Safe Grid Use of the 5000ES and transformer

[OpenNRG]

The SS Growatt 5000ES has lots of features that are useful for DIY solar/battery/grid sharing that some of us want. You can run up to 430 volts of solar into it at up to 18 amps so each additional 5000ES that you add gives you everything you need to add another 6kW of solar to your system. (e.g. 6KW west facing roof, 6kW east facing roof, 6kW south facing roof. You can even run the inverters off solar alone or solar with grid sharing without batteries for self consumption. As for the "European Model", in the settings you can select 240 volts and 60 Hz. Signature Solar already addressed the AT issue by working with the Growatt team to have the NG bond removed before promoting it with an AT for split phase in the North American market. They are addressing the concerns that some have brought up. The one that I am now running with an AT is working flawlessly and there are no current flowing through the ground bus-bar to the ground rod. I will add another one in the spring when I increase my new solar to 12kW. My opinion is that the 5000 people/units who have bought these 240 volt 5000ES(US version from SS) did so because thy have specific requirements that these can meet for a low price. D. Pos likes them because they work for him. Two of them with one AT gives him full use of his solar capacity and has the added benefit of increasing the surge capacity, more like a low frequency inverter. I also have a 12kW split phase Aims inverter with a grid pass through and the ability to absorb huge inrush currents but its now priced at 4500$ US. When I'm done I will have spent 3 X $900 GW 5000ES/US + 1 X $350 (AT) or $3050 for 15kW of 240/split phase self consumption solar power.
So now you know why someone would choose the 5000ES US product over your LV6048. Two of those for the same price as 3 of the 5000ES and an AT would only give you 12kW without the added headroom for large inrush currents.
It would make more sense to say that you don't have a requirement for the 5000ES in your application than saying "What I don't understand, is why anyone would buy the ES and mess with these auto transformers at all". How do you think low frequency inverters make 240/120 split phase in the first place for the NA market? They just use a transformer with a center tap (an internal AT).

Been thinking of posting the same comment. Well done.
You forgot to mention Grid Sharing, another plus for those without batteries or when your batteries are low but the sun is out.

 

[Bud Martin]

PeteB: So if you look at your unit, did they remove the standoff where the PCB to chassis bonding screw is without removing the standoff?

 

[Zwy]

#1 did You say it in your not to buy this unit video?

Will never did the SPF 5000ES that I can recall. He did a video on a 48V SPF3000 TL here that looks similar to the 5000 ES.

And he announced the SPF 3000TL in this video, around 8 min.

This is the infamous Poz video:

#2 You can buy the Transformer separately or in a package

You can buy an isolation transformer, just not from SS.

#3 come on man, don’t backtracking now. I watch you videos over and over, there was no indication this was a problem. I purchased three of them and will have a master electrician install them, dam I trusted you and Poz now what are we suppose to do.

I'd like to see a link where Will did show a 5000ES.

My suggestion is to contact the company you bought from and return the product.

 

[Bud Martin]

Exactly. I think most of this brouhaha is due to opinions and not fact based. I'm confident that Signature Solar are doing their due diligence as evidenced by the drawing they issued and the statement that their testing and analysis of the manufacturer ground screw removal solution. It may come to light that Growatt removed the ground-screw standoff, or have insulated this under the board. It may also be changed in future US versions of this inverter. Both good resolutions in my opinion. I would even consider using a syringe to pump some silicone into the ground screw hole and between it and the case if necessary. My plan is to first transfer all the parasitic and base load circuits of my house to the Growatt 5000ES (with AT) and then add circuits until I max out my self consumption. I have the inverter set to SBU so when I run out of daily solar it consumes the 14kWh battery and then switches to utility. My time of use rates are lowest overnight so I may even charge the battery to time shift some of my grid usage to the cheaper rate in winter. All of these things are available with the 5000ES and I can monitor everything with their app. In the past I have used Tristar TS60MPPT charge controllers for my solar but they require more complex wiring for short strings because they're only a 150 volt max.

