EG4 18kPV Grid Tied TriLug Meter - CT Placement

[DaveNSueM]

Pulled trigger on EG4 18kPV - will be grid tied (already have interconnect agreement/net meter/local permits), NO backup load (have generator) and NO battery to start (future add)...pretty basic setup to start - a few pics/diagrams are attached. Service is 320a dual lug meter feeding house 200a load panel approx 150' underground and 100a pool/pavilion panel next to meter.

I was planning on supply side connection in 100a pool panel (via taps); however, utility has now said OK to adding 3rd lug in meter box and AHJ is happy with that too. Seems like a simple, clean connection method overall but would like opinions on this and a few other questions:

• Is the 3rd lug connection described above the best way to go with my setup design? Any downsides...other approaches to consider?
• In the described setup, where would I place the CT's...the 3rd lug PV grid line (which I am guessing would only sense PV production and see it as all going to grid) or the pool panel load lines even though that is minimal load?
  • The house panel is where main loads are located; however, I do not have close access to those feeders - have been exploring posts on energy meter at house and routing back to inverted on RS485
• Any way to capture loads from both house and pool panel without adding a junction box at main panel to access the wires? Can inverter accept both RS485 input and direct CT input?
• Will inverter send to loads/grid without CT connected

Thanks in advance for your time reading and thoughts.

 

[DaveNSueM]

Oh, I sent a message to EG4 support this morning but @EG4TechSolutionsTeam I have more detail listed in this post. Thanks in advance for thoughts.

 

[EG4TechSolutionsTeam]

So, will the 18kPV only be used to sell power back to the grid, or do you plan to use the export to power loads as well? Also, could you provide a wiring diagram?

 

[DaveNSueM]

So, will the 18kPV only be used to sell power back to the grid, or do you plan to use the export to power loads as well? Also, could you provide a wiring diagram?

Sell to grid/power loads only with future battery for night supplement (my understanding is PV power will flow on grid tie wires and feed loads in my 2 panels with excess flowing back to utility); is my understanding correct on that function?

No to export via load connections in inverter.

Diagrams in first post. Wiring in inverter will be 3 sets of PV wires and grid tie wires.

 

[DaveNSueM]

After contemplating suggestion of 3rd lug connection over the weekend I am moving back to original concept of UL approved Service Rated supply side tap in the 100A pool panel, just before the disconnect breaker.

I am thinking this setup would work although it would show higher than actual power being sent to grid since it would not see the house load (which is where majority of load resides).

@EG4TechSolutionsTeam

• Can multiple CT's be paralled to combine readings from 2 sets of wires?
• Would an EKM single phase (240v 3 wire) meter work with the inverter? The instructions reference a 3-phase meter but no mention of single phase

Inverter is now in my garage awaiting for install and is beautiful!

 

[zanydroid]

Can multiple CT's be paralled to combine readings from 2 sets of wires?

This works electrically with a suitable selection of hardware, and you can DIY research this standard electrical engineering/electrician setup independently.

Now that is somewhat independent to PCS/UL listing or warranty impact.

 

[DaveNSueM]

This works electrically with a suitable selection of hardware, and you can DIY research this standard electrical engineering/electrician setup independently.

Now that is somewhat independent to PCS/UL listing or warranty impact.

Thanks for the reply - could have worded that better to something like are multiple CT's supported / has EG4 tested such a setup. To your point I have come across articles on combining CT's so it sounds intruiging...same for multiple CT's on one energy meter as well.

 

[DougL]

@DaveNSueM , I'm not sure if you will have this problem too but my EG4 18KPV+solar(DC+AC-coupled grid-tied only ) drops the Load output(disconnects) when DC solar PV generation drops at sunset. My Load circuits turn off for 20 seconds or so and then turn back on for a minute or 2 then turn off again. I've resorted to putting it into Standby mode when PV generation goes below 10W. Because this happens in the AM too, I only turn it off Standby after my AC-Coupled solar PV has all micro inverters generating output.

I will be getting a battery in about a month so currently it's a bit of a pain having to daily switch out of and into Standby mode.

 

[DaveNSueM]

@DaveNSueM , I'm not sure if you will have this problem too but my EG4 18KPV+solar(DC+AC-coupled grid-tied only ) drops the Load output(disconnects) when DC solar PV generation drops at sunset. My Load circuits turn off for 20 seconds or so and then turn back on for a minute or 2 then turn off again. I've resorted to putting it into Standby mode when PV generation goes below 10W. Because this happens in the AM too, I only turn it off Standby after my AC-Coupled solar PV has all micro inverters generating output.

I will be getting a battery in about a month so currently it's a bit of a pain having to daily switch out of and into Standby mode.

Thank you for the info, interesting…does support have any ideas on what is going on?

 

[DougL]

Thank you for the info, interesting…does support have any ideas on what is going on?

Opened the ticket last week and they said their firmware guys have an idea and there'd be a firmware update.

 

[DaveNSueM]

Opened the ticket last week and they said their firmware guys have an idea and there'd be a firmware update.

Got mine up and running this past weekend - I am seeing similar behavior early in morning when panels start to come alive; came across it one morning by accident as I was looking at meter. I need to watch at night. Error message says loss of AC (but there was no loss that I could see) and the 300 second timer starts…you can hear relays switch on/off. Overall thrilled with this setup so far - have had beautiful days this week.

Did support get you fixed up, new FW?

 

[EG4TechSolutionsTeam]

Got mine up and running this past weekend - I am seeing similar behavior early in morning when panels start to come alive; came across it one morning by accident as I was looking at meter. I need to watch at night. Error message says loss of AC (but there was no loss that I could see) and the 300 second timer starts…you can hear relays switch on/off. Overall thrilled with this setup so far - have had beautiful days this week.

Did support get you fixed up, new FW?

You may want to change the PV Start Volt from the default 140 to 150 for a smoother transfer. However, feel free to send me a DM of the serial number and I can take a look.

 

[DaveNSueM]

You may want to change the PV Start Volt from the default 140 to 150 for a smoother transfer. However, feel free to send me a DM of the serial number and I can take a look.

DM just sent - thank you.

 

[DougL]

Got mine up and running this past weekend - I am seeing similar behavior early in morning when panels start to come alive; came across it one morning by accident as I was looking at meter. I need to watch at night. Error message says loss of AC (but there was no loss that I could see) and the 300 second timer starts…you can hear relays switch on/off. Overall thrilled with this setup so far - have had beautiful days this week.

Did support get you fixed up, new FW?

I started using email for support but got no reply on the issue and at some point I noticed the voltage in the morning would get up over 200V and the MPPT would kick on then off so I bumped my Start PV Voltage to 240V and the problem has not shown up day or night.