18KPV AC Couple mode stopped working after adding GridBoss - Inverters https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/ EG4 Community Forum Discussion Board en-US Sun, 12 Jul 2026 08:44:07 +0000 wpForo 60 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-19377 Thu, 09 Oct 2025 21:16:55 +0000 We apologize that we were unable to make changes to the firmware at this time. Updating the firmware involves a formal process, which requires careful review, decision-making, and approval before any changes can be implemented.

Also, the GridBoss manual does mention that all Smart Load, AC couple, and generator functionality will be connected to and configured on the GridBoss.



1827]]> Inverters EG4 Eric https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-19377 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-19372 Thu, 09 Oct 2025 05:46:54 +0000 So I see that there was an firmware update for the FlexBoss/18KPV/12KPV, which bumped it from EG4_FAAB-2122 to EG4_FAAB-2525. I installed this hoping for AC couple mode on the 18KPV would work again as it did prior to my GridBoss install, even though there was nothing in the change log that would indicate this change. After installing FAAB-2525 I went back and re-initialized AC couple mode in my 18KPV. I then found out that AC couple mode still did not work. As a final try, I then updated my GridBoss from EG4_IAAB-13 to EG4_IAAB-1600. Checked AC couple mode again. Still no luck.

Eric, What happened to passing this request to your support team? Are there to be any actions expected from them in the future?

Again, it seams that the hardware still has the capability of excepting an AC inverter connection to the 18KPV's generator input, but selecting AC couple mode in the 18KPV it has no effect even though the radio button says that it's enabled. Again this used to work before I installed the GridBoss. I have lost the ability to make use of the power from my AC coupled micro inverters because the 18KPV's generator port does not support AC couple mode when a GridBoss is installed. I also can't just move the AC coupled micro inverters connection from the 18KPV to the GridBoss because of distance and other. Note that nowhere in the 18KPV or GridBoss documentation states that the AC couple function/mode will not work anymore when the two are used.

Totally disappointed. 

]]> Inverters fkitzmann https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-19372 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-19197 Tue, 16 Sep 2025 00:43:09 +0000 Correction.. Not demand response mode.. Voltage Reactive Power Mode

 

Primary Control: Register 59 (ReactivePowerCMDType)

Register 59 controls the type of reactive power control mode:
  • Range: 0-7
  • Description: Reactive command type with detailed options:
  • 0: Unit power factor (disabled/off)
  • 1: Fixed PF
  • 2: Default PF curve (American machine: Q(P))
  • 3: Custom PF curve
  • 4: Capacitive reactive power percentage
  • 5: Inductive reactive power percentage
  • 6: QV curve (Voltage-Reactive Power Mode) ✅
  • 7: QV_Dynamic
]]> Inverters ElectroStaticD https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-19197 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-19196 Mon, 15 Sep 2025 22:26:16 +0000 Initially I had AC coupling mode enabled on my 18KPV to couple my existing AC inverters to it's Generator port input. This had been working until I added a GridBoss to manage my AC power distribution. Prior to the GridBoss addition, I had been able to monitor power using the monitoring connection through the monitoring app. Now with the GridBoss added, I'm not able to push AC inverter power back to either the grid or locally. I have tried all combinations of enabling AC coupling mode on both the 18KPV and the GridBoss. When I look at the physical generator connection at either the 18KPV or the GridBoss, there is no AC reference voltage at the generator terminals. I would like to have the 18KPV generator port support AC coupling mode since that's where my AC solar is connected to and it would be difficult to move this connection over to the GridBoss. In any case, I have also reviewed the following document (AC Coupling Guide for EG4 18kPV and 12kPV Hybrid Inverters) to make sure everything is configured properly. Both the 18KPV and GridBoss have the most current firmware - 18KPV - FAAB-2021, - 18/1/1,  GridBoss - IAAB-1300. Again, this was working prior to GridBoss install.

Below shows AC coupling power prior to GridBoss install.

-- attachment is not available --

Below shows AC coupling power after to GridBoss install.

-- attachment is not available --

 

I don't know about the grid boss but the frequency shifting settings for the 18kpv are available on the Maintenance > UL Compliance tab on the monitoring website (tab only shows up if you are an installer).  I have found that if (hold register 21 bit 2) is not enabled, the frequency shifting does not operate.  Additionally, the settings for setting the droop on that page are incorrect.  The value is read and written to the 18kpv incorrectly.  You have to use rs485 to properly set it.  Below is a summary of which registers to set.  

