(Resolved) Growatt injecting 5kW into my critical load even without solar input

[ericatb8a]

I've been using a SunGoldPower 10kW offgrid AIO in Utility Bypass mode for my critical loads, trouble-free for weeks. Recently added a Growatt MIN 5000TL-X to the mix, connected via a 20A breaker, feeding into my critical loads. During an early morning test with only ~200W from solar, all was fine. Post-test, I disconnected solar and stepped away, thinking the Growatt would be inert.

After about 20 minutes, I came back to a burning smell. Logs showed a 5.5kW surge from the Growatt, apparently pulling from utility, overwhelming my off-grid setup and risking an electrical fire.

Anyone else faced this or know why it might happen?

9/26 Thursday Update: The burning smell issue returned on Tuesday morning, even though Growatt was disconnected since Sunday. This confirms the problem is with SGP, which we've now taken offline. We've been running on utility power without any issues for almost 48 hours. I'll be reporting this to SGP.

**Update 10/17/24:** After further tests and a consultation with an AC technician, I've identified the issue with my MrCool Split AC system. The problem arises from rapidly cycling the unit on and off. Apparently, this can cause the small oil-filled motors inside to enter a state of confusion, leading to attempts to start without fully succeeding, which in turn can cause them to heat up thus the burnt oil smell. This issue persists even when the AC is not on but the power cicuit is energized. The solution is to completely shut down the AC's power circuit anytime that I might need to cycle the house power. And wait at least 15 minutes before turning it back on.

 

[AshleyL]

Unless if your Growatt model is TL-XH with battery port, it will never pull power from utility.

TL-X model can only inject power.

 

[LydMekk]

Growatt...

 

[ericatb8a]

Unless if your Growatt model is TL-XH with battery port, it will never pull power from utility.

TL-X model can only inject power.

There might be a mix-up where the SunGoldPower AIO system incorrectly feeds power to the idle Growatt inverter, which then reflects it back, leading to about 5.5 kW surging into my electrical load. This created a dangerous situation.

 

[goldserve]

I'm wondering how two inverters can be connected to critical loads panel if they are not synced to phase. Only one inverter can be connected to critical loads unless you have inverters that can do load sharing and master/slave, parallel configuration.

 

[ericatb8a]

I'm wondering how two inverters can be connected to critical loads panel if they are not synced to phase. Only one inverter can be connected to critical loads unless you have inverters that can do load sharing and master/slave, parallel configuration.

The SunGoldPower AIO is an offgrid inverter with no AC coupling capability. The Growatt MIN 5000TL-X is a grid tied inverter. Thus the Growatt is synced to the SunGoldPower.

 

[goldserve]

I wonder what will happen when the grid tied inverter is pushing max power but your critical loads can’t use up the power. The theory is that the output voltage will keep on rising and hopefully something will shutoff before permanent damage?

 

[1201]

The growatt is not the problem. You need to describe your setup in more detail @ericatb8a

 

[1201]

The SunGoldPower AIO is an offgrid inverter with no AC coupling capability. The Growatt MIN 5000TL-X is a grid tied inverter. Thus the Growatt is synced to the SunGoldPower.

So if there is no ac coupling capability, and your sungold is not able to control the output of the growatt, the excess power has to go somewhere.

 

[AshleyL]

The SunGoldPower AIO is an offgrid inverter with no AC coupling capability. The Growatt MIN 5000TL-X is a grid tied inverter. Thus the Growatt is synced to the SunGoldPower.

Exactly, I wonder if he has the smart meter (or CT) installed for the zero export? Otherwise, the TL-X will inject all available solar power into his "internal grid". Then again, if he did have one, where do he put the smart meter / CT at?

His original interpretation of Growatt drawing power from grid/utility is totally wrong in the first place. TL-X model doesn't have the necessary circuit board in it to drain power from the utility/grid.

