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Safe Grid Use of the 5000ES and transformer

Bud Martin said:
I am talking about the internal circuit beaker inside the unit @16:18 in the video, it should be dual gang breaker not single breaker to protect L1, the breaker is locate at the bottom left of the unit in the video.
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The factory one, yes, I see now.
 
It would take a lot to read and follow all this thread.

To SUM it up from MY understanding.

1. You need to make sure the ground is NOT bonded inside the Growatt 5000ES inverters. This is the grounding screw issue. If purchased from Signature Solar you should be good to go, anywhere else, all bets are off. Buyer Beware.

2. These inverters are generally used with an Autotransformer which adds some additional safety concerns. If the autotransformer fails, overloads, or is disconnected while power is still being supplied by inverter(s), 240v will be applied to one leg of your 120v circuits, potentially frying a lot of stuff. The fix to this is make sure power is disconnected if autotransformer is ever disconnected or fails. There is more than one way to fix this, but generally you need a breaker setup that disconnects the loads or inverters output if the Autotransformer is ever disconnected from the panel or tripped.

3. Grid Pass Thru with autotransformer Re-circulating current. This is an issue that doesn't have a good solution with the Signature Solar or Solar Edge autotransformers. The issue is the autotransformer is going to try to balance the utility grid loads all the way to the utility transformer "not just inverter loads" when the inverter is in grid pass thru mode. The worst part of this is, it's going to try to do it though the bonded shared ground, since the Growatt 5000ES does NOT pass neutral thru the inverter.

I still stand by my statement: I do NOT recommend this setup for Grid connected installations. Offgrid can be made safe IF the installer knows what they are doing.
 
Mr-Sandman said:
It would take a lot to read and follow all this thread.

To SUM it up from MY understanding.

1. You need to make sure the ground is NOT bonded inside the Growatt 5000ES inverters. This is the grounding screw issue. If purchased from Signature Solar you should be good to go, anywhere else, all bets are off. Buyer Beware.

2. These inverters are generally used with an Autotransformer which adds some additional safety concerns. If the autotransformer fails, overloads, or is disconnected while power is still being supplied by inverter(s), 240v will be applied to one leg of your 120v circuits, potentially frying a lot of stuff. The fix to this is make sure power is disconnected if autotransformer is ever disconnected or fails. There is more than one way to fix this, but generally you need a breaker setup that disconnects the loads or inverters output if the Autotransformer is ever disconnected from the panel or tripped.

3. Grid Pass Thru with autotransformer Re-circulating current. This is an issue that doesn't have a good solution with the Signature Solar or Solar Edge autotransformers. The issue is the autotransformer is going to try to balance the utility grid loads all the way to the utility transformer "not just inverter loads" when the inverter is in grid pass thru mode. The worst part of this is, it's going to try to do it though the bonded shared ground, since the Growatt 5000ES does NOT pass neutral thru the inverter.
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Good summary and my understanding as well.
Mr-Sandman said:
I still stand by my statement: I do NOT recommend this setup for Grid connected installations. Offgrid can be made safe IF the installer knows what they are doing.
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I’m also uncomfortable with the single-phase-240VAC-grid-toed-with-Autotransformer architecture to offset consumption because of unease about the idea of an Autotransformer balancing non-critical loads in parallel with the transformer on the utility pole (using Growatt’s architecture or any of the number of similar approaches by other vendors.

Is there a recommended architecture considered ‘best’ for this use-case?

A pair of grid-toed 120VAC inverters seems like it may be a better approach to grid-tied consumption offset - is there anyone making such a solution that will push power to the grid using an energy meter or CT sensors?

Backup power is a different animal and not a priority for me - I’m just looking for a cost-effective solution to capture solar power into a battery and offset consumption both during the day as well as after the sun has gone down…
 
fafrd said:
Is there a recommended architecture considered ‘best’ for this use-case?
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Yes, there's several. My opinion if you are going to be grid interactive, you should look at UL certified/listed equipment.

I personally use a Schneider XW Pro 6848, it is completely grid interactive. You can set it up to self consumption, sell to grid, grid backup, load shaving, time of use, AC Coupling with grid/battery, and more. It's a 240/120 split phase unit "NO autotransformers needed", has Neutral pass thru and built in transfer switches.

I'm sure there's some cheaper china options, but I will not comment on those, since I have no personal experience with them.
 
You people are unbelievable. ArkRob asked to see a video of Grid Pass through. Whether it has an auto transformer or batteries is pointless. Doesn't matter to you. You're going to find something to bitch about. Here's a couple of more. I doubt these will make you happy either. This why I don't participate more. All the bullshit coming from the no-it-alls.

Here you go. Nit pick these!!!!!


 
Brightside said:
I have these units, and have installed these units from SS. Nice unit, works great, no issues. These were received last year, 2021, in Nov.
Yes, the Labeling is incorrect on the Nameplate and the N labeled connections, but SS clearly states that N is L when purchasing. Yes, the labeling does need to be changed, as, everyone is confused and there is no way to tell the difference between a ES and US unit, as they are are labeled ES.
Attached are pictures of the unit showing the N and G are not tied. Pictures also show the PCB has been modified as SS claims, as the ground screw people remove on other sellers units is still in place and grounded. This means that the Neutral trace has been changed to floating line on the PCB(I haven't looked any farther at this point, just wanted to put this put there to satisfy curious minds)
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Can you read the spec of that AC input thermal circuit breaker for L (L1) on the bottom left of the unit? Thanks.
 
