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dayandnight avatar image
dayandnight asked

ESS system doesn't react not balanced to high AC-load

Hello Specialists,

I run since several weeks a 3-phase ESS installation with Multiplus-II 3000, 48V, a grid based 3-phase PV and a 8 pieces Pylontech stack with US2000. It works quite okay and perfect. But based on certain circumstances it has behaviours I don't understand. I hope somebody can have a look and give my feedback.

On L3 is charging a Nissan env-200 with about 3,6 kW. Based on the remote console I see that the systems buys AC energy from the grid L3 with 1,2 kW and 3,2 kW is discharged in DC from the batteries. PV is very low, is equal to 0. The ESS system delivers/buys in total about 4,4 kW energy for a total AC load of 3,9 kW and with respect to yield of converting DC to AC I think this balance is correct.

I understand that a Multiplus-II 3000 is only able to deliver 2,4 kW AC which fits perfect with the grid buy of 1,2 kW to the total of 3,6 kW load on L3.

Question: Why is "no-traffic" on L1 and L2?

There was some time ago a similar discussion from @gnagflow but I couldn't find there a final solution. As I didn't wanted to hijack his thread I made my own question. But in this thread there was the hint:

... you have to turn phase compensation 'off' to get ...

I tried both settings the standard, "total of all phases" as recommended as standard

and "individual phase"

but it didn't change in behaviour of L1 and L2! It looks to me, that the Multiplus for L1 and L2 are in standby, isn't it?

I checked what could cause this "unbalanced" answer of the ESS-system. There was no battery discharge limit, it was set for 200A, the battery temperature was normal with 22°C - I have seen in the past discharge value of the batteries up to 180 A for high 3-phase AC loads, so each Multiplus is able to use individually 60 A to do it's job.

In Victrons ESS documentation there is mentioned:

"Phase compensation enabled (default & recommended)

ESS balances the total power (L1 + L2 + L3) to 0 W.

Intelligent optimization of the balance between the phases

ESS intelligently optimizes the balance between the phases -
as far as possible."


"as far as possible" - Where is my missunderstanding or my problem?

What can I do to puzzle it out?


DayAndNight


MultiPlus Quattro Inverter ChargerESS
multiphase-02.jpg (19.9 KiB)
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display-ev-charging-16.jpg (56.2 KiB)
display-ev-charging-17.jpg (42.0 KiB)
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·

Can you make some more screenshots of the ESS settings?

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dayandnight avatar image dayandnight Matthias Lange - DE ♦ commented ·

Hello @Matthias Lange - DE,

here are the screenshots of the ESS

If you want to see something else, don't hesitate to ask for.

DayAndNight



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3 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @DayAndNight

the phase optimization is mostly 'invented' to prevent feed-in from PV inverters, but what your seeing here is the limitation of the phase compensation: ESS does not know that the inverter doesn't have enough capacity to feed all the loads.

Most systems are sized so that 'normal loads' can be provided by the inverters, in this case it cant.

This might be improved in feature versions, but not sure if and when.

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dayandnight avatar image dayandnight commented ·

Hi Daniël!

Thank you for your answer! There are several reason why your answer is somehow confusing and astonishing for me.

First I am not sure if my English is good enough to understand

"ESS does not know that the inverter doesn't have enough capacity