Gridboss with Flexboss not handling 21kW pass-through

[jeff.lankford]

Key point was "different software stack", while still conforming to US electrical code. I guess I am assuming the 18kpv is similar or the same since I believe that point was made by EG4's CEO, so it would be more telling to look at a product that uses similar components built by a different OEM with a different software stack controlling the relay.

Those look like similar Churod relays except 830v instead of 1000v, is that a Gridboss or 18pkv?

Churods with cooling fan on Sol-Ark as found on this site:

View attachment 275934

That's from an 18K. No fan evident near the relays, but I didn't pop a cover. That compartment is sealed on the 18K, and all the cooling fans are blowing on heat sinks outside/behind the sealed compartment. It is possible these relays are mounted on heat sinks that extend into the back area.

<EDIT> it's not possible for the relays to be on heat sinks... they are positioned below the rear heat sink/radiator compartment.

 

[Quattrohead]

Here is the area in question for those that are technically interested.
And yes I know of one that was welded shut on a unit, probably from reversing L1 and L2 in a parallel setup.

 

[mciholas]

https://www.churodamericas.com/wp-content/uploads/2021/07/char-a200efbc8cchar-a150h-series.pdf

Contact rating is 50 A make/break, 200 A carry. So not great at interrupting heavy currents.

Activate time is 35 ms, drop time is 30 ms, so no way to really do that in AC cross over time, so the contacts will take a beating interrupting an overload.

Mike C.

 

[jharrell]

Contact rating is 50 A make/break, 200 A carry. So not great at interrupting heavy currents.

Arcing while switching under heavy loads is a primary cause of welded contacts, would be better to leave the relay connected and let it resistively heat rather than try and be a circuit breaker.

This is why I asked how a Sol-Ark handled it with similar relays. I don't believe any of the mobile inverters I have dealt with disconnect on pass through OCP (Magnum, Victron) and let the circuit breakers deal with it, but might fault on a welded relay detecting continuity when commanded to disconnect. I did have an issue with my Magnum disconnecting on a RV air conditioner start but that was caused by voltage sag from over current not actual overcurrent detection.

 

[Quattrohead]

https://www.churodamericas.com/wp-content/uploads/2021/07/char-a200efbc8cchar-a150h-series.pdf

Contact rating is 50 A make/break, 200 A carry. So not great at interrupting heavy currents.

Activate time is 35 ms, drop time is 30 ms, so no way to really do that in AC cross over time, so the contacts will take a beating interrupting an overload.

Mike C.

Remember each one is handling 100 amps, one per leg.

 

[mciholas]

Remember each one is handling 100 amps, one per leg.

Each leg is handling 120 VAC per leg, but the full 200 amps goes through each leg (or whatever the fault current is, which could be much higher).

Mike C.

 

[slowroller]

Probably my last update on this issue...
LuxPower loaded IAAB-1200 V6 on 2/7. I have not seen any issues. From my perspective, I cannot see a difference between this and V5.
S2 has closed the ticket. All good.

 

[skimandan]

Congrats and thank you for pursuing this!
If you think of it, can you post on here when EG4 updates the next firmware to verify the fix made it into production firmware? My current production version is IAAB-1100.

 

[jeff.lankford]

Congrats and thank you for pursuing this!
If you think of it, can you post on here when EG4 updates the next firmware to verify the fix made it into production firmware? My current production version is IAAB-1100.

You can monitor for that at this forum. Looks like you can even add a subscribe just for GB updates if you want to...

Firmware Updates

Stay current with the latest firmware releases and enhancements to optimize your EG4 products' performance.

forum.eg4electronics.com

 

[skimandan]

You can monitor for that at this forum. Looks like you can even add a subscribe just for GB updates if you want to...

Firmware Updates

Stay current with the latest firmware releases and enhancements to optimize your EG4 products' performance.

forum.eg4electronics.com

No thanks. I trust Will moderating this site. And more critical eyeballs to hold everyone accountable.

 

[jeff.lankford]

No thanks. I trust Will moderating this site. And more critical eyeballs to hold everyone accountable.

You don't want to trust the EG4 operated site where they publish all firmware update notifications and the detailed release notes? You literally asked for a notification for when this fix makes it into an official production release.

 

[skimandan]

Sorry bro I probably was not clear and no offense to you trying to help was intended. I want slowroller to verify that this fix is actually in the next firmware update. I don’t want a notification that there is an updated firmware. I don’t trust that the firmware notes will be written in any way that shows that they made a mistake. I trust random internet dude slowroller far more right now.
You are correct that my trust in EG4 documentation and firmware and testing is shaky. Look at my other posts / threads. Or just this thread.
Sorry for ranting. It’s sunny here and I should stop yelling at clouds when there are none.

 

[jeff.lankford]

Sorry bro I probably was not clear and no offense to you trying to help was intended. I want slowroller to verify that this fix is actually in the next firmware update. I don’t want a notification that there is an updated firmware. I don’t trust that the firmware notes will be written in any way that shows that they made a mistake. I trust random internet dude slowroller far more right now.
You are correct that my trust in EG4 documentation and firmware and testing is shaky. Look at my other posts / threads. Or just this thread.
Sorry for ranting. It’s sunny here and I should stop yelling at clouds when there are none.

Cool, and I understand.

 

[slowroller]

Congrats and thank you for pursuing this!
If you think of it, can you post on here when EG4 updates the next firmware to verify the fix made it into production firmware? My current production version is IAAB-1100.

I don't have any reason to believe that I will know when it is released to the public.

 

[RARankin]

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.

