Deye Parallel 8kW not working the same

[mrzed001]

I think that the attached are the EU types of earth system.

Not only in TT but in all the other cases there is local ground too.
Really what you need I think is TN-C-S.
You get 2 wire: Line + PEN (N + PE because it is grounded on the transformer side too)
In the pic where PEN is separated to PE + N, there is the place for the local ground to connect.

I checked what would happen if I connected the local E to the incoming N and there would be a 4 A circulating current. Obviously one or both of the E connections are not that good most likely the one at the transformer since it is connected to the earth wire of the HT system. It needs this for the fuse protection on the HV line to the transformer to operate.

There is no problem with that. Leave it so.
And now make the Volt measurements again ... and they should be OK.
I think the inverter uses the ground for reference.

Any answer from Deye ?

 

[RWI]

Yes I agree a TN-C-S system with MEN links. I had already connected the Grid N to the local E and of course the N to E (local earth stakes) values all went down to Zero and the inverters are now probably better protected. We do however have a significant circulating current which is not envisaged in this configuration and not good practice. The problem comes from the connecting of the HV and LV earths at the transformer. Although we paid for the HV supply system it belongs to the power authority and we should not touch it and any attempt to ask for changes would be a waste of time. A combined HV and LV earthing system is ok and we use it for power generation systems but the earth impedance has to be no more than 1.0 Ohm.

Nothing from Deye. I guess that I am not surprised.

 

[RWI]

I just realised that the metering is within the circulating current that I have generated so I am going to have to remove the link again. I am not exactly sure how the meter works but my guess is that an increase in N current with no change to L will make the meter record more kWh.

 

[RWI]

Actually assuming that the transformer earth is at a higher potential the the building earth the N circulating current is in the reverse direction so maybe will not effect the meter.

 

[mrzed001]

Yes I agree a TN-C-S system with MEN links. I had already connected the Grid N to the local E and of course the N to E (local earth stakes) values all went down to Zero and the inverters are now probably better protected. We do however have a significant circulating current which is not envisaged in this configuration and not good practice. The problem comes from the connecting of the HV and LV earths at the transformer. Although we paid for the HV supply system it belongs to the power authority and we should not touch it and any attempt to ask for changes would be a waste of time. A combined HV and LV earthing system is ok and we use it for power generation systems but the earth impedance has to be no more than 1.0 Ohm.

Nothing from Deye. I guess that I am not surprised.

Usually local ground is connected to separated PE (but not a big difference)
You do not have anything to do with the HV transformer.
Just ground your local PE. And the MAN connection.

Here your local ground must be better than 10 Ohm. I have 2 pcs 4m ground rod (connected together)

And now do the test. How are the inverters working now? Error still exists?

 

[RWI]

Whatever I do with the grounding arrangement makes no difference to the problems with the inverters.

 

[mrzed001]

Whatever I do with the grounding arrangement makes no difference to the problems with the inverters.

OK. I was hoping it solves the AC overload problem.
Still no response from Deye?
Where did you buy the inverters? Alibaba? There you can complain too.

 

[RWI]

Deye need the wifi connection to check the inverters. I did not connect this because I don't like the idea of some Chinese server having control of my electrical system. I will have to try and connect it and then disconnect once they have their information but the connection process is not easy.

 

[mrzed001]

Deye need the wifi connection to check the inverters. I did not connect this because I don't like the idea of some Chinese server having control of my electrical system. I will have to try and connect it and then disconnect once they have their information but the connection process is not easy.

At least it does not have a camera or microphone ?
If they know how much power I use ... who cares
But you give me an idea. For the MPP Solar we have the RS485 protocol, so with a RasPi we can remote control it.
I have to check the Deye protocols ...

 

[RWI]

Camera and microphone don't worry me. Cyber attach on the network does. I have first hand experience of this on a system with a very secure gateway. There is no security on the Deye netwrok

 

[mrzed001]

Camera and microphone don't worry me. Cyber attach on the network does. I have first hand experience of this on a system with a very secure gateway. There is no security on the Deye netwrok

I like the local server solutions. Where I am the server, all the data is in my machine.

 

[RWI]

Yes I agree. The internet is a battle ground for the major powers and everyone else is a pawn. After many tries I finally connected the two inverters to the Deye server but through a dedicated router so all i have to do is turn it off..

 

[mrzed001]

Yes I agree. The internet is a battle ground for the major powers and everyone else is a pawn. After many tries I finally connected the two inverters to the Deye server but through a dedicated router so all i have to do is turn it off..

OK. I am interested what Deye will see and test with your inverters.

 

[RWI]

Hopefully they do not change anything without telling me. By the way I now have access to the logging server for these inverters and a lot more information than you can get from the screen. This is good but the security is my main issue.

 

[mrzed001]

Hopefully they do not change anything without telling me. By the way I now have access to the logging server for these inverters and a lot more information than you can get from the screen. This is good but the security is my main issue.

Never checked that. What extra info is there ?