 

[AshleyL]

There might be a mix-up where the SunGoldPower AIO system incorrectly feeds power to the idle Growatt inverter, which then reflects it back, leading to about 5.5 kW surging into my electrical load. This created a dangerous situation.

Errr......what?

 

[ericatb8a]

I wonder what will happen when the grid tied inverter is pushing max power but your critical loads can’t use up the power. The theory is that the output voltage will keep on rising and hopefully something will shutoff before permanent damage?

Apparently the voltage did not rise enough for my AIO inverter to shutdown.

 

[ericatb8a]

The growatt is not the problem. You need to describe your setup in more detail @ericatb8a

 

[ericatb8a]

Exactly, I wonder if he has the smart meter (or CT) installed for the zero export? Otherwise, the TL-X will inject all available solar power into his "internal grid". Then again, if he did have one, where do he put the smart meter / CT at?

His original interpretation of Growatt drawing power from grid/utility is totally wrong in the first place. TL-X model doesn't have the necessary circuit board in it to drain power from the utility/grid.

No CT installed yet. Please note the TL-X input (i.e. solar) was disconnected. It was also early morning and there is minimal power from the solar array.

Good to know that there is no way Growatt to draw power from the Utility. Then what happened? Is the AIO inverter somehow confused the Growatt as a load and pumping power toward it? And the Growatt reflects the power back?

 

[ericatb8a]

Errr......what?

Exactly and this is a crazy theory. But my power did surge (hard evidence was the burning smell and the power graph).

 

[goldserve]

Hard to explain why growatt would even log power when there is NO solar panels. Do you have an idea of what created the smell and heat? Is Growatt damaged or is the SGP inverter now damaged. Check all your terminal for signs of high heat (changed color).

 

[AshleyL]

Hard to explain why growatt would even log power when there is NO solar panels. Do you have an idea of what created the smell and heat? Is Growatt damaged or is the SGP inverter now damaged. Check all your terminal for signs of high heat (changed color).

The only way this can happen is......your solar panel breaker isn't functioning?

Since your grid is a "closed loop" and there is no smart meter/CT installed (plus no zero export), when the sun rise up....it kept on injecting the power into your "closed loop grid"? Those power gotta go somewhere....... example, in utility power station, the excess is dumped to ground.

If you keep a log of the Growatt inverter solar power production, can you check the log? Does Growatt inverter receive any power from the solar panel? Yes, I know you said it is not turned on, but the possibility of faulty solar breaker is there......

 

[1201]

The growatt cannot pull power from the grid and in this scenario cannot output any power since there is no battery or solar connected.


What's the growatt connected for?

 

[Koyaanisqatsi]

Exactly and this is a crazy theory. But my power did surge (hard evidence was the burning smell and the power graph).

All bets are off when you smell smoke, and it no longer matters what capabilities each device has or how it was wired. Best thing you can do now is to start pulling components out and testing them, starting with the Growatt. My guess is your Growatt had a failure of some kind and is no longer doing what you think. Watch to see if the rest of your system changes behavior when the Growatt is disconnected. That could tell you a lot about what happened.

I suspect that the Growatt was added with the intention of eventually connecting PV or battery to it. But without at least one of those, it might have been put into a scenario it can't support. Basically, connected to grid power with no energy source for it to provide any output means it was just a load, and may have failed because of that. Another possibility is it just failed on random chance.

 

[1201]

All bets are off when you smell smoke, and it no longer matters what capabilities each device has or how it was wired. Best thing you can do now is to start pulling components out and testing them, starting with the Growatt. My guess is your Growatt had a failure of some kind and is no longer doing what you think. Watch to see if the rest of your system changes behavior when the Growatt is disconnected. That could tell you a lot about what happened.

I suspect that the Growatt was added with the intention of eventually connecting PV or battery to it. But without at least one of those, it might have been put into a scenario it can't support. Basically, connected to grid power with no energy source for it to provide any output means it was just a load, and may have failed because of that. Another possibility is it just failed on random chance.

if you connect a grid tie inverter without pv to the grid, it syncs to the grid and waits for pv input.

