How to divert PV to grid and not charge battery

[rob0101]

Is there a setting to prevent the battery charging from PV? I'd like to automate spilling excess morning solar with a positive price to the grid.

I thought number.sigen_plant_ess_max_charging_limit might do it if set to zero, but alas, no.

The Sig app has a "hold battery" option which achieves no charging, but also stops discharging.

[TypQxQ]

Try setting it to 0.01 instead of 0.
0 is often interpreted as a default or not set.

[TypQxQ]

Have you enabled "Remote EMS (Controled by Home Assistant)" and what mode is your plant running in?

[rob0101]

I'm wondering if sigen_plant_charge_cut_off_soc was a configurable number rather than sensor, setting that to the current SOC would prevent further charging and force all spare PV to export.

I think I saw you're adding that option.

[rob0101]

Have you enabled "Remote EMS (Controled by Home Assistant)" and what mode is your plant running in?

Yes. Max self consumption.

[TypQxQ]

Not sure why it doen't work but...
If you'd try Discharge PV first and instead limit the discharge of battery?

[rob0101]

I don't want to limit discharge since the battery needs to be available if solar dips below the house load. Otherwise it starts importing from the grid.

[Adze1502]

As per Sigen modbus documentation https://github.com/user-attachments/files/21053404/Modbus.Protocol.EN.-.SIGEN.pdf the number.sigen_plant_ess_max_charging_limit and number.sigen_plant_ess_max_discharging_limit settings only work in EMS mode charging or discharging. Setting these values while in mode max self-consumtion does nothing.

To awnser your question on howto divert PV to grid and not charge battery, there are two options i know that do work.

Option 1: Set EMS mode to 0x05 (Command discharging) and periodicly (every 2 seconds or so) set value number.sigen_plant_ess_max_discharging_limit equal to sensor.sigen_plant_consumed_power value.

Option 2: Set EMS mode to 0x03 (Command charging) and set value number.sigen_plant_ess_max_charging_limit to 0,01. Activate peak-shaving in the app and set max grid peak-power to 0.0kW. This way the battery will still discharge to prevent peak usage over 0kW. But be sure to put the peak-shave soc lower than the current active soc, otherwise the battery will start charging with surplus PV.

Both options are stil not ideal. Would be nice if number.sigen_plant_ess_max_charging_limit and number.sigen_plant_ess_max_discharging_limit settings were respected in max self-consumtion mode.

[rob0101]

I think setting the max charging SOC to the current SOC works. I only get brief periods to test it so need more time to test each scenario.

[Adze1502]

Also a good option! Never thought of this.

[AndyFlysJabs]

the problem with using SOC is that it results in battery charging at full PV availability(or some other system lower level that I havent yet seen) or zero.

If your export limited to say 5kw, and the solar is capable of producing 12kw then if soc is set so that the battery doesn't further charge then in this case the remaining potential 7kw of solar that could be used to charge is simply withheld. youll get your 5kw of export but indoing so forego 7kw of battery recharge. you either get 5kw of export or 12kw of charge

BTW this is how I do it

[rob0101]

I see the issue. The real solution is for Sig to provide modes for spare solar destination.. Export first or battery first.

[mattblack59bus]

I currently do this by setting the battery charge limit to 0.1kw in the Sigen App (Remote EMS mode > Settings > Battery Power Limit), once the solar reaches 100w it will then feed into the grid, once the feed in tariff price goes negative my HA sets the grid export limitation to zero and effectively load follows whatever we use in the house. I then have to manually set the charge limit (battery power limit) back to maximum or 12kw in my case, not ideal but looking for a better way.

[rob0101]

Is there a setting to prevent the battery charging from PV? I'd like to automate spilling excess morning solar with a positive price to the grid.

I thought number.sigen_plant_ess_max_charging_limit might do it if set to zero, but alas, no.

The Sig app has a "hold battery" option which achieves no charging, but also stops discharging.

The latest firmware pushed to my 3phase inverter last week now allows the charging power limit to be set when in Max Self-Consumption mode.

Sigenergy told me a month ago this would be possible with the next modbus spec update, so I guess there's a new modbus spec being used today by some inverters.

[TypQxQ]

Try setting it to 0.01 instead of zero. Might work but only if you're in HA control mode.

Haven't heard anything about a new release but they don't send me anything. Got the last documentation from a user here as they don't even respond to my emails.

[Michirieger]

Actualy i think i got that update last weekend and thince then everything is completely broken.

if i set the charging limit to 4kW and solar dips below that the system starts importing power from grid to charge the battery which i definitely want to avoid.

[TD944]

You can keep it in maximum self consumption and set the max charging limit below the current state of charge (or 0). Then the battery won't charge but will allow discharging if required.