 

[RWI]

There is more battery information and selectable trending including MPPT voltages which is good information for me. Unfortunately I could not find a trend of the battery SOC which I needed because it went from 50% (the limit set on the time of use) to 3% some time overnight. The battery has been charging from grid and then solar during the day and at the moment is 48% after adding 49 kWh. The battery is nominally 96 kWh (2,000 Ah) so it added 51% and went from 3 to 48% which is 45% so I guess that it is reasonably accurate now. I know that the inverter takes some time to set the battery SOC after starting but that was a huge change. I am going to check all the voltages to try and find the true state but have not started yet.

The good news is that Deye today updated the firmware/software through remote access (i do not know what they changed) and have fixed the MPPT problem and the slave is now working correctly and basically the same as the master. Obviously this did not fix the islanding issue and I have not yet informed Deye of this problem because I wanted to take them one at a time. I will be asking Deye about this issue in the near future.

 

[mrzed001]

There is more battery information and selectable trending including MPPT voltages which is good information for me. Unfortunately I could not find a trend of the battery SOC which I needed because it went from 50% (the limit set on the time of use) to 3% some time overnight. The battery has been charging from grid and then solar during the day and at the moment is 48% after adding 49 kWh. The battery is nominally 96 kWh (2,000 Ah) so it added 51% and went from 3 to 48% which is 45% so I guess that it is reasonably accurate now. I know that the inverter takes some time to set the battery SOC after starting but that was a huge change. I am going to check all the voltages to try and find the true state but have not started yet.

The good news is that Deye today updated the firmware/software through remote access (i do not know what they changed) and have fixed the MPPT problem and the slave is now working correctly and basically the same as the master. Obviously this did not fix the islanding issue and I have not yet informed Deye of this problem because I wanted to take them one at a time. I will be asking Deye about this issue in the near future.

Do you use lead-acid or lithium (LFP) battery with BMS ?
So the inverter calculates the SoC based on the current V or a BMS gives it to them ?

Relief that with a simple Firmware upgrade it is fixed It seems to be such a good inverter.

For the islanding to work correctly you need a relay (without it: Floating Ground). Or two? One for every inverter?

The other question I would pop to Deye is : Redundancy ? What happens when one of the inverters fails ? The other still works and gives power ? It is any difference if the master or the slave dies ? (because sometime sh-t happens ... like when you are 1000km away from home )

Also the first thing I would ask is the RS485 protocol for the inverter.
For the MPP Solar/Voltronic Axpert inverters we have it (there is already many RasPi solution).
And we can monitor, control, and log the inverter (local server).

 

[RWI]

Dumb lead acid batteries.

Yes it fixed that issue but I have others.

No Problem with UPS load its N is strapped to the Grid N which is MEN connected to earth at the incoming board basically following Deye diagram. My problem is the master inverter not disconnecting from the grid when the grid fails (110 V AC back feed). I have installed a separate islanding system that independently disconnects the inverters from the grid.

The master and slave work like a Union, One out All out !!! Even if you turn one off they both stop. Everything is still fed from the grid though so not such a big disaster. If you have a big problem with one you would have to turn off the parallel option.

I have looked at local monitoring and Solar Assistant (running on a raspberry) will connect to the BMS RS485 port for data collection and the Wifi remains connected.

 

[mrzed001]

Dumb lead acid batteries.

That can do dumb and unexpected things ?

Yes it fixed that issue but I have others.

No Problem with UPS load its N is strapped to the Grid N which is MEN connected to earth at the incoming board basically following Deye diagram. My problem is the master inverter not disconnecting from the grid when the grid fails (110 V AC back feed). I have installed a separate islanding system that independently disconnects the inverters from the grid.

Did you ground the PEN before inverter, separate to N+PE, and put a relay to the inverter inner N-PE bond ?

The master and slave work like a Union, One out All out !!! Even if you turn one off they both stop. Everything is still fed from the grid though so not such a big disaster. If you have a big problem with one you would have to turn off the parallel option.

I think MPP Solar works like one out other function perfectly. Or the slaves can die and the master have to work ...
At least for 1 phase I saw a test for that.

I have looked at local monitoring and Solar Assistant (running on a raspberry) will connect to the BMS RS485 port for data collection and the Wifi remains connected.

Solar Assistant is used for MPP Solar inverters. So it can be used for Deye too? Interesting.

 

[RWI]

Did you ground the PEN before inverter, separate to N+PE, and put a relay to the inverter inner N-PE bond ?

System is now exactly like a TN-C-S MEN system.

I think MPP Solar works like one out other function perfectly. Or the slaves can die and the master have to work ...
At least for 1 phase I saw a test for that.

The Deye are definitely both or none. I can sort of understand because everything is divide by two in the master and sent to the slave. The grid CT is only connected to the master so the slave would not work if not communicating with the master. Might have been possible for the master to keep going if the slave was lost but more complex logic. If you change certain settings in one they are automatically changed in the other.

Solar Assistant is used for MPP Solar inverters. So it can be used for Deye too? Interesting.

Yes they say SunSynk, Deye, Sol-Ark will work and seems like they have the same interaface