Gridboss with Flexboss not handling 21kW pass-through

[slowroller]

New Member, first post.

I installed a Gridboss, Flexboss and two PowerPro batteries on new years eve. No PV yet, running in backup mode. There is a 200A disconnect between grid and Gridboss. Whole house load panel is powered from Backed up Loads output on the Gridboss.



For the first week, all was good. Charged batteries, disconnected grid, house was powered by batteries/inverter. Tested 5 ton HVAC (heat pump) while running water heater. LED lights flickered, but everything worked. Turned the grid back on, and batteries charged. All good.

Something happened, and the house went dark. Flexboss still blinks green "normal" light. No power to the house. I opened the hybrid 1 breaker and put the Gridboss into bypass. That worked. Rebooted system and started looking over the data. I think my emergency heat kicked in, and needed an additional 20kW of power for the heat strips. The Gridboss did not handle this well. It crashed and stayed crashed until I intervened a few hours later. Went back to normal mode, and it happened again. I have better data for that one. See attached graph.



I understand that this would be too much load for the inverter. (I plan to address this by using a smart load to enable/disable the heat strips) But, I thought the Gridboss was supposed to be able to handle up to 200A of pass-through. Why would this load shut things down?

I called support at S2. No solution, but they said they would escalate the ticket. That was two days ago, and I have not heard back.

I have attached some labeled photos. Any suggestions would be greatly appreciated.

UPDATE/TLDR: Surge current to start the 5 ton HVAC was exceeding 200A and tripping the OC protection in the GridBoss. The OCP profile was updated to allow short surges exceeding 200A. This was solved in IAAB-1200 V6 firmware for GB.

 

[wpns]

Are you in backup mode or grid shaving?

 

[slowroller]

Running in backup mode. Would this make a difference? S2 did most of the config OTA. The settings are a bit hard to decipher.

 

[slowroller]

A little more info to add to the thread:
I added a ground bond to the grid boss, to see if anything would change. I thought there might be an instrumentation problem that was causing a false reading in the current sensors. It still crashes when the emergency heat on my HVAC kicks on. Bond removed.

 

[blueforce]

Not an HVAC specialist here but my backup heat strips turn on whenever my heat pump goes into a defrost cycle. I'd make sure you don't need those heat strips for the defrost before moving them to smart load.

I run hybrid mode so grid-assist covers the difference. Do you have your interconnect agreement, or at least the submission for it, yet?

 

[slowroller]

My heat strips kick in whenever we need heat and the temperature is below 30 degrees. My plan is to come up with a way to use the smart loads to enable or disable the HVAC, without directly switching the power to the air handler. This is a future task that I won't be moving on to until the house can remain powered without manual intervention.

Please correct me if I don't understand what you mean, or how the gridboss works. In backup mode, I am attempting to use the grid for ALL power needs. Only if the grid is off, will I use the inverter. If I disable the heat strips, this all works fine. I can run from grid, and I can turn off the grid and still have power. (from batteries/inverter). I have even tested running the water heater and 5 ton HVAC at the same time on the inverter. (without heat strips)

My question is, why can't the gridboss handle 21kW of passthrough from the grid? From the manual, I think it should.

 

[blueforce]

My heat strips kick in whenever we need heat and the temperature is below 30 degrees. My plan is to come up with a way to use the smart loads to enable or disable the HVAC, without directly switching the power to the air handler. This is a future task that I won't be moving on to until the house can remain powered without manual intervention.

Please correct me if I don't understand what you mean, or how the gridboss works. In backup mode, I am attempting to use the grid for ALL power needs. Only if the grid is off, will I use the inverter. If I disable the heat strips, this all works fine. I can run from grid, and I can turn off the grid and still have power. (from batteries/inverter). I have even tested running the water heater and 5 ton HVAC at the same time on the inverter. (without heat strips)

My question is, why can't the gridboss handle 21kW of passthrough from the grid? From the manual, I think it should.

That question is beyond my scope of knowledge but something is wrong. EG4 and Signature Solar are off for the weekend but tag em anyways @EG4TechSolutionsTeam

 

[jeff.lankford]

Have you looked at the Event History in the web monitor to see what error / alarm is logged at the time of the crash? It might give a clue as to why the pass through isn't handled.

 

[ChrisG]

Have you looked at the Event History in the web monitor to see what error / alarm is logged at the time of the crash? It might give a clue as to why the pass through isn't handled.

@jeff.lankford Is there an event history for the gridboss? I know there would be for the inverters but he’s not using them, just passthrough the 200a within the gridboss.

 

[jeff.lankford]

@jeff.lankford Is there an event history for the gridboss? I know there would be for the inverters but he’s not using them, just passthrough the 200a within the gridboss.

I have no idea. I have an 18K, not a GB/FB combo. But I just thought that any logged errors would be located there, and worth checking. There's a FB in his configuration, so still worth looking to see if any errors are logged, by any system components.

<EDIT>
The 21 kW crash point is suspiciously close to the 90A limit of the Gridboss' hybrid inverter ports. I'm thinking of looking for errors because the GB is possibly not treating this scenario as a grid pass-through operation (due to a wrong setting??), but instead the GB thinks the inverter is contributing to the loads somehow. I realize the graphs show zero battery consumption, so the inverter is not actually providing the power. Just looking for clues...

 

[slowroller]

That's a good idea. In the event history, I never see anything from the "event". When I shut things down to restart, the Gridboss shows a "Grid frequency abnormality" and the inverter will say "No AC Connection" and/or "Grid Boss Breaker Open". Again, those are generated during the manual intervention, not during the crash.

