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Growatt 3000 LVM possible inverter issues

What is battery voltage doing during this flickering - since it doesn't happen on Grid, recheck all wire connections and Breakers input and output, other than that - inverter. Have seen one of these go bad under load. 1618871288718.png
 
"I have a Growatt 3000 LVM 24V inverter. I have been so happy with it until recently." So the problem just started? It was running with the two fridge in the past with the same exact setup fine without any flickering until now?
 
We have been checking and rechecking all of the wiring for a couple of weeks to ensure that it is not something we did. Battery voltages are stable with sun at the float when charged. After sundown it stays stable at 26.5V under no load. When both fridges are running the voltage drops to 26.2V then rebounds back to 26.5V after they shut down. I usually have 26.2V at sun up. I have checked these voltages everyday and have multimeters laying at both fridge outlets. I also have Kill-A Watts plugged in to observe the fridge outlets.

We have checked voltages at every connection leaving the Growatt to the disconnect, to the breakers, at the outlets. When the fridges run together, the voltages fluctuate and the Kill-A-Watts show the frequency bouncing around a little. But when the fridges are not running, all is stable. I have test the inverter under heavy loads with two heat guns pulling to capacity, and the voltages are stable. It is only when two fridge compressors are running.

Could they be feeding noise back and causing this?
 
We have been checking and rechecking all of the wiring for a couple of weeks to ensure that it is not something we did. Battery voltages are stable with sun at the float when charged. After sundown it stays stable at 26.5V under no load. When both fridges are running the voltage drops to 26.2V then rebounds back to 26.5V after they shut down. I usually have 26.2V at sun up. I have checked these voltages everyday and have multimeters laying at both fridge outlets. I also have Kill-A Watts plugged in to observe the fridge outlets.

We have checked voltages at every connection leaving the Growatt to the disconnect, to the breakers, at the outlets. When the fridges run together, the voltages fluctuate and the Kill-A-Watts show the frequency bouncing around a little. But when the fridges are not running, all is stable. I have test the inverter under heavy loads with two heat guns pulling to capacity, and the voltages are stable. It is only when two fridge compressors are running.

Could they be feeding noise back and causing this?
Good question, looks like @Bud Martin is having the same issue, my Growatt has a 240v 75lbs transformer so without an Oscilloscope or others suggestions, I could not tell you. Mabe someone else can chime in.
 
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"I have a Growatt 3000 LVM 24V inverter. I have been so happy with it until recently." So the problem just started? It was running with the two fridge in the past with the same exact setup fine without any flickering until now?
The flickering was there from day one, but I never really noticed as I wasn't looking for it. The flickering starts out very softly, then gets more intense as the compressors run longer. It only happens when both are running at the same time, and you have to open the fridge at that exact time. Once I realized this could be a problem, I started looking for it, and opened the fridge every time I heard the compressor run, then you start seeing it more often and watching it longer to see it intensify. We have been looking for the problem for weeks now.

I was very happy with it as we thought it was something that we did. I didn't think that it could be the Growatt until recently.
 
You do have 3 prong plugs on each freezer and receptacles are 3 wire also - right, not using extension cords either?
 
Yes, the system and wiring are actually done to code, and recently passed inspection. No extension cables in use.

I use extension cords when plugging in my refrigerators to my portable “solar generators”. No flickering with that set up. I have had both fridges plugged into a Jackery 1000. Bluetti EB 2400 and my own self built portable units. No flickering with long extension cords. That is why we thought it was something we did wrong.
 
Last night, I hard wired my Giandel 2200W inverter to the wiring we installed for the Growatt. We ran one fridge and an upright freezer all night long and all went well with no flickering or issues. I connected the Growatt back up early this morning, fired up the fridge and freezer again, and once they both kicked on, the flickering was back. I am now satisfied that our wiring is OK.

After all of this, I feel there are no other options other than to return the Growatt (if possible). Thanks everyone!
 
A bigger inverter would be a jump to 48V. That would require a lot of $ for more batteries to meet the 400Ah (minimum suggested) for the 48V Growatt. I am thinking about going with a Victron Multiplus 24/3000 120V. Found one on sale for $1095. I have read that it can be configured with "solar as priority", and draw from the grid when the batteries reach a low voltage set point. I already have a VE 150/45 SCC. It all depends on what happens with the Growatt. I will post after I know. Thanks again Joe!
 
I am wondering if it wouldn't be easier to just only run one fridge off the Growatt. Move the most efficient unit back to grid?
 
I am wondering if it wouldn't be easier to just only run one fridge off the Growatt. Move the most efficient unit back to grid?
That would be easier, but the idea is to have four very important things running in the event of an outage. We have frequent outages, and in winter they are quite long sometimes. We are often gone on weekends during the summer. So we need to have the following running when we are not home, and an outage occurs. We do not want a flooded basement, and spoiled food.

2 fridge/freezers
1 upright freezer when being used
2 sump pumps

We have other things running on the solar which is a bonus, along with a smaller electric bill. We had plans to add an additional Growatt to cover our furnace in the winter. That is now out for me.
 
That would be easier, but the idea is to have four very important things running in the event of an outage. We have frequent outages, and in winter they are quite long sometimes. We are often gone on weekends during the summer. So we need to have the following running when we are not home, and an outage occurs. We do not want a flooded basement, and spoiled food.

2 fridge/freezers
1 upright freezer when being used
2 sump pumps

We have other things running on the solar which is a bonus, along with a smaller electric bill. We had plans to add an additional Growatt to cover our furnace in the winter. That is now out for me.

