Sigen EMS Remote Control – Export Solar to Grid First Without Discharging Battery #300
Replies: 6 comments 4 replies
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In my Sigen installation, it is the default behaviour (without anything in HA)...
That is what you try to do, or did I miss the point completely? |
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Hi Mate, Yes, I understand that’s the normal behaviour and it does work as designed, but it’s not quite what I’m trying to achieve. I’m specifically looking to avoid charging the battery first. My preference is that any solar being generated is exported to the grid first, and only the remaining excess should go toward charging the battery. I’m on a single-phase connection with a 5 kW export limit to the grid, and even with that limit my battery still ends up fully charged by around midday anyway. My goal is really just to prioritise home solar → grid, and then battery last, rather than the battery first. |
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@blackcomb123 this is something that has been flagged with SigEnergy (via Australia) that they need another Mode added to support this situation. Scenario put to them was that in the early AM (for lots of days) is the only time that you might get any +ve FIT, before it then goes -ve FIT for the rest of the day. So being able to export early on, then switch to charging up the ESS (vs the other/current way, where your ESS if full early, but you've missed out on exporting for $, then spend the day curtailed for export) is needed. Trying to remember the specifics from testing, but iirc it came down to setting the system to Self-Consumption or even Force-Export ended up with the ESS being the priority or what littke energy you have left in the ESS being discharged to export to the grid. Also the ability to turn on/off the setting to achieve the desired outcome is not supported (as the only modbus register for the entities concerned are 30,xxx registers that are Read Only, whilst 40,xxx Read/Write registers are want it needed to allow controlling them). I have to chase the assigned contact in Sig AU to see how far they've got with managing to get Sig R&D to add the "Mode 7" option for EMS Work Mode. |
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ah alright, the export limit was something I missed. I do not have that, so I did not understand how there can be solar excess when exporting to grid |
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@Roving-Ronin thank you for following this up with SigEnergy. |
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I achieve exactly this by using the "Sigen Plant ESS Charge Cut-Off State of Charge" (see screen capture for exact Node Red implementation) With this I set this to 30% firs thing in the morning and if my battery is less than 30% then itll charge up to 30% and then stop, charging and export. For me most mornings my Battery is > 30% SOC and as such it does what I want. You could set it to 0% to absolutely force export but to me Im happy for the battery to get some recovery if needed so I can cope with a blackout should one occur.... 
Im happy to share my whole Node red export settup if its of use.... im my case I use Local Volts as the retailer and as such the set up will depend on if you have them or some other retailer etc... Andy |
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In fact here it is, help yourselves, this entity, sensor.earnings_flex_up, earnings export flex up in Australia speak is the current grid spot price i will be paid for export in that 5minute window:- File Updated 14-02-26 to fix some errors where a flow variable is tested for boolean state true or false and was ignoring initialization where it has neither state until one is first set. |
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Ive got a few extras added to NodeRed, if it doesnt work let me know what is the issue and Ill track down what I added that you will also need |
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Actually in looking at the code there are some HA helpers I created that I need to explain:-
This is what it looks like in my Energy Management Dashboard:- This set up is reasonably conservative, I take teh approach that as my battery SOC decreases then in steps I decrease my export and stop everything when i get to 30%. SOme people who are more aggressive in chasing export dollars might adopt the approach that Ill export full speed until the battery stops exporting and at a point later I will charge from grid when rates decrease to allow.... I think this approach could earn more money, but there is risk that what ever caused the blip in prices could extend beyond a short timeframe and then youd be buying back what you previously sold and making a loss while doing it... I have a hybrid BYD shark 6 that has a 29kw EV battery that I could use to supplement my home battery via teh Sigenergy DC charger , and that could run on petrol to recharge should I want it to...so far its a level of complexity Im not prepared to investigate. I have all the hardware in place and Ive seen posts from folk who say it does work... and if it becomes needed due cyclone or some other weather event then I can see how I feel at the time in terms of benefit vs loss of car warranty etc... |
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I found an issue with my code where the original poster wanted to export in the morning before battery charging occurs. The approach I took in my code does that, but at the expense of allowing no battery charge to occur at all while export is occurring. Initially in the morning when the PV system is producing weakly and has less potential output than any export limits then its fine. Once the PV output reaches the grid export limit then the system will only export the limit and any additional potential power is ignored and doesn't charge the battery. That is because the mode I use has battery charging higher in priority than export and i use other controls to curtail that. I think there is a better approach where you can export and charge the battery. I haven't written any code yet but my approach I think will be that for a 20 second period I will go to mode maximum self consumption, and look at battery charge power and measure it. if its (charge power measured) less than export limit then set the EMS mode to "Command charging (consume PV power first)" (mode 4) and then set "sigen_plant_ess_max_charging_limit" to zero (which stops the battery charging at all and (noting that sigen_plant_ess_max_charging_limit only has effect in EMS modes 3 or 4) . I also noted that its a write only control and doesn't on read reflect what you previously set it to...... if its (charge power measured) more than the export limit then set the EMS mode to "Command charging (consume PV power first)" (mode 4) and then set sigen_plant_ess_max_charging_limit to the measured power minus the export power limit amount and that should result in export of the limit and battery charging of the rest. (understanding that in the system I think Battery charging is prioritised over export so any variations will reflect in export not battery power) Now the issue is that PV is dynamic and as clouds and sun intensity changes the power available values will constantly change. if PV potential power decreases (clouds etc) then under this your export would shrink by whatever the variance is. As such you are leaving money on the table so to speak if you want export to be max at all possible times. If the PV intensity increases, then nothing will happen because your system export limit kicks in and the Battery charge level has a maximum value set so the potential remains as potential only. In other words you might have actually been able to increase your battery charge rate, but the testing process results in zero exports while you measure the available power In Australia our grid pricing is set at 5 minute intervals, I'm thinking that I repeat the whole process every 5 minutes aligned to the grid value change This should mean that I export the maximum the system is capable of whenever I have the battery charge current set to zero, and roughly the maximum minus whatever variations are occurring at any point in time whenever the battery charge current is set above zero. Issues I have seen, in playing with the controls manually to get a feel if this will work I noted that the maximum battery charge current you can set is defined by how many and what type of battery modules you have, If you try and set it higher than the 1/2C value (plus a bit...) in my case for a 24kw battery it was 12.6kw then a node red error message is created. I don't know what effect that will have so I think you need to understand what your maximum battery charge current can be and ensure you never try to set it higher than that. In my case I have 19kw of PV so can actually potentially charge at a higher rate than allowed. Has anyone else gone down this path? Andy |
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Hi everyone,
I’m currently working on automating Remote EMS Control for my Sigen inverter through Home Assistant. My existing configuration is working correctly from a control perspective, but I’m trying to fine-tune the energy behaviour and would appreciate some guidance from anyone who has achieved a similar setup.
Goal
During the daytime, I want the system to:
1. Export as much solar generation to the grid as possible
2. Only charge the battery with excess solar
3. Prevent the battery from discharging to the grid
Current Setup
• 16 kW solar array
• 40 KW Sigen Battery reaches 100% by around 12 PM even when exporting aggressively.
• I have created a Custom Plan that preserves battery charge so it does not discharge to the grid.
• I only want battery charging to occur from solar surplus, not from the grid, and not battery discharge for export.
Issue
I tested Remote EMS → Command Discharging (PV First) expecting it to prioritise solar export only. However, I noticed that when solar production is insufficient to meet the configured export limit, the inverter starts discharging the battery to maintain export, which is not what I want.
What I’m Trying to Achieve
• Priority Order:
Solar → Grid Export → Battery Charging
• Never: Battery → Grid Export
• Battery should only:
• Charge from excess solar
• Discharge for home consumption if needed (optional/flexible)
• Not discharge just to meet export limits
Questions
1. Has anyone successfully configured Sigen EMS to export only from solar and block battery discharge to the grid?
2. Is there a Remote EMS command or parameter that strictly enforces PV-only export?
3. Is it possible to switch to a Custom Plan via Home Assistant automation or API instead of manually selecting it in the app?
Any insights, configuration examples, or API references would be greatly appreciated. Thanks in advance!
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