How to solve N/G bond problem with my cheap AIO ?

[EliteSolar]

Hi All!

There is a problem with the N/G bond and my setup .

I live in Europe, 230V and the N/G bond is made outside of my house.

So I have 3.1kw panels with a 3.6kw hybrid AIO ( EASUN SMG II ) that can run batteryless but also "blend/mix" power with the Grid.

I don't use batteries.

My model never bonds N/G and relies that the bond is made with my grid .

So when grid is off ( AC IN ) my inverter powers the loads just with solar panels directly, but then it goes into "battery mode" and loses the N/G bond. I tested the volt between neutral and ground and it was 160V and my ground tester says GROUND NOT OK. Of course everything works fine when there is AC IN because the AC IN is already N/G bonded and that carries through the inverter "Line Mode".

I understand the solution is to get the grounding box to connect to the dry connects and enable the option "When in battery mode , trigger the grounding box to make the N/G bond"

But I have some questions :

1) Since I will always have AC IN connected , I understand when the grid goes down , most of the time only L is cut and not N/G , does this mean the bond continues to work ? Or does the inverter senses no volt between L and N and cuts the connection and works in battery mode ? I guess the 2nd ?

2) Since there is hardly any grid disconnects and I plan to always use the AC IN , I understand the problem will be like 5 hours per year . If there is no grounding those hours , and it is daylight the solar panels will directly feed the inverter AC OUTPUT in "battery mode" ( without battery ). Does the RCD somehow protects me during those hours ? I've read various reports that the RCD would protect me and others that grounding is needed for RCD to work. Others say that for some functions the RCD protects you but for others it needs ground ? I still don't like the idea that the will be no ground for those 5 hours but if the RCD protects me, then I guess it's not that bad ?

3) People that have asked MPP and EASUN and I have read that twice in the forums , that they suggest you bind AC IN's Neutral and AC OUTPUT Neutral ? Is this correct ?! Is this really a solution for the N/G bond problem ? Doesn't sometimes the grid cut the N too ? Is this safe ? Or have I misunderstood something ?

4) Is there anyway I can just switch off the inverter when the grid is down ? I don't care if my system doesn't work when the grid is off because that hardly happens ( maybe 5 hours per year , some years ) . Is there any priority mode or any setting that would do that ? For me that would be my best solution because I don't have to worry about the N/G problem and if the grounding box is working correctly , plus I don't have to buy the grounding box. If there is not setting to do that , is there any DIN rail switch that will disable power if no grounding is detected maybe ?

5) If there is no workaround, I can always buy the grounding box , no problem, its like 50euro . I still think the inverter is good value since I only paid 430e , so still less than 500e for an AIO 3.6kw that works batteryless and can blend/mix power from grid.


I was just wondering how other people have tacked this problem in a similar scenario, it would be the same running it with batteries or batteryless , they would go into the same "battery mode" when there is no AC IN ( grid ) .

Thanks!

 

[Bud Martin]

Regarding to RCD (GFCI) and grounded/un-grounded, without Neutral- Ground bonded:
It will still offer protection, the GFCI will detect the un-balanced current between Line and Neutral that happens for any reason so it will trip and disconnect both Line and Neutral from outlet.

Earth grounding - Off grid - Bed rock

Do I need earth grounding in a full off grid system? Here on the Yucatan we have around 50cm (20 inch) of dry, sand like soil. Then comes bed rock. On top we have pretty strong storms with lightning and thunder.

diysolarforum.com

 

[EliteSolar]

So does this mean it would relatively safe to run ungrounded with RCD for those 5 hours per year when my grid is down ? Am I risking anything ?

 

[mrzed001]

EASun inverters do not have an internal PE-N relay
The best solution is to use an external PE-N relay.

The cheap solution is to connect N_in to N_out in your inverter

The red line in this picture:

 

[mikefitz]

The RCD will not protect unless there is a neutral to protective earth bond. Use a relay to make this bond, active only when there is no grid power.