Here is my suggestion as I am in a similar situation with wanting the freezers protected in case of outages. Move the GroWatt to the furnace. Buy a Tier 1 unit to user on the freezers, etc. Samlex or Victron. Others are better at knowing the Tier one units. I need to do this as well - then the GroWatt becomes the backup. One is none, two is one.
 
@Repro...I just saw this thread. Having a similar issue...

- I have the Growatt 3000TL-LVM-48P

- Among other loads, I had it running a full size Whirlpool side-by-side fridge on a dedicated 20A circuit. I thought it was running fine for several days, but one day wife said lights inside were flickering on both sides (fridge/freezer).

At the moment the system is disconnected. I was planning to troubleshoot the issue in the coming days. I put the fridge back on its original utility grid circuit in the meantime. Working fine.

Like @smoothJoey was mentioning (on the first page of this thread), I was skeptical the earth ground thing would solve the problem. I think he was onto something where he mentioned the neutral-ground bond causing ground loops.
This is very likely nothing to do with the rods in the ground.
Its very likely about having multiple bonds between neutral and ground.
You can isolate your panels for a test.
I guess I'll just move along.

As I understand it, the Growatt will unbond neutral and ground when powered by AC input, but will automatically bond ground-neutral when running from battery/solar, after the ATS makes the transfer. Could that be creating a problematic ground loop? This would explain why a different inverter you hooked up does not cause the same issue as the Growatt? Can the Growatt be set to NOT do its N-G bond thing? I believe there may be a setting for this (#24 possibly?).

It seems SJ left the thread, but maybe he will come back to offer ideas.
 
@Repro...I just saw this thread. Having a similar issue...

- I have the Growatt 3000TL-LVM-48P

- Among other loads, I had it running a full size Whirlpool side-by-side fridge on a dedicated 20A circuit. I thought it was running fine for several days, but one day wife said lights inside were flickering on both sides (fridge/freezer).

At the moment the system is disconnected. I was planning to troubleshoot the issue in the coming days. I put the fridge back on its original utility grid circuit in the meantime. Working fine.

Like @smoothJoey was mentioning (on the first page of this thread), I was skeptical the earth ground thing would solve the problem. I think he was onto something where he mentioned the neutral-ground bond causing ground loops.


As I understand it, the Growatt will unbond neutral and ground when powered by AC input, but will automatically bond ground-neutral when running from battery/solar, after the ATS makes the transfer. Could that be creating a problematic ground loop? This would explain why a different inverter you hooked up does not cause the same issue as the Growatt? Can the Growatt be set to NOT do its N-G bond thing? I believe there may be a setting for this (#24 possibly?).

It seems SJ left the thread, but maybe he will come back to offer ideas.
I looked at #24, and it is only available when connecting Growatt's in parallel (expansion). I am not sure that any parameters above #22 can be accessed. Thanks!
 
Here is my suggestion as I am in a similar situation with wanting the freezers protected in case of outages. Move the GroWatt to the furnace. Buy a Tier 1 unit to user on the freezers, etc. Samlex or Victron. Others are better at knowing the Tier one units. I need to do this as well - then the GroWatt becomes the backup. One is none, two is one.
I don't know what you mean by Tier 1? I know what Tier 1 solar panels are, but that will not help me. Can you elaborate please?
 
I just talked to the dealer, and he wants to send me a replacement unit to see if that solves the problem. I have my Giandel 2200W hard wired into my system right now, and I will leave it until the replacement unit arrives. The dealer and I are both worried that this problem may be a feature and not go away with a replacement unit. We will find out. I hope so bad as I love this thing. It was so easy to install, and barring the issue I have, it just works. Set it and forget it.
 
So the issue I have with your setup is that each big ticket item is supposed to be on its own 20amp circuit. Where it get's sticky is that the output of the Growatt is basically a single 20amp circuit, so although you may be running a breaker box with individual circuits to code and you can piggy back a ton of stuff onto it because the wattage is there, you really shouldn't be. I think I would opt for a second unit maybe paralleled to give you split phase with a fridge on each, but I understand your frustration about spending more money on a solution that may or may not work.
 
Hmm sadly with "big ticket items" inrush current really is an issue and its hard to find any current meters under $100 that can do inrush readings.
kil-a-watts and normal multimeters are useless for such measurements. Anything with a motor is a sneaky little transient current eater, and you have several at the table waiting to eat.
There is one meter that shows up under $100 when you search for "cheap inrush current measurement"...but the comments are not that great for the mastech hehe
 
The system is designed to handle a few items that don't even push this to half of its capacity. The chart you see is a typical day with two fridges and two sump pumps running. The wash machine (1-2 times a week) pushes it to 1200W total load in short cycles. The normal load is around 550W. I also have two battery tenders plugged in that probably wouldn't even show a draw. I can't believe my problem stems from big ticket items causing an inrush of current. I really don't want to fork out money for the expansion when one doesn't do the job correctly. To me, that is like patching the problem and it still being there.

Right now, I have a 12V, 420Ah portable system with a Giandel 2200W inverter I built for my RV, hard wired into the system we installed where the Growatt was. Everything is running fine since last night with no flickering or compressor issues. It is only my opinion that the Growatt is either defective, or that model has problems with running more than one inductive motor at one time due to noise feedback.

Can anyone recommend a low cost oscilloscope with decent quality? I found the Multimeter-oscilloscopes online, but I am skeptical they are any good.
 

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