 

[slowroller]

The 21 kW crash point is suspiciously close to the 90A limit of the Gridboss' hybrid inverter ports. I'm thinking of looking for errors because the GB is possibly not treating this scenario as a grid pass-through operation (due to a wrong setting??), but instead the GB thinks the inverter is contributing to the loads somehow. I realize the graphs show zero battery consumption, so the inverter is not actually providing the power. Just looking for clues...

Based on your suggestion, I did a little more digging on the Flexboss side. If not using the Gridboss, the "Max AC Bypass" is 90A (21.6kW). I am beginning to smell a software/config issue, as you suggested. Maybe not even in the Gridboss. What if the Inverter sees the current exceeding 90A and throws a flag that shuts things down? (even though the Gridboss should be in charge)

 

[jeff.lankford]

What if the Inverter sees the current exceeding 90A and throws a flag that shuts things down? (even though the Gridboss should be in charge)

Exactly. I didn't state it, but I was wondering about the inverter throwing an error that causes the GB to shutdown.

That Flexboss pass through spec shouldn't apply here, but with a bad configuration, it could be related. You're not using CTs with the Flexboss, are you? The GB manual states those shouldn't be used. Also, did you double check that the Gridboss setting on the Flexboss is enabled?

 

[slowroller]

I did not install the Flexboss CTs. That's one of the first things Signature Solar asked.

I have seen that the Gridboss(MID) was enabled. I am trying to verify that, but I can't find that setting. Looking.

 

[slowroller]

I did not install the Flexboss CTs. That's one of the first things Signature Solar asked.

I have seen that the Gridboss(MID) was enabled. I am trying to verify that, but I can't find that setting. Looking.

Check.

 

[slowroller]

Can anyone shed light on how to set the CT parameters in the Flexboss when using a Gridboss? I am wondering if the measurement should be set to zero, since the CTs are not used. Here are the choices:





And My settings:

 

[wpns]

Can anyone shed light on how to set the CT parameters in the Flexboss when using a Gridboss? I am wondering if the measurement should be set to zero, since the CTs are not used. Here are the choices:

View attachment 269606



And My settings:

View attachment 269607

'Meter' is when you have an external RS485/Modbus meter like the Acrel which reports power flow connected to (in the 18Kpv case) the 'Meter485' terminals. I assume you don't have one. If you are not supposed to use CTs then leave it at '<Empty>'

 

[slowroller]

Thank you. That makes sense. But, "empty" is not an option, it generates a parameter error when you try to set it. Only option 0 and 1 are SET-able.

 

[455dan]

New Member, first post.

I installed a Gridboss, Flexboss and two PowerPro batteries on new years eve. No PV yet, running in backup mode. There is a 200A disconnect between grid and Gridboss. Whole house load panel is powered from Backed up Loads output on the Gridboss.

View attachment 268564

For the first week, all was good. Charged batteries, disconnected grid, house was powered by batteries/inverter. Tested 5 ton HVAC (heat pump) while running water heater. LED lights flickered, but everything worked. Turned the grid back on, and batteries charged. All good.

Something happened, and the house went dark. Flexboss still blinks green "normal" light. No power to the house. I opened the hybrid 1 breaker and put the Gridboss into bypass. That worked. Rebooted system and started looking over the data. I think my emergency heat kicked in, and needed an additional 20kW of power for the heat strips. The Gridboss did not handle this well. It crashed and stayed crashed until I intervened a few hours later. Went back to normal mode, and it happened again. I have better data for that one. See attached graph.

View attachment 268565

I understand that this would be too much load for the inverter. (I plan to address this by using a smart load to enable/disable the heat strips) But, I thought the Gridboss was supposed to be able to handle up to 200A of pass-through. Why would this load shut things down?

I called support at S2. No solution, but they said they would escalate the ticket. That was two days ago, and I have not heard back.

I have attached some labeled photos. Any suggestions would be greatly appreciated.

Wow, yeah, no matter how we slice it 200 amp, 240 VAC pass through is actually a max of 48KW.

20KW + of grid pass through should be a cake walk for the GridBoss.


(So far) less than a month, the 18K PV has been able to pass through over 27KW at several times and ~ 120 KWH in a day, the relays/contactors are not even getting a little warm. Sure sounds like all that is needed is to tweak some code on the Gridboss or Flexboss.

Here is hoping S2 can get a quick fix update to you asap.

ps. your system Install looks Great!

 

[wpns]

Thank you. That makes sense. But, "empty" is not an option, it generates a parameter error when you try to set it. Only option 0 and 1 are SET-able.

So if you have no CTs connected, set it to CT and they won't generate a signal, so the inverter shouldn't do anything with it.

I'm not going to try it on mine because I'm 600 miles away, and I don't want to take any chances.

 

[slowroller]

Here is hoping S2 can get a quick fix update to you asap.

I hope so too. I don't know how long it usually takes. My ticket was escalated on January 6th. Still remains unassigned on Jan 13th. (as of 10am)

 

[SignatureSolarJess]

I called support at S2. No solution, but they said they would escalate the ticket. That was two days ago, and I have not heard back.

Hi! If you'd like to shoot me a dm with the email address you used to reach out to us, I can check on this for you!

 

[EG4TechSolutionsTeam]

Would you be able to send us the serial numbers through DM so that we can look into this?

 

[slowroller]

Both Requested DM's sent.

 

[slowroller]

Update: S2 installed new firmware on the GridBoss. Now, the unit does not always trip when exceeding 20kW draw from grid. It still trips occasionally. Working with S2/EG4 on a solution. When it trips, it does not self-recover. So, I can't leave the system unattended unless it is in bypass mode. Has anyone else seen this issue with the GridBoss? Or, has anyone had success in passing 30kW though the GridBoss? It should be good up to 200A, right?