That is one of my main concern, removing just screw without removing the standoff or put insulation sheet under the PCB is not acceptable, the clearance space between PCB and standoff may be only 10mil (0.01"), it can easily have arc over in damp condition/contamination. i can easily put Scotch tape to insulate between PCB and standoff or chassis in the products I design, the customer can Ohm it out and it will show no connection so he thinks it is safe but that Scotch tape will never pass safety test.
I am still waiting for pictures and test result from SS to be posted. I also wonder why the test are being done now instead of being done in the beginning of the first sample unit SS received from GroWatt.
Post #130:

What kind of shorts circuit are you going to do? L1, L2 shorted the grounded chassis (bonded and un-bonded between two ground rods)? Shorted to the un-grounded chassis? etc. Voltage reading and leakage current test between chassis and ground?
Are we still going to see the pictures of the PCB where the screw is removed, and pictures of the bottom side of the PCB? Pictures of the chassis so we can see if the standoff is removed or not?
BTW, live wire shorted to the chassis is one of the test I perform in the lab to verify that the breaker will trip and no wires will burn up, it is part of the UL test.

SS: All of this. We are doing tons, will have videos, pictures and more. Just a lot to do and we will be posting them in the future.

 

[Tony Scott]

Can you show the Link to Will's video?

Post the video here, I've never used this unit in my life. I'm not backtracking anything. Post the video here.

It was the 3000 not the 5000

 

[Tony Scott]

Post the video here, I've never used this unit in my life. I'm not backtracking anything. Post the video here.

I renoved the post it was the 3000 not the 5000

 

[Bud Martin]

It was the 3000 not the 5000

Well, if you look at the details and the spec of the unit in the video, it is not 3000 ES Euro unit, the unit in the Video is 120V.
Spec of the unit in the video: Model SPF-3000TL LVM (48V SPF 3kW LVM Off Grid 120V Inverter with Solar Charge Controller), nothing to do with SPF-3000 ES which is 230VAC unit.

Growatt 3kW Stackable Off-Grid Inverter | SPF 3000TL LVM-48P

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

www.signaturesolar.com

 

[Will Prowse]

My understanding is that they did do testing when they partnered with Growatt and they believed that the issue was resolved by Growatt because of that testing. I have not seen any evidence that there has been any failures of this inverter due to the issue that is being discussed. Having an electrical engineer say that he does not like the bond screw removal solution is not evidence. When I test the terminals and case with a fluke I don't get any leakage current with everything running at a high% load so at this point I'm still comfortable with using the inverter and the AT with the SS recommended wiring and bypass switch. If someone has photos of a 5000ES with a burned board at the bond point I would like to see photos of it.
You don't always know what you don't know. Discovering the small flaws and resolving them are what lead to the innovation that makes products better.

Myself and many others on this forum can think this out and make this inverter work safely. But that is not the point.

The issue is that they are selling an inverter that has a very high potential for safety issues when used in a location that it is not designed for. Especially by beginners. Then they conjured up a schematic that clearly has problems.

That is fantastic that you have a fluke meter, and that you are doing your own due diligence, but many others are not. Many who have purchased this model do not understand the term "bonding" or "grounding".

These are not "small flaws". This inverter is designed for safe use with the European grid, and not the North American grid. Sure, you can eventually make it work, but there are still some risks. Hightechlab mentioned a valid risk of losing the neutral and how beginners may wire it to cause this issue.

I am glad that you have managed to get yours to work, but everyone here is thinking about the safety of others. Just because I can personally make something work does not mean I am going to post schematics for others to copy. I took down many videos that showed people how to run various batteries without a bms. I managed to make it work, but it took years of catching lipoly cells on fire to figure out what I was doing. It was my responsibility to remove those videos and focus on LiFePO4, which was a much safer option for beginners. I think it is everyone's responsibility to call out obvious safety concerns when it comes to solar power systems.

 

[Will Prowse]

My understanding is that they did do testing when they partnered with Growatt and they believed that the issue was resolved by Growatt because of that testing. I have not seen any evidence that there has been any failures of this inverter due to the issue that is being discussed. Having an electrical engineer say that he does not like the bond screw removal solution is not evidence. When I test the terminals and case with a fluke I don't get any leakage current with everything running at a high% load so at this point I'm still comfortable with using the inverter and the AT with the SS recommended wiring and bypass switch. If someone has photos of a 5000ES with a burned board at the bond point I would like to see photos of it.
You don't always know what you don't know. Discovering the small flaws and resolving them are what lead to the innovation that makes products better.

No, you will overload it, then it will shut itself down. The main problem I see is losing the autotransformer neutral (let's say they add a circuit breaker and turn it off, or fail to create a proper termination), which causes 240V to be applied to 120V loads in series. You can easily cause a fire in this situation. Or if someone uses north american ground potential on the grounding conductor input, and they are using an inverter not supplied by signature solar (other people sell this inverter with the internal bond present), then 120V potential is present on the case of the unit. Yikes!