 

[EliteSolar]

Binding grid's neutral and my inverter neutral is fine all the time ? What if N is also cut when the grid is down ? that is a possibility no ?

I guess I will buy the external grounding box ... but...

Why so many conflicting reports about RCD will protect/won't protect without neutral/ground bond ?

 

[EliteSolar]

It seems many people have recommended that , Ian from watts247 , EASUN support , MPP solar support , they all said you can connect grids ac in neutral with inverters ac output neutral. Is this safe ? Are there any complications doing that ? the only thing I can think is when the grid is down there is always the possibility N is cut too right ?

 

[mikefitz]

Why so many conflicting reports about RCD will protect/won't protect without neutral/ground bond ?

section 7.

https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

 

[meetyg]

Binding grid's neutral and my inverter neutral is fine all the time ? What if N is also cut when the grid is down ? that is a possibility no ?

I guess I will buy the external grounding box ... but...

Why so many conflicting reports about RCD will protect/won't protect without neutral/ground bond ?

I'm not sure how your main distribution box is wired, or how your country's electric system works, but in my case (220v single phase), I have a main AC breaker, and after that a main RCD. From my testing, if I shut down the main RCD, I loose the N-G bond that comes from the grid, because the Neutral is also switched.

As for when the grid is down, I guess it depends... I suppose the electricity company might also shut down the Neutral coming to your house, in case of a fault or maintenance.

So in short if you are connecting Neutrals, you might be fine (and will have N-G bond) ONLY if the grid goes down, but Neutral wasn't switched from the power company.
Also, if only the main RCD pops (because of an electrical fault/short), again you will not have the N-G bond.

It might be possible to get the main Neutral before the main RCD, but I am reluctant to go that way myself. Sounds too risky to me.

In summary, the Neutrals connection will only have you covered part of time.

Does your inverter have a dry-contact or relay that will close when it's in off-grid mode?
Seems that newer inverters removed that feature from their dry-contacts in favor of using it to signal a generator to start in case of low battery. Some inverters have the option to choose how the dry-contact works (for generator signal or for external bonding relay).

 

[CPet]

I guess the only proper solution is to setup a relay to connect PE and NEUTRAL out, triggered by loss of mains (L in and Neutral in). Ie. relay is OPEN when mains has power and closes when its not powered.
That should work well I think?

 

[meetyg]

I guess the only proper solution is to setup a relay to connect PE and NEUTRAL out, triggered by loss of mains (L in and Neutral in). Ie. relay is OPEN when mains has power and closes when its not powered.
That should work well I think?

That will work but only if AC IN Neutral is permanently connected to AC OUT Neutral.

Example scenario:
You have AC IN connected, grid is fine, but the inverter chooses to power the loads from solar and/or battery. This could happen depending on your settings on the inverter.

Some people want to maximize their solar power, so they choose settings that prioritize solar/battery usage over grid usage to power their loads.

In this case, the relay will open because grid exists, but actually AC OUT is not N-G bonded.

If you also connect both Neutrals, then when grid exists, you will benefit from the grid N-G bond, and the relay will only close when grid is down.

 

[EliteSolar]

That will work but only if AC IN Neutral is permanently connected to AC OUT Neutral.

Example scenario:
You have AC IN connected, grid is fine, but the inverter chooses to power the loads from solar and/or battery. This could happen depending on your settings on the inverter.

Some people want to maximize their solar power, so they choose settings that prioritize solar/battery usage over grid usage to power their loads.

In this case, the relay will open because grid exists, but actually AC OUT is not N-G bonded.

If you also connect both Neutrals, then when grid exists, you will benefit from the grid N-G bond, and the relay will only close when grid is down.

Thats not how it works with my inverter and Cpet is correct.

When you have AC IN the inverter will always use the NG bond from the grid , no matter the setting or program.