I suspect that the op has pv connected to the growatt and has chosen to not disclose that

 

[ericatb8a]

Hard to explain why growatt would even log power when there is NO solar panels. Do you have an idea of what created the smell and heat? Is Growatt damaged or is the SGP inverter now damaged. Check all your terminal for signs of high heat (changed color).

Growatt log did not show power

All bets are off when you smell smoke, and it no longer matters what capabilities each device has or how it was wired. Best thing you can do now is to start pulling components out and testing them, starting with the Growatt. My guess is your Growatt had a failure of some kind and is no longer doing what you think. Watch to see if the rest of your system changes behavior when the Growatt is disconnected. That could tell you a lot about what happened.

I suspect that the Growatt was added with the intention of eventually connecting PV or battery to it. But without at least one of those, it might have been put into a scenario it can't support. Basically, connected to grid power with no energy source for it to provide any output means it was just a load, and may have failed because of that. Another possibility is it just failed on random chance.

Update: I've fully disconnected the Growatt, leaving the SunGoldPower AIO working by itself. The AIO worked without issues for the remainder of Sunday and all of Monday. Yet, come Tuesday morning, the plastic burning smell returns again. It's puzzling because this setup worked flawlessly for over a month before the recent incident with the Growatt. Since the current draw seems normal, I allowed the system to operate for an additional hour after turning off heavy loads, but the smell continued.

I took out the AIO and reverted to direct utility power. The burning smell is now gone. Here is a recap:

1. Original Configuration: The SunGoldPower AIO operated off-grid successfully for over a month.
2. Early Sunday: Added the Growatt to test grid-tie capability with a small 200W load from solar due to the early hour.
3. Solar array was disconnected from Growatt; however, the AC connection remained.

4. Power Surge: The load suddenly increased to 5.5kW from under 1.0kW as reported by the AIO.
5. After half an hour away to showering, I notice a strong burning smell immediately after exiting my bedroom.
6. Turned off the system and removed the Growatt.

7. Post-Growatt: The AIO seemed fine for the rest of Sunday and all of Monday.
8. Smell Returns: Early Monday, the burning smell returned with the system drawing only about 1 kW, typical for my usage. I turned off heavy consumers, monitored power levels for another hour, and the smell persisted.
9. Current configuration: I disconnected the AIO and switched back to utility power, after which the burning smell ceased.

 

[goldserve]

Growatt is probably fine but I would not use the SGP anymore without some thermal imaging camera to see where the heat is coming from. Without extensive knowledge of electronics, I would be hesitant to use the SGP anymore just for the piece of mind.

 

[ericatb8a]

Growatt is probably fine but I would not use the SGP anymore without some thermal imaging camera to see where the heat is coming from. Without extensive knowledge of electronics, I would be hesitant to use the SGP anymore just for the piece of mind.

I am offlining the SGP.

 

[Koyaanisqatsi]

I'm suspect of all of it. I've seen power issues take out a lot more hardware than anyone expects a few times. If the SGP isn't working properly, there are a lot of ways that could have happened. It could have failed on its own or been killed by a failure in the Growatt.

Smells can be deceiving on new equipment. What is the possibility that the SGP is running hotter than usual due to higher load and thus smelling badly, but otherwise fine? Monday was toasty hot in CA. It might not have any failure, if the power surge from the Growatt was not beyond its specs.

 

[ericatb8a]

if you connect a grid tie inverter without pv to the grid, it syncs to the grid and waits for pv input.

I suspect that the op has pv connected to the growatt and has chosen to not disclose that

PV is positively not connected. Otherwise there is no puzzle. Anyway the update is that the electrical burning smells happened again on Tuesday morning (1st time was Sunday morning). Growatt was not even connected in anyway.