I have seen people mention adding a second grounding rod, which could essentially create a ground loop. Depending on the environment for which the system is mounted, this could be problematic. Charge gradient across earth ground is always present, and lightning events in certain environments can cause high voltages to travel through the equipment. Again, there needs to be a standard for grounding these systems if it is being used with north american grid.

I use the LV6548 for my main system, and when connected to grid with ac input terminals, I need to use the grounding conductor. No exceptions. Sure, it might work. But I am not going to risk that. My system is designed for offgrid use with north america, so that is how it is setup.

 

[Will Prowse]

Exactly. I think most of this brouhaha is due to opinions and not fact based. I'm confident that Signature Solar are doing their due diligence as evidenced by the drawing they issued and the statement that their testing and analysis of the manufacturer ground screw removal solution. It may come to light that Growatt removed the ground-screw standoff, or have insulated this under the board. It may also be changed in future US versions of this inverter. Both good resolutions in my opinion. I would even consider using a syringe to pump some silicone into the ground screw hole and between it and the case if necessary. My plan is to first transfer all the parasitic and base load circuits of my house to the Growatt 5000ES (with AT) and then add circuits until I max out my self consumption. I have the inverter set to SBU so when I run out of daily solar it consumes the 14kWh battery and then switches to utility. My time of use rates are lowest overnight so I may even charge the battery to time shift some of my grid usage to the cheaper rate in winter. All of these things are available with the 5000ES and I can monitor everything with their app. In the past I have used Tristar TS60MPPT charge controllers for my solar but they require more complex wiring for short strings because they're only a 150 volt max.

Opinions? When did the differentiation between North American and European grid ground/neutral designation be considered "opinion"? These are clearly defined issues here, not personal opinions.

 

[Will Prowse]

I don't know of any European inverters that can run 60Hz and 240 volts. They run 220 volt @ 50Hz. It's an international inverter that has had the European use NG bond screw removed at the factory. It would not work in Europe. If you have some proof that there has been failures on this inverter in North America, please share it or if not please wait to see if there are changes required after Signature Solar completes their testing and analysis. Most of us that are following this discussion are doing so because we own and use these inverters or are considering buying them to suit our specific purpose. By your own videos you neither own nor have tested one and I don't recall you saying that you are an electrical engineer. There is a Canadian company who just recalled all these inverters because they hadn't done their due diligence and purchased the inverters unmodified with the bond screw in place. I'm in Canada but purchase them from Signature Solar because they have done their homework and had the manufacturer remove the ground bond to make them safe. If you are concerned about someone being dumb and switching off the AT breaker with the system in service, this can be easily resolved with a lock on that breaker.

Why did you not buy a North American specific inverter?

220/230/240AC is all the same.

This inverter has the option to do 50/60Hz, which is the same as north american inverters etc. It is not hard to add this into the software.

The manual states 230AC and 50/60Hz:


The "certificate of conformity" seems to match with EU standards. The North American Inverters do not have this certificate:

DIRECTIVE 2014/30/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL can be found here: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32014L0030

I would have to say that it is designed for Europe. Not North America. Can you show proof that this inverter is certified to be used in North America?

Signature solar "test and analysis" are a few guys just like us, trying to think of a way to write up a schematic that everyone can follow to figure out a safe way to use the product. A product which is not designed to be used in North America.

No, I do not own this inverter, because I live in North America. It would be quite silly for me to use one of these in my video. It is not worth the headache. But there are people who live in North America that are using this inverter, which can cause safety issues. I do not need to be an electrical engineer to figure this one out, it is pretty straightforward.

Signature Solar did not do their homework. You can tell by the schematic they showed. If they did their homework, they would have shipped out these European inverters with an accurate schematic, or had it certified for use in north america.

 

[Bud Martin]

I wonder if SS actually perform Hi-Pot test.

AC DC Hipot Test

Programmable Automated Test Equipment and Systems for Power Conversion, Electric Vehicle, Battery, Energy Storage, PV Inverter, and Mil/Aero.

www.chromausa.com

BTW, my MPP Solar US unit, PIP-1012LVS can be set to 50 Hz or 60 Hz using front panel parameter setting.