It will only lose the NG bond not when the grid is down , but when they CUT Neutral too ( they usually don't but they can ) .

 

[meetyg]

Thats not how it works with my inverter and Cpet is correct.

When you have AC IN the inverter will always use the NG bond from the grid , no matter the setting or program.

It will only lose the NG bond not when the grid is down , but when they CUT Neutral too ( they usually don't but they can ) .

Are you sure?
Usually the AIO inverters have a relay that either connects AC IN to AC OUT when in bypass/line mode, or disconnects them when working in battery/solar mode.

I would suggest you do a voltage check between output Neutral and Ground, when AC IN is connected, but inverter is supplying power from battery. If you get more than a few volts AC, there is no bond.

Some inverters have Neutral in and Neutral out already connected internally (common Neutral) but from what I know this exists in more high end inverters.

 

[EliteSolar]

Yes Im sure , there is internal bond. My model is 400euro 3.6kw SMG II . It will only lose the bond when the they cut grid's N. The problem is that there is no relay to switch when it looses grids N.

 

[alfonsis]

It seems many people have recommended that , Ian from watts247 , EASUN support , MPP solar support , they all said you can connect grids ac in neutral with inverters ac output neutral. Is this safe ? Are there any complications doing that ? the only thing I can think is when the grid is down there is always the possibility N is cut too right ?

I'm dealing with the same question because I want to integrate my EASUN REVO Series IGRID VE II Hybrid Inverter into the residual home power system.
Does anyone have authentic information from EASUN Support that it is possible to connect the AC IN N (Neutral) terminal to the AC OUT N (Neutral) terminal on the IGRID VE II Inverter without damaging the device, still using all the operation modes ( AC, AC+PC, Battery ) ?

As i checked with oscilloscope, in Battery Mode the voltage on the AC OUT N (Neutral) terminal is floating (compared to the voltage on AC IN Neutral).
If you connect the AC IN (N) terminal with AC OUT (N) terminal, (tested with Resistor 33kOhm), there will be a drain current to Earth Ground and a RCD will trip (if you would use an RCD on the primary side). So i will only use a overcurrent decvice on the IN side to avoid this problem. But i dont know if i will damage the inverter electronic components if i do so. This is the question.
Unfortunately until now i could not get a detailed answer from EASUN support.

 

[mrzed001]

I'm dealing with the same question because I want to integrate my EASUN REVO Series IGRID VE II Hybrid Inverter into the residual home power system.
Does anyone have authentic information from EASUN Support that it is possible to connect the AC IN N (Neutral) terminal to the AC OUT N (Neutral) terminal on the IGRID VE II Inverter without damaging the device, still using all the operation modes ( AC, AC+PC, Battery ) ?

Does EASun have a support ?
My only experience is that they want to get rid of you.
And even when you reach them ... non working Firmware upgrades, do not want to replace dead on arrival inverters ... etc

 

[EliteSolar]

There is no support, but noone will offer you a hybrid 3.6kw at that price point , so its like all those lifepo4 they buy here in the forums . No support and usually grade B swollen cells but still worth it and people buy it.

If you expect a 3.6kw hybrid that works (maybe) good for less than 430e shipped I think you are being unrealistic anyway.

You seem to suggest MPP or Voltronic but as far as I know MPP and Voltronic do not manufacture a very similar product at a similar pricepoint ( at least when I looked at it ) . If I'm wrong, please provide us a link and prove us wrong.

As long as you know what you are getting , that's fine . I would still choose the SMG II over MPP or Voltronic because noone will ship a functional unit at 430euros at my door ( even without support or PE-N relay ) ,at least when I checked.

If it arrives dead on arrival you have to deal with aliexpress and if not, then your credit card company. If it goes bad after a month, you played russian roulette and lost. If you dont want to play russian roulette buy a victron/sma whatever. But dont be fooled that you can get a 3.6kw hybrid inverter for 430e shipped at your door. You make it seem like Voltronic or MPP will instantly replace your model or ship you a new one, I highly doubt, that. Many people here have also support problems with MPP. Who will pay for you to ship this model back to China/Taiwan ? Is there are EU office that will accept the returns ? As far as I know , no .

