Gridboss cutover time from FlexBoss21 Inverter to Grid

[skimandan]

Howdy Pardners,

I passed my AHJ inspection yesterday and they pulled AC disconnect between FlexBoss and GridBoss and it shut down power at my house for more than 10ms as the GridBoss switched from FlexBoss supplied power to the main grid. Maybe 1 second, so my home office worker got to yell at inspector for killing power without warning during a zoom call. Inspector didn't touch another thing after that.
Is this typical, nominal, maximal, per spec, per manual, intended, inferred, hinted at?

I was surprised that I was surprised that Grid power was so delayed that I had to reset my microwave clock.

Discuss.

 

[Crowz]

Howdy Pardners,

I passed my AHJ inspection yesterday and they pulled AC disconnect between FlexBoss and GridBoss and it shut down power at my house for more than 10ms as the GridBoss switched from FlexBoss supplied power to the main grid. Maybe 1 second, so my home office worker got to yell at inspector for killing power without warning during a zoom call. Inspector didn't touch another thing after that.
Is this typical, nominal, maximal, per spec, per manual, intended, inferred, hinted at?

I was surprised that I was surprised that Grid power was so delayed that I had to reset my microwave clock.

Discuss.

Hope not, my sungold/srne clone which cost only $1600 doesn't even blink the lights when the power goes out. Pretty sad for that much money if so.

 

[timselectric]

That's not a standard test scenario.
It's actually pretty impressive that it recovered that fast , or at all. From a "system failure" scenario.

 

[skimandan]

That's not a standard test scenario.
It's actually pretty impressive that it recovered that fast , or at all. From a "system failure" scenario.

Thank you for your counsel.
I will sink this thread to the bottom of the ocean and allow it to turn into a coral reef.

 

[mciholas]

I passed my AHJ inspection yesterday and they pulled AC disconnect between FlexBoss and GridBoss and it shut down power at my house for more than 10ms as the GridBoss switched from FlexBoss supplied power to the main grid.

Grid was up and connected to the GB? Since you were undergoing an inspection, maybe you weren't allowed to feed the grid yet?

If grid was powered and connected, I'm not sure why the grid didn't power the house.



With grid up, the grid relay (right most above) should be closed as shown. That puts the grid directly connected to the backup panel, which is the house loads. Drop the FB connection, the grid is still connected to the house unless the GB decides to open that relay for some reason on FB drop. So why would the grid not power the house? Or to ask it another way, why would the GB open the grid relay when the FB goes away? The grid relay is the ONLY way the GB can stop grid power reaching the backup panel.

So I am confused why power dropped. It feels like it should not have done that.

Is this typical, nominal, maximal, per spec, per manual, intended, inferred, hinted at?

I'm going to go with "no" on that as my opinion. Or more precisely, I would want it not to. Maybe this is some corner case EG4 didn't account for in the software? I'd really rather not have a system where an inverter going offline means the GB takes the entire house down, even for 1 second.

Mike C.

 

[rhorer]

…pulled AC disconnect between FlexBoss and GridBoss and it shut down power at my house for more than 10ms as the GridBoss switched from FlexBoss supplied power to the main grid. Maybe 1 second,

Did you go through the information on pages 32-35 of the GridBoss manual, particularly making sure the "Grid Boss" box is checked on all the appropriate configuration screens and that the communication cables are connected correctly? Are firmwares up to date?

As @timselectric noted, pulling the AC disconnect between the inverter and the GridBoss is not a standard test condition. If the inverter were to fail then either that failure would be communicated over the comms cables or the comms would go dead at the same time as the inverter's AC output. I can see how having the inverter telling the GridBoss that everything is fine would delay the GridBoss's switchover.

 

[mciholas]

I can see how having the inverter telling the GridBoss that everything is fine would delay the GridBoss's switchover.

But there is no GridBOSS "switchover" that needs to happen. The GB should have the grid relay closed when the FB is operating, and that relay should remain closed when the FB goes away. The GB doesn't have to do anything to keep the house operating.

For the house to go dark when the FB breaker was opened, the GB had to explicitly drop the grid relay (see diagram above). That is the GB decided to make the house go dark. Why did it do that? And why did it return power 1 second later?

That does not seem right to me, something is off with the install or the control logic in the GB.

Maybe the GB was in "off grid" mode (is that a thing?) and the grid relay wasn't engaged at all? That's the only simple explanation I can find.

Mike C.

 

[rhorer]

Maybe the GB was in "off grid" mode (is that a thing?) and the grid relay wasn't engaged at all? That's the only simple explanation I can find.

That was the scenario I was assuming when I wrote my reply. Although I can see your point that in other configurations, the grid relay would already be closed and could/should remain closed.

That does not seem right to me, something is off with the install or the control logic in the GB.

Definitely another possibility to look into.

 

[skimandan]

Just getting back to it after a long weekend.
I was running in "self consumption" mode when the A/C disconnect was pulled. I expected the same result as you all, but no. That is why I posted. Perhaps in that mode the GridBoss opens the relay connecting the grid unless it is needed? Perhaps I am EG4's most accomplished unpaid beta tester? Perhaps because I have it set to not sellback to the utility it opened the relay?
Honestly, this "bug" does not cost me any production and is probably just another manual/firmware/configuration gremlin that I keep discovering. I guess everyone else expects this? I was surprised Will's recent review of the system didn't offer any caution regarding this, but it might just be the norm with inverters.

 

[PhilIA]

I was under the impression if you have "off-grid" selected, the grid relay is open unless it calls for charging the battery, or PV/battery power is not enough to keep up with demand. In that case it closes the grid relay and cuts PV/battery power. No blending of PV/battery with grid power in off-grid mode.

 

[skimandan]

I have not activated "off grid" mode, and would not expect the inverter to quickly switch to grid if i did.

 

[PhilIA]

Mis-read what you posted

 

[EG4TechSolutionsTeam]

Howdy Pardners,

I passed my AHJ inspection yesterday and they pulled AC disconnect between FlexBoss and GridBoss and it shut down power at my house for more than 10ms as the GridBoss switched from FlexBoss supplied power to the main grid. Maybe 1 second, so my home office worker got to yell at inspector for killing power without warning during a zoom call. Inspector didn't touch another thing after that.
Is this typical, nominal, maximal, per spec, per manual, intended, inferred, hinted at?

I was surprised that I was surprised that Grid power was so delayed that I had to reset my microwave clock.

Discuss.

Can you post some screenshots of your settings?
We would like to make sure you have the best configuration for the transfer to be seamlessly.

 

[skimandan]

Can you post some screenshots of your settings?
We would like to make sure you have the best configuration for the transfer to be seamlessly.

Yes I'll pm you the .pdf dumps from the monitor for both the GridBoss and FlexBoss so I don't have to redact my inverter info.

 

[Will Prowse]

Howdy Pardners,

I passed my AHJ inspection yesterday and they pulled AC disconnect between FlexBoss and GridBoss and it shut down power at my house for more than 10ms as the GridBoss switched from FlexBoss supplied power to the main grid. Maybe 1 second, so my home office worker got to yell at inspector for killing power without warning during a zoom call. Inspector didn't touch another thing after that.
Is this typical, nominal, maximal, per spec, per manual, intended, inferred, hinted at?

I was surprised that I was surprised that Grid power was so delayed that I had to reset my microwave clock.

Discuss.

Oh shoot, maybe somethings wrong. I tested mine in the workshop and the transfer time was perfect. Pc and heat pumps were good. Might be settings. Or setup.

 

[timselectric]

I think that people are missing the important part.
This system was not commissioned yet. It was in the electrical inspection step.
It shouldn't have been connected with the grid (so I assume that it wasn't). (Grid relay open)
This switch over shouldn't have even happened. But it did, and was actually pretty quick for the circumstances.

 

[skimandan]

This system was not commissioned yet. It was in the electrical inspection step.
It shouldn't have been connected with the grid (so I assume that it wasn't). (Grid relay open)

The system was/is operating in self-consumption zero sellback mode while awaiting POCO net meter swap. Interaction with grid should have been limited to A/C passthrough and A/C charging.

 

[timselectric]

The system was/is operating in self-consumption zero sellback mode while awaiting POCO net meter swap. Interaction with grid should have been limited to A/C passthrough and A/C charging.

Yup
And it probably completely freaked out. When it lost power from the flexboss, but communication said everything was normal.
I think that it reacted better than should have been expected.

 

[skimandan]

Yup
And it probably completely freaked out. When it lost power from the flexboss, but communication said everything was normal.
I think that it reacted better than should have been expected.

I agree.
That's why I'd rather folks focus on the issues that are happening with my system everyday:

S

Thread 'FlexBoss21 / GridBoss Issue List'

Jan 29, 2025

Howdy folks,
First solar setup. Everything from the panels, mounts, j-boxes, disconnect switches, wallmount batteries, etc worked exactly as planned with exception of the GridBoss/FlexBoss combo. I've had my gridboss / flexboss system in production for a week, trying to fine tune my system so I don't need to touch it again for a decade or so. I have encountered a few features that do not work per spec, or in the way advertised, or are just missing completely. Signature Solar has guided me through a number of undocumented workarounds to some of the issues, what I lovingly call "hacks" that...

• skimandan
• Replies: 224
• Forum: Complaint Corner

• 

 

[Tommytwotone]

Yup
And it probably completely freaked out. When it lost power from the flexboss, but communication said everything was normal.
I think that it reacted better than should have been expected.

I believe it would set an E030 Gridboss breaker open fault. As such it must be programmed to know when the breaker is open.

So my guess is the communication reflects the loss of the inverter input on the AC buss and the system understands what has happened at least the what but maybe not the why. AHJ switches it off vs breaker trip etc.

The system as a whole, Gridboss with Flexboss at least, seems to have switchover issues at times. Or at least mine does. At times the system drops power when going to or from grid when it reaches 20% SOC for switching to grid or an SOC where it should go back to inverters .

But mine has also had issues with random shutdowns for typically a couple seconds.

I mention the related issues in case it helps skimandan.

 

[jrkd2015]

I believe it would set an E030 Gridboss breaker open fault. As such it must be programmed to know when the breaker is open.

So my guess is the communication reflects the loss of the inverter input on the AC buss and the system understands what has happened at least the what but maybe not the why. AHJ switches it off vs breaker trip etc.

The system as a whole, Gridboss with Flexboss at least, seems to have switchover issues at times. Or at least mine does. At times the system drops power when going to or from grid when it reaches 20% SOC for switching to grid or an SOC where it should go back to inverters .

But mine has also had issues with random shutdowns for typically a couple seconds.

I mention the related issues in case it helps skimandan.

Do you have the grid boss and flex boss? I am interested in them both.

 

[Tommytwotone]

Do you have the grid boss and flex boss? I am interested in them both.

Yes. I have both.

 

[jrkd2015]

Yes. I have both.

How long have you had them? How many solar panels? Type and size of battery bank? Would you buy them again or recommend them? Thanks!

 

[Tommytwotone]

How long have you had them? How many solar panels? Type and size of battery bank? Would you buy them again or recommend them? Thanks!

Sorry I did not see this. We went live off grid in December. I am hard pressed to recommend them today due to ongoing issues. I had some issues that the firmware update may have fixed but we received PTO, so we could connect to the grid and sell back, and now the inverters wont push a watt to grid. Very frustrated.

 

[CaySol]

Sorry I did not see this. We went live off grid in December. I am hard pressed to recommend them today due to ongoing issues. I had some issues that the firmware update may have fixed but we received PTO, so we could connect to the grid and sell back, and now the inverters wont push a watt to grid. Very frustrated.

Share your settings.