Eg4 18kPV AC Coupled Solar Array Frequency Shifting still not working 1 year in

[ElectroStaticD]

I purchased an 18kPV and 6 LiPo4 100Ah 48v batteries from Signature Solar about a year ago. I can't seem to find anyone at signiture solar or EG4 who knows how to configure the Frequency shifting to match my Enphase inverter's settings and work properly. I've spent hours on the phone with both companies. Please help me.

My setup is 59 Enphase IQ7+ inverters connected to the Gen port of the 18kPV. in AC Couple mode The 18kPV's load is connected to my main 200A panel. I'm on the latest firmware (FAAB-1A1A) and whenever my system goes off grid, if my solar panels start outputting more than ~16,000 w, the 18kPv just powers off the load port completely after a minute or so and the whole house goes off. I suspect the frequency shifting is not working properly as it works great when the solar is producing less than ~16,000 W. How do I go about configuring the settings (in the UL Compliance tab?) on the EG4 inverter's installer settings to properly do frequency shifting matching my enphase setup? My Enphase grid profile report is attached (IEEE 1547-2015 FW200pct/Hz) as well as the current EG4 inverter settings. I can change to a different grid profile if needed.



Current settings on the EG4 Inverter

 

[robby]

The only thing I can tell you is that some settings on that inverter can only be done by SS/EG4 and not by the end user.

 

[ElectroStaticD]

The only thing I can tell you is that some settings on that inverter can only be done by SS/EG4 and not by the end user.

I have installer access which, I believe, is what signature solar has.

 

[zanydroid]

if my solar panels start outputting more than ~16,000 w

Isn’t this way off 1:1 ratio that is generally recommended for AC coupling unless there is direct communications between battery and inverter (ie within Enphase ecosystem)? Does the EG4 manual explicitly allow this >1.33x ratio?

18kpv has a 12kW inverter/charger

 

[ElectroStaticD]

Isn’t this way off 1:1 ratio that is generally recommended for AC coupling unless there is direct communications between battery and inverter (ie within Enphase ecosystem)? Does the EG4 manual explicitly allow this >1.33x ratio?

18kpv has a 12kW inverter/charger

Yeah it’s way off but I’m not using enphase batteries so it doesn’t matter. They just do that to sell you more battery and because of the way their batteries are designed to use micro inverters.

And the way the AC couple works is when on grid it’s just bridged to the load/grid so it operates normally

 

[zanydroid]

Yeah it’s way off but I’m not using enphase batteries so it doesn’t matter. They just do that to sell you more battery and because of the way their batteries are designed to use micro inverters.

You have it backwards.

Enphase batteries IIUC do NOT have a ratio (or a much more generous one) because they use PLC to communicate. IOW if you don’t buy their batteries, then you have tighter design constraints based on industry wide orthodoxy (which is a consequence of the lowest denominator 1741SA GTI behavior)

Almost all AC coupling vendors (SMA, Victron, etc) have the 1:1 rule

And the way the AC couple works is when on grid it’s just bridged to the load/grid so it operates normally

Sure but that’s a different situation. There is no notion of overload to protect against since it just goes to the grid.

When off grid the grid forming inverter needs to protect against the GTIs continuing to seek to push 16kW. With generic 1741SA frequency shift, the response time mandated by standard is IIRC a few seconds, which is not good enough. With PLC comms within Enphase, and with intentional engineering, they can achieve lower than this, and also customize the ramp curve etc.

16kW is clearly at least 4 Enphase branches so you can consider moving one branch to combine upstream of your 18kpv (so it is grid tie only) and downstream of your CTs (so it can do self consuming).

I’m not advocating for Enphase merely trying to explain. I don’t own Enphase and tend to suggest people consider other micro vendors

 

[zanydroid]

Search for Factor 1.0. I am traveling so I have to dip out of this thread and can’t explain beyond what I remember off hand of theory, hopefully others can help you more

 

[ElectroStaticD]

You have it backwards.

Enphase batteries IIUC do NOT have a ratio (or a much more generous one) because they use PLC to communicate. IOW if you don’t buy their batteries, then you have tighter design constraints based on industry wide orthodoxy (which is a consequence of the lowest denominator 1741SA GTI behavior)

Almost all AC coupling vendors (SMA, Victron, etc) have the 1:1 rule


Sure but that’s a different situation. There is no notion of overload to protect against since it just goes to the grid.

When off grid the grid forming inverter needs to protect against the GTIs continuing to seek to push 16kW. With generic 1741SA frequency shift, the response time mandated by standard is IIRC a few seconds, which is not good enough. With PLC comms within Enphase, and with intentional engineering, they can achieve lower than this, and also customize the ramp curve etc.

16kW is clearly at least 4 Enphase branches so you can consider moving one branch to combine upstream of your 18kpv (so it is grid tie only) and downstream of your CTs (so it can do self consuming).

I’m not advocating for Enphase merely trying to explain. I don’t own Enphase and tend to suggest people consider other micro vendors

That's a good idea to move one branch. I have 4 now but this is a hassle.. but I think the inverter should be able to handle up to 18,000 w for short periods of time. I don't think the frequency shifting is happening at all. At least I can't see it happening when looking at the gen port's frequency graph.

 

[zanydroid]

What is your SoC?

Whether it handles 18kW… It depends on BMS, how conservative it is, etc. What is your basis for believing this, surge capacity on output? That uses shared components but is not identical. Discharge BMS limit could be different from charge. Though with your batteries it should be fine

I believe some (most?) implementations use F-W strictly to cut off charging gracefully rather than for continuous power management.

 

[ElectroStaticD]

What is your SoC?

Whether it handles 18kW… It depends on BMS, how conservative it is, etc. What is your basis for believing this, surge capacity on output? That uses shared components but is not identical. Discharge BMS limit could be different from charge. Though with your batteries it should be fine

I believe some (most?) implementations use F-W strictly to cut off charging gracefully rather than for continuous power management.

Last time this happened the SOC was 90%. I can discharge to 50% and see if that helps. I have my max charge\discharge current set to 500A DC each.

 

[zanydroid]

Last time this happened the SOC was 90%. I can discharge to 50% and see if that helps. I have my max charge\discharge current set to 500A DC each.

Then that could also be a SoC cutoff. I don’t know if EG4 has it adjustable. For a smaller battery setup than yours 90% would be a good default cutoff.

IMO one of the things you give up with AC coupling compared to DC coupling is “perfectly optimal” behavior