 

[hipringles]

It would be nice to be able to return my 5K ES's and autotrans so i can buy 2x LV6548 :/

Alteast mine are only used off grid, so only half the problems of this thread exist

 

[12VoltInstalls]

I don't recall you saying that you are an electrical engineer.

purchase them from Signature Solar because they have done their homework and had the manufacturer remove the ground bond to make them safe.

I am not an EE either - and certainly not as knowledgeable and experienced as WP.

However - there are designing EEs that have been posting here. They have pointed out flaws that at my level I never would even have thought of but that’s what they do/avoid every day in their careers.

As these experienced and knowledgeable members have explained: merely removing a screw has not made them safe although you erroneously stated that in the voice of fact.

Further, signature solar’s own posts here have affirmed their “aha!” - they didn’t think of these issues or how they might develop in field use. Their flurry to test the scenarios and matriculate to design and away from desire do not correlate with your claim for which there is no substance to defend based on the information posted here to the contrary.

Going into attack or defense mode on Will (or SigSol for that matter) is neither beneficial nor will it solve anything. Some concerns were aired, SigSol responded, and from all appearances it sounds like they are interested and intent on fixing the issues. Will didn’t attack, SigSolmdidnt attack; neither should you.

 

[Sky-HHI]

I would think that if Growatt did modify these units at the factory that they would identify or labeled the units as modified and include this information on the unit to make sure they are not used in an European system. SS were the only people who knew that these units are modified and only now have released this information. I wonder who really did do the modifications , Growatt or SS??

 

[Samsonite801]

Did anyone here buy a couple of these 5k ES Growatts with the transformer solution, and having serious buyers remorse now and want to sell it to me for super cheap (just so I can have a fun toy to play with)...

You probably don't want to run the risk of putting anything you own or other people into harm's by way now, so maybe you'd rather just sell the stuff (in the name of science / research / forensic study)...

I promise I won't kill anyone with it...

Besides, someone's got to check that ground standoff and measure the gap, and see if it was removed properly.

 

[robby]

I would bet that 3/4 of all off grid inverters sold and used in North America are not UL listed. The electrons don't care if they are in Europe or Murica. Most electrical equipment is built in China for international markets. with the exact same components and acceptable voltage and frequency range for all markets. If Signature Solar did not do their homework how come they are the only company I have found selling these who identified the ground bond as an issue and worked with the manufacturer to resolve it? You can't have it both ways. If you acknowledge that there is a problem with buying and using the "European" version direct from China with the required NG bond screw installed, then you also have to give credit to SS for identifying and working with the manufacturer on a solution. Signature Solar is not the manufacturer. If it turns out that the "arc gap" to the standoff continues to be a safety risk, it can also be resolved with some redesign by Growatt.

You could bet but you would be completely wrong. The DIY market for solar sales is a small section of the market.
Most people hire an installer and get their systems Grid tied and certified. They can then get any Tax rebates and sell back credit.
Most off grid systems are also installed by professionals. The fact is that most people do not like to mess around with high voltage electricity.

Companies like Enphase, Sol-Ark, SMA, Outback, Schnieder are some of the brands that are pushed by most Installers and in most cases they won’t install uncertified equipment.

 

[Quattrohead]

PeteB sounds like a shrill for someone.
Look, it's a great unit with many good features and when Growatt design and build a 120V version of it, they will knock it out of the park.
But for now, the 240v unit is not made for the USA electrical system and the bodge's to make it work here are unsafe.
Yes it could work for years with no problem, but safety is just like...well actually is insurance for when/if something goes wrong.

In fact, here is a perfectly safe use for it, powering a stand alone 240v HVAC system from panels and batteries with no connection the the home AC.

 

[Quattrohead]

Who is going to show us the bonding screw removed and the circitry around the area ?
I bet no one who sell's it LOL

 

[Hedges]

In fact, here is a perfectly safe use for it, powering a stand alone 240v HVAC system from panels and batteries with no connection the the home AC.

Could be, so long as you have a 240V only HVAC system.
A 240V window air conditioner (3 prong plug) could be it.
My HVAC system was installed as a 120V gas furnace plus 240V AC compressor. Blower motors and transformer are 120V.

You could still make this work but would still need a transformer. Autotransformer OK, but instead of 120/240V with centertap grounded, it would be fed with 240V having one side grounded. Be sure to wire 120V circuit to furnace with "Neutral" tied to that grounded wire (not to centertap), because only one leg is switched.
You would want transfer switch(s) so both furnace and A/C compressor can be fed from utility as well.