I don't support EASUN , I just want to say that if you know what you are buying it might make sense to you to buy a unit from them.
Also, I highly doubt buying a unit from Voltronic or MPP will give you much better support.

 

[mrzed001]

There is no support, but noone will offer you a hybrid 3.6kw at that price point , so its like all those lifepo4 they buy here in the forums . No support and usually grade B swollen cells but still worth it and people buy it.

If you expect a 3.6kw hybrid that works (maybe) good for less than 430e shipped I think you are being unrealistic anyway.

You seem to suggest MPP or Voltronic but as far as I know MPP and Voltronic do not manufacture a very similar product at a similar pricepoint ( at least when I looked at it ) . If I'm wrong, please provide us a link and prove us wrong.

As long as you know what you are getting , that's fine . I would still choose the SMG II over MPP or Voltronic because noone will ship a functional unit at 430euros at my door ( even without support or PE-N relay ) ,at least when I checked.

If it arrives dead on arrival you have to deal with aliexpress and if not, then your credit card company. If it goes bad after a month, you played russian roulette and lost. If you dont want to play russian roulette buy a victron/sma whatever. But dont be fooled that you can get a 3.6kw hybrid inverter for 430e shipped at your door. You make it seem like Voltronic or MPP will instantly replace your model or ship you a new one, I highly doubt, that. Many people here have also support problems with MPP. Who will pay for you to ship this model back to China/Taiwan ? Is there are EU office that will accept the returns ? As far as I know , no .

I don't support EASUN , I just want to say that if you know what you are buying it might make sense to you to buy a unit from them.
Also, I highly doubt buying a unit from Voltronic or MPP will give you much better support.

First hybrid means grid-tie + off-grid. That can sell to grid. Please learn first the name of the system





EASun started this marketing BS that they sell Hybrids ... because it sounds "better"
Really they only misleading the customers. They sell Off-grid (with grid support) inverters.
Hybrids are the MPP Solar MPI alias Voltronic Infinisolar (and Deye/Sol-Ark). They can sell to grid.


You can read more about fake/clone MPP Solar inverters here:

MPP Solar Inc » Fake MPP Solar Inverters – how to avoid being fooled

www.mppsolar.com

It seems you never ever had to service an EASun inverter. Or an MPP Solar. You will see the difference :D

 

[alfonsis]

I'm dealing with the same question because I want to integrate my EASUN REVO Series IGRID VE II Hybrid Inverter into the residual home power system.
Does anyone have authentic information from EASUN Support that it is possible to connect the AC IN N (Neutral) terminal to the AC OUT N (Neutral) terminal on the IGRID VE II Inverter without damaging the device, still using all the operation modes ( AC, AC+PC, Battery ) ?

As i checked with oscilloscope, in Battery Mode the voltage on the AC OUT N (Neutral) terminal is floating (compared to the voltage on AC IN Neutral).
If you connect the AC IN (N) terminal with AC OUT (N) terminal, (tested with Resistor 33kOhm), there will be a drain current to Earth Ground and a RCD will trip (if you would use an RCD on the primary side). So i will only use a overcurrent decvice on the IN side to avoid this problem. But i dont know if i will damage the inverter electronic components if i do so. This is the question.
Unfortunately until now i could not get a detailed answer from EASUN support.

 

[alfonsis]

In the meantime I got this answer from avy@easunpower.com:

"The NEUTRAL terminals of AC IN and OUT are not allowed to be connected, and doing so means that the AC IN and OUT will be connected in series."

I am still confused, now on a higher level....
(see the schematic with my proposed wiring)
Is anybody out there with a schematic of a similar AIO Hybrid Inverter like this one ?