OpenNRG said:
You people are unbelievable. ArkRob asked to see a video of Grid Pass through. Whether it has an auto transformer or batteries is pointless. Doesn't matter to you. You're going to find something to bitch about. Here's a couple of more. I doubt these will make you happy either. This why I don't participate more. All the bullshit coming from the no-it-alls.

Here you go. Nit pick these!!!!!


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No sir, grid pass WITH autotransformer is EXACTLY the point. That is the safety issue me and others have outlined in many post. There's no argument that it can be done and works, it's the safety issue it creates while in Grid Pass Thru with that configuration that is the issue.
 
Mr-Sandman said:
No sir, grid pass WITH autotransformer is EXACTLY the point. That is the safety issue me and others have outlined in many post. There's no argument that it can be done and works, it's the safety issue it creates while in Grid Pass Thru with that configuration that is the issue.
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OK, I stand corrected. Maybe the next two videos cover it. That's all I have.
 
Mr-Sandman said:
Yes, there's several. My opinion if you are going to be grid interactive, you should look at UL certified/listed equipment.

I personally use a Schneider XW Pro 6848, it is completely grid interactive. You can set it up to self consumption, sell to grid, grid backup, load shaving, time of use, AC Coupling with grid/battery, and more. It's a 240/120 split phase unit "NO autotransformers needed", has Neutral pass thru and built in transfer switches.

I'm sure there's some cheaper china options, but I will not comment on those, since I have no personal experience with them.
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Yeah, I’ve been looking at the XW-Pro and it seems like a pretty solid solution, but I have a question:

The XW-Pro is a low-frequency inverter using an internal transformer to generate split-phase output, is it not?

If so, how are these concerns regarding circulating currents when a transformer connected to L1, L2 and N is connected in parallel to the transformer on the utility pole any different?
 
fafrd said:
Yeah, I’ve been looking at the XW-Pro and it seems like a pretty solid solution, but I have a question:

The XW-Pro is a low-frequency inverter using an internal transformer to generate split-phase output, is it not?

If so, how are these concerns regarding circulating currents when a transformer connected to L1, L2 and N is connected in parallel to the transformer on the utility pole any different?
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Well I don't know how the XW does all its magic, but the big difference between a 240v none split phase inverter with external autotransformer and the XW is the XW has complete control of its internal transformer, it decides when it's connected and used vs utility, etc.
 
I would think when it is in utility mode the internal transfer switch will disconnect the L1, L2 of the inverter xformer output so they will not be connected to the utility in utility mode.
BTW, I would not think that the LF inverter with true split phase output will be using Auto transformer (is not the same as isolation transformer), it will use isolation transformer which the Primary winding is driven by MOFET'S that get the DC Voltage from the battery and step that Voltage up to 240V by the secondary winding with center tap.
 
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That makes sense.. I can tell the XW configures itself differently depending on what's it's doing. 1 mode will be Inverting off battery "no grid" its using it's split phase transformer in this mode. 2 mode would be grid interactive, it is not using it in this mode, it's acting more like a grid tie inverter injecting 240v power onto the grid connection. 3 AC Coupling, has a couple different modes, based on presence of grid or not. 4 Charging mode.
 
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Mr-Sandman said:
Well I don't know how the XW does all its magic, but the big difference between a 240v none split phase inverter with external autotransformer and the XW is the XW has complete control of its internal transformer, it decides when it's connected and used vs utility, etc.
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The point is not whether the XW has full control of its transformer or not.

The point is that anytime you connect a low-frequency (with transformer) inverter to the grid, you have the ‘2 transformers in parallel’ issue.

When passaging-through only, so either L1, L2 and N all pass-through transfer switches and the inverter and transformer are bypassed or at least the transformer is so that the inverter is only generating single-phase 240VAC, there is no issue.

If operating in off-grid backup mode so that the transformer is generating L1, L2 and N from the inverters L1 and L2 with no connection to the transformer on the utility pole, there is no issue.

But if the internal transformer is connected while the inverter is generating power to offset non-critical loads, the same issue must exist…
 
Mr-Sandman said:
That makes sense.. I can tell the XW configures itself differently depending on what's it's doing. 1 mode will be Inverting off battery "no grid" its using it's split phase transformer in this mode. 2 mode would be grid interactive, it is not using it in this mode, it's acting more like a grid tie inverter injecting 240v power onto the grid connection. 3 AC Coupling, has a couple different modes, based on presence of grid or not. 4 Charging mode.
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If the transformer is not connected when tied to grid, they would avoid a similar issue…
 
That's what I'm saying when I say the XW has full control of the transformer. It decides when gird/transformer is connected. I know there's some clicks internally when it switches from grid interactive to off grid. It reconfigures itself for whatever mode it needs. It likely has a relay that switch L1/L2 output between grid or transformer output, they are never connected together, but Neutral passes thru... Just guessing here, I'll state again, I don't know how the XW does all it's magic, but it is UL certified AND listed. So someone smarter than me verified it's good to go on the US grid.
 
OpenNRG said:
Here you go. Nit pick these!!!!!
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When I see someone post a video here that they claim shows how safe a unit is yet the video contains unsafe practices in other parts of the system, I quit watching. I don't consider it credible and I'm not wasting my time with it.

After a period of time, one learns to avoid even clicking on videos by those who promote videos with unsafe practices contained within.
 
Zwy said:
When I see someone post a video here that they claim shows how safe a unit is yet the video contains unsafe practices in other parts of the system, I quit watching. I don't consider it credible and I'm not wasting my time with it.

After a period of time, one learns to avoid even clicking on videos by those who promote videos with unsafe practices contained within.
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WHERE DID I CLAIM OR PROMOTE ANYTHING?
 
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