Thanks for this thread and working with EG4 on a solution.

I had a similar issue yesterday. I have two Gridbosses (each with their own Flexboss21), each GB feeds a 200a panel on backup loads. The Heat pump condenser is in a smart port and the backup heat is in another. When in defrost with the backup heat (15kw) running, the condenser kicked on as expected.... and then the GB killed the condenser smart port with an over current. Fault error was "MIDBOX_FAULT_011: Smart Port 2 over current."

Its been running since the beginning of the year w/o issue, and has not tripped again since yesterday.

As for a plan for my HVAC staying functional on battery I have the 24v and fan on a separate breaker in the backup loads panel and the backup heat set to disable fairly quickly from the smart port if I end up on battery. I do wish they had a better "disable when grid offline" option for smart ports. Or allow us to use the extra relay in the GB for killing 24v power to the relays turning on the backup heat.

Andrew

 

[Brucey]

Thanks for this thread and working with EG4 on a solution.

I had a similar issue yesterday. I have two Gridbosses (each with their own Flexboss21), each GB feeds a 200a panel on backup loads. The Heat pump condenser is in a smart port and the backup heat is in another. When in defrost with the backup heat (15kw) running, the condenser kicked on as expected.... and then the GB killed the condenser smart port with an over current. Fault error was "MIDBOX_FAULT_011: Smart Port 2 over current."

Its been running since the beginning of the year w/o issue, and has not tripped again since yesterday.

As for a plan for my HVAC staying functional on battery I have the 24v and fan on a separate breaker in the backup loads panel and the backup heat set to disable fairly quickly from the smart port if I end up on battery. I do wish they had a better "disable when grid offline" option for smart ports. Or allow us to use the extra relay in the GB for killing 24v power to the relays turning on the backup heat.

Andrew

Seems like just a single fb21 supporting a 200A panel with 12kW of battery inversion at night is going to cause issues especially with strip heaters etc causing significant increases in demand., that may not be seen with two units per panel/grid boss? Basically too close to the edge?

 

[RARankin]

Seems like just a single fb21 supporting a 200A panel with 12kW of battery inversion at night is going to cause issues especially with strip heaters etc causing significant increases in demand., that may not be seen with two units per panel/grid boss? Basically too close to the edge?

Intention is to have the strip heat smart port disabled if on battery without grid.

 

[skimandan]

Intention is to have the strip heat smart port disabled if on battery without grid.

Update on Smart Loads.
The circled settings worked as expected. The one on the left turns off smart ports when grid is down. The manual makes it seem like they are equivalent, but they are not. I have not tested what happens with battery parameters yet.
View attachment 274612

Use the one on the left. It is not clear. I have a thread on it.

S

Post in thread 'Gridboss Smart Loads'

Jan 31, 2025

Update on Smart Loads.
The circled settings worked as expected. The one on the left turns off smart ports when grid is down. The manual makes it seem like they are equivalent, but they are not. I have not tested what happens with battery parameters yet.

• skimandan

• 

 

[Tommytwotone]

Thanks for this thread and working with EG4 on a solution.

I had a similar issue yesterday. I have two Gridbosses (each with their own Flexboss21), each GB feeds a 200a panel on backup loads. The Heat pump condenser is in a smart port and the backup heat is in another. When in defrost with the backup heat (15kw) running, the condenser kicked on as expected.... and then the GB killed the condenser smart port with an over current. Fault error was "MIDBOX_FAULT_011: Smart Port 2 over current."

Its been running since the beginning of the year w/o issue, and has not tripped again since yesterday.

As for a plan for my HVAC staying functional on battery I have the 24v and fan on a separate breaker in the backup loads panel and the backup heat set to disable fairly quickly from the smart port if I end up on battery. I do wish they had a better "disable when grid offline" option for smart ports. Or allow us to use the extra relay in the GB for killing 24v power to the relays turning on the backup heat.

Andrew

Intention is to have the strip heat smart port disabled if on battery without grid.

Andrew,

We have some of the same equipment and issues to address. With as much as you have split up your control of the electric furnaces functions I wonder the following based on my HVAC background.

In your instance a way to accomplish the on grid only function for strip heat might be to have a 24v transformer powered by grid that closes a contact only when grid is present. This would also allow you to have an external contactor take the brunt of the work. I have heard of some issues with contactors in the GB.

I plan to do something like that with my water heater control. I will use a delay on make so the GB port contactor can close without load then the external contactor will close a few seconds later.

As a question would the 15kw (62amps) plus the condenser at say 18 amps totaling 80amps not push the inverter/GB to draw from grid? Is that the way you intend it?

 

[RARankin]

Andrew,

We have some of the same equipment and issues to address. With as much as you have split up your control of the electric furnaces functions I wonder the following based on my HVAC background.

In your instance a way to accomplish the on grid only function for strip heat might be to have a 24v transformer powered by grid that closes a contact only when grid is present. This would also allow you to have an external contactor take the brunt of the work. I have heard of some issues with contactors in the GB.

I plan to do something like that with my water heater control. I will use a delay on make so the GB port contactor can close without load then the external contactor will close a few seconds later.

As a question would the 15kw (62amps) plus the condenser at say 18 amps totaling 80amps not push the inverter/GB to draw from grid? Is that the way you intend it?

I had the same thought on the transformer, I don't have a non-backup panel so I didn't have a good way to grab grid power to make it happen.

Yup I'll go over what the inverter can provide, my main goal is for backup power (with strip heat disabled) and once I have solar installed to reduce my dependence on the grid. If the Grid is up, I'm OK with using it.