EG4 18KPV Grid Draw

[DevSecOps]

I've replaced some of my other units with a single 18KPV from EG4. The issue that I have is the grid draw from this unit is constantly at 300-400W. I spoke with Signature Solar tech support and they can't seem to figure out why it's so high either. So here's my setup in a nutshell and maybe someone here can shed some insight.

• This is being used on a building which has multiple servers and communications equipment so it has to stay on 100% of the time
• No grid export at all - any excess is sent to EVs through a combination of home assistant and Wallbox
• Since it's a secondary facility it's a sub panel that the inverter feeds.
• Line in is from the main panel. The main panel is not fed at all from the inverter.
• Batteries are connected and high SOC
• PV is connected and providing in excess power
• CTs are connected correctly within the inverter

A typical day uses about 8.7kWh of power from the grid as shown by Sense which has a dedicated circuit monitor on the main panel. Sense is not set up in a solar configuration. It's just a dedicated circuit monitor tracking the "grid draw" from the inverter:



However the 18KPV is only showing 3.1kWh for the same day.



Multiple times throughout the day the 18KPV is showing 0 power being drawn from the grid, where Sense shows that it's continuously drawing power at about 300W. Anyone know why this inverter is drawing so much power from the grid when the batteries are 100% SOC and more than sufficient power is being supplied from solar?

 

[fromport]

Sense does not work with AIO inverters.
Do you also have the sense solar ct's hooked up ?
If that is the case, sense calculates grid usage depending on supply/load side.
I have a combination of grid-tied solar (micro inverters & string inverter) & 2 AIO hybrid inverters & a sense.
I have been communicating with James from sense for a long time and they acknowledge now that sense _only_ works with grid-tie solar & tesla powerwall. Anything else is off. When comparing my monthly utility bills with the sense report over the same time period, they really do not match. Not even close!

 

[SignatureSolarJames]

there is a Powerfactor as well at play here. as far as Sense is concerned, do you have a smart meter? what does the meter read in daily change?

 

[DevSecOps]

Sense does not work with AIO inverters.
Do you also have the sense solar ct's hooked up ?
If that is the case, sense calculates grid usage depending on supply/load side.
I have a combination of grid-tied solar (micro inverters & string inverter) & 2 AIO hybrid inverters & a sense.
I have been communicating with James from sense for a long time and they acknowledge now that sense _only_ works with grid-tie solar & tesla powerwall. Anything else is off. When comparing my monthly utility bills with the sense report over the same time period, they really do not match. Not even close!

I'm actually one of the moderators on the Sense forums. I think you have the wrong idea as to how it's hooked up. Sense is not connected to the inverter at all. Sense is in my main panel with dedicated CTs monitoring the grid supply loads to the inverter. The inverter "grid" side is actually coming from a breaker in the main panel.

 

[Adam De Lay]

It doesn't sound like he's using Sense to monitor the solar aspect at all. He's just using it to monitor power coming from the utility co. I have mine set up the same way. While Sense can monitor some aspects of solar, I let the other dedicated apps handle that aspect. I just wana see what's running from the grid.

 

[DevSecOps]

It doesn't sound like he's using Sense to monitor the solar aspect at all. He's just using it to monitor power coming from the utility co. I have mine set up the same way. While Sense can monitor some aspects of solar, I let the other dedicated apps handle that aspect. I just wana see what's running from the grid.

This is correct. Sense is on the main house and then I use home assistant to pull in inverter values to overlay it all together. Sense doesn't handle solar at all. I'm only concerned with the power draw from the grid by this inverter which is accurately reported by Sense.

 

[fromport]

This is correct. Sense is on the main house and then I use home assistant to pull in inverter values to overlay it all together. Sense doesn't handle solar at all. I'm only concerned with the power draw from the grid by this inverter which is accurately reported by Sense.

As soon as sense has the solar CT's activated, it does not measure the usage ct's but calculates it. And it is off from real life.
But only when solar CT's are enabled. I did write that in my reply, didn't I?

 

[DevSecOps]

As soon as sense has the solar CT's activated, it does not measure the usage ct's but calculates it. And it is off from real life.
But only when solar CT's are enabled. I did write that in my reply, didn't I?

Again... Solar is not enabled on Sense. I am not using Sense for solar. I'm using dedicated circuit monitoring in Sense to record the amount of "grid" power being consumed by the inverter.

 

[fromport]

I'm actually one of the moderators on the Sense forums. I think you have the wrong idea as to how it's hooked up. Sense is not connected to the inverter at all. Sense is in my main panel with dedicated CTs monitoring the grid supply loads to the inverter. The inverter "grid" side is actually coming from a breaker in the main panel.

I have the Sense unit hooked up the same way: directly to main breaker panel.
I have all my inverters (grid tie & aio) hooked up to individual breakers.
They all go through the sense solar ct's in my case.
I would think they would always use the grid CT's as a reference point.
They do if you don't have solar hooked up.
Once you enable solar ct's with sense, instead of taking readings from the utility ct's, they _calculate_ the utility usage and it is off from real life and my utility bill.
Unfortunately...

 

[DevSecOps]

I have the Sense unit hooked up the same way: directly to main breaker panel.
I have all my inverters (grid tie & aio) hooked up to individual breakers.
They all go through the sense solar ct's in my case.
I would think they would always use the grid CT's as a reference point.
They do if you don't have solar hooked up.
Once you enable solar ct's with sense, instead of taking readings from the utility ct's, they _calculate_ the utility usage and it is off from real life and my utility bill.
Unfortunately...

There's a miscommunication as to how I have this hooked up. I think @Adam De Lay understands it, but maybe I'm not explaining this well enough for everyone.

My inverters feed a sub panel. It does not feed the main panel in anyway whatsoever. Sense is in my main panel, not the sub panel. Think of it as an off-grid system with grid power as backup. Sense doesn't have solar enabled. The reason for this is because Sense uses logic to calculate solar based on the loads from the grid plus the CTs connected to the loads going to the inverter. This works when the inverter feeds the main panel and the loads served by THAT panel. In my case, since it's essentially an off-grid system I am using the dedicated circuit monitoring in Sense. All dedicated circuit monitoring does is report, accurately, the amount of power that flows through the CTs going to the inverter. In my case the inverter NEVER sends power back to that panel. In the image that I posted previously you can see that in Sense solar is disabled. I am not using Sense for solar monitoring at all. My solar data is pulled directly from the inverter and combined with Sense in home assistant. This allows me to have very granular data and much more than Sense could ever provide. All I'm trying to do is figure out why the 18KPV draws so much power from the grid when it has battery and solar to consume.

 

[fromport]

As I wrote "if this is the case then ..."
It is not the case, so ignore.

 

[TK1979]

Is it a TOU setting causing the draw from the grid?

 

[DevSecOps]

Is it a TOU setting causing the draw from the grid?

No, and it's a constant draw. I have all of the settings for timed ac charge etc set to 0. It's set to pull from grid in the event of low battery SOC, nothing else.

Signature Solar tech support (who can access the settings remotely on this device) claims that it's because I have the inverter set to "Power Backup" meaning that the EPS output will be uninterruptible. That's what I need to have based on the critical nature of the loads. They claim that it's doing this to buffer load spikes. That would be understandable if it happened on load spikes, but since it's a steady draw I'm not sure what to think. To me, it appears that it's pulling about 30% of the load from the grid and the remainder from the battery/solar.

If it's normal for this unit to pull that much from the grid, then so be it, but I wasn't expecting that much power to be constantly drawn from the grid and I'm wondering if other people with the same unit have noticed this or if there's something I'm missing...

 

[Markus_EG4]

I've replaced some of my other units with a single 18KPV from EG4. The issue that I have is the grid draw from this unit is constantly at 300-400W. I spoke with Signature Solar tech support and they can't seem to figure out why it's so high either. So here's my setup in a nutshell and maybe someone here can shed some insight.

• This is being used on a building which has multiple servers and communications equipment so it has to stay on 100% of the time
• No grid export at all - any excess is sent to EVs through a combination of home assistant and Wallbox
• Since it's a secondary facility it's a sub panel that the inverter feeds.
• Line in is from the main panel. The main panel is not fed at all from the inverter.
• Batteries are connected and high SOC
• PV is connected and providing in excess power
• CTs are connected correctly within the inverter

A typical day uses about 8.7kWh of power from the grid as shown by Sense which has a dedicated circuit monitor on the main panel. Sense is not set up in a solar configuration. It's just a dedicated circuit monitor tracking the "grid draw" from the inverter:

View attachment 154770

However the 18KPV is only showing 3.1kWh for the same day.

View attachment 154771

Multiple times throughout the day the 18KPV is showing 0 power being drawn from the grid, where Sense shows that it's continuously drawing power at about 300W. Anyone know why this inverter is drawing so much power from the grid when the batteries are 100% SOC and more than sufficient power is being supplied from solar?

I would like to see the data from the inverter, the monitoring system. If you want you can PM me and I can look into this and see what going on

 

[DevSecOps]

So, as a follow up ... @Markus_SignatureSolar had engineers take a look at my inverter and they noticed that Fast Zero Export was causing the inverter to draw power in order to prevent it from sending power back. EG4 pushed a new firmware to the device in order to remedy this issue. It now has an audible relay click when switching to grid power to charge a low SOC battery or to switch to grid. The only difference is that the inverter is now in EPS mode all the time unless pulling from the grid. I assume this is normal.

Previous Firmware: FAAB-0e0e
New Firmware: FAAB-1010

If anyone else experiences this issue it looks like you might need the new firmware version.

 

[Adam De Lay]

So, as a follow up ... @Markus_SignatureSolar had engineers take a look at my inverter and they noticed that Fast Zero Export was causing the inverter to draw power in order to prevent it from sending power back. EG4 pushed a new firmware to the device in order to remedy this issue. It now has an audible relay click when switching to grid power to charge a low SOC battery or to switch to grid. The only difference is that the inverter is now in EPS mode all the time unless pulling from the grid. I assume this is normal.

Previous Firmware: FAAB-0e0e
New Firmware: FAAB-1010

If anyone else experiences this issue it looks like you might need a new firmware version.

I guess that makes sense. It's drawing a buffer to prevent anything from being exported. Is there a way to set the buffer value?

What's the inverter pulling from the grid now?

 

[DevSecOps]

I guess that makes sense. It's drawing a buffer to prevent anything from being exported. Is there a way to set the buffer value?

What's the inverter pulling from the grid now?

Absolutely nothing. It's now using the relays to disengage the grid unless it's needed. This is why, I assume, it's going into EPS. It's acting as if there's grid loss but it knows there's not.

 

[Heritage1]

I'm guessing this probably wouldn't work for those of us who are back-feeding the main panel to power those breakers (which we don't have in our critical load panel and have the CTs between the meter and the main panel).
To ensure zero export in that type of setup there probably needs to be some regular import from the grid.

 

[DevSecOps]

I'm guessing this probably wouldn't work for those of us who are back-feeding the main panel to power those breakers (which we don't have in our critical load panel and have the CTs between the meter and the main panel).
To ensure zero export in that type of setup there probably needs to be some regular import from the grid.

I think this was a bug specifically with the fast zero export setting. You can still tell the inverter not to export, without fast zero export, and it likely keeps the prior behavior. I haven't tested that however.

 

[Heritage1]

So this new firmware has fixed the fast export? @Markus_SignatureSolar
I don't see it on the 18kPV app yet.