string(self.export_window_best[export_window_n]["end"] - minutes_now))

I will issue a code fix to remove the limit % for freeze exporting

[daviessm]

Completely unrelated but @gcoan your HTML plan screenshots look way better than everyone else's, is that something you've worked on locally and are going to upstream (he says hopefully)?

[gcoan]

Completely unrelated but @gcoan your HTML plan screenshots look way better than everyone else's, is that something you've worked on locally and are going to upstream (he says hopefully)?

I use the Predbat table card to reformat my plan as I want it to look.

Its linked in the predbat documentation https://springfall2008.github.io/batpred/predbat-plan-card/#customising-and-reformatting-the-predbat-plan

going briefly back to your original issue

in the code that builds the short text description, the limit is included for freeze exporting when it shouldn't be

I have fixed this and it was incorporated in predbat release 8.34.5. Thanks for spotting it.