 

 

Over Frequency Droop Settings:

  • Register 115 (OVFDerateStart): Over Frequency Derate Start Point
  • Unit: 0.01Hz (so 6000 = 60.00 Hz)
  • Description: Starting frequency point for over-frequency derating power
  • Register 124 (OVFDerateEnd): Over Frequency Derate End Point
  • Unit: 0.01Hz (so 6000 = 60.00 Hz)
  • Description: End frequency point for over-frequency load reduction
  • Register 136 (OVFDeratePctPerHz): Over Frequency Derate Rate
  • Unit: %/Hz
  • Range: 1-100
  • Description: Power reduction rate per Hz above the start frequency

Under Frequency Droop Settings:

  • Register 134 (UnderFrDroopStart): Under Frequency Droop Start Point
  • Unit: 0.01Hz (so 4500 = 45.00 Hz)
  • Description: Starting frequency point for under-frequency load reduction
  • Register 135 (UnderFrDroopEnd): Under Frequency Droop End Point
  • Unit: 0.01Hz (so 4500 = 45.00 Hz)
  • Description: End frequency point for under-frequency derating
  • Register 193 (UnderFrIncreasePctPerHz): Under Frequency Increase Rate
  • Unit: %/Hz
  • Range: 1-100
  • Description: Power increase rate per Hz below the start frequency

Open Loop Response Time:

  • Register 97 (DelayTimeForOverFDerate): Frequency Response Delay Time
  • Unit: Main period (milliseconds)
  • Range: 0-1000
  • Description: Delay time before frequency derating takes effect

Enable/Disable Control

Over Frequency Load Derate Enable/Disable:
  • Register: Hold Register 21 (Function Enable Register)
  • Bit: Bit 1 (OVFLoadDerateEnable)
  • Control: 0 = Disabled, 1 = Enabled

 

]]> Inverters ElectroStaticD https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-19196 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-17957 Thu, 14 Aug 2025 20:09:12 +0000 Just checking again - Any updates from the team on getting AC couple mode working again on 18kPV when a GridBoss exists?

]]> Inverters fkitzmann https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-17957 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-16614 Thu, 19 Jun 2025 17:29:52 +0000 I don’t have any updates at this time. Currently, the only way to use AC Coupling is through the Gridboss. If there are any changes or updates in the future, we’ll be sure to share them.

]]> Inverters EG4 Eric https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/paged/2/#post-16614 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-16588 Tue, 17 Jun 2025 16:37:04 +0000 Any updates from the team on getting AC couple mode working again on 18kPV when a GridBoss exists?

Again, In my case, I'm not trying to use the AC couple mode at the GridBoss generator port. I'm trying to use AC couple mode at the 18kPV's generator port. Maybe you can change the software to have a selection of using 18kPV or GridBoss but not both if that is what is required to support the hardware.

]]> Inverters fkitzmann https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-16588 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-15897 Sat, 12 Apr 2025 17:02:24 +0000 I only need to continue with my one current connection to the generator port on the 18KPV, which worked prior to adding the GridBoss.

]]> Inverters fkitzmann https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-15897 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-15887 Fri, 11 Apr 2025 19:40:30 +0000 Inverters EG4 Eric https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-15887 RE: 18KPV AC Couple mode stopped working after adding GridBoss https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-15871 Thu, 10 Apr 2025 20:43:41 +0000 Eric, Yes - I know of the connection at the GridBoss. Just a lot more work to move my AC solar connections back to the GridBoss. Seems that since the hardware originally supported this path in the 18KPV and that path still physically exists and everything back at the inverter is still the same, i.e. circuit breaker, relay and current monitor. It appears to just be a software & update issue. Is there any possibility to get the software changed to support either the GridBoss AC Coupling or 18KPV AC Coupling (selection) or possibly both. Obviously you don't want two generators connected, but you could have up to 2 AC Coupled solar connections through these paths. It gives the installer more options. How is the AC Coupled connection handled when you have two or more 18KPV's? Can you use both of them at the same time (AC solar only)?

]]> Inverters fkitzmann https://forum.eg4electronics.com/community/inverters/18kpv-ac-couple-mode-stopped-working-after-adding-gridboss/#post-15871