Troubleshooting DEYE Hybrid inverter with AC-coupled microinverters (GEN input) and DC-connected PV modules

[panel guy]

Hi everyone,

I recently installed a Deye Hybrid inverter (8k SG01-LP1-EU) with two DC strings of panels (3600W each, totaling 7200W), along with a DIY 15kWh LFP battery pack managed by a JK Inverter BMS communicating via CAN to the Deye inverter, providing real-time battery data. I am planning to add microinverters connected to the inverter's GEN port, so I decided to perform some tests first.

For testing purposes, I got an Enphase IQ7+ microinverter connected to a 400W solar panel. On-grid, everything works perfectly, and the microinverter connected to the GEN port produces normally.

However, issues arise when switching to off-grid mode: irrespective of the battery SOC (tested at around 50%), the Deye inverter performs frequency shifting as soon as my DC panels produce around 2000W, causing the microinverter connected to the GEN port to shut down.

Settings I've already adjusted:

• GEN Port Use:
  
  • Micro Inv Input: Enabled
  • ON: 85%
  • OFF: 90%
  • AC Couple Frequency: 51.5 Hz
• Set maximum battery charging current to 120A in both Deye inverter and JK BMS settings, ensuring no artificial limitation on the microinverter production.

Observations:

• If I switch off both DC strings, the frequency shifts back down, and the microinverter resumes production.
• If I disconnect one DC string, reducing the total DC power below approximately 2000W, the microinverter also resumes production.
• If I introduce a heavy load (such as EV charging), the microinverter resumes production even if the DC panel production is above 2000W.

I'm puzzled by this behavior, especially the apparent 2000W threshold that triggers frequency shifting. I've carefully reviewed inverter settings but found nothing corresponding to this power limit.

Does anyone have any idea what could be causing this or experienced similar behavior?

Thanks a lot for your precious help!

 

[Dave-OLW]

I am Trying to connect a Sunsynk 3.6kw inverter to the auxiliary input of the Sunsynk 8kw.
With nothing connected to the port at the moment, when battery reaches setting 'AC couple OFF Bat ' it sets the frequency high 52 Hz this affects all household appliances clocks etc.
I changed the frequency setting on the auxiliary input menu to 50 but it still sets the frequency to 50.5.
I believe Deye and Sunsynk are the same.

david

 

[houseofancients]

I am Trying to connect a Sunsynk 3.6kw inverter to the auxiliary input of the Sunsynk 8kw.
With nothing connected to the port at the moment, when battery reaches setting 'AC couple OFF Bat ' it sets the frequency high 52 Hz this affects all household appliances clocks etc.
I changed the frequency setting on the auxiliary input menu to 50 but it still sets the frequency to 50.5.

frequency shift cannot happen if your 8kw sunsynk is grid connected, as the bus syncs to the grid frequency

I believe Deye and Sunsynk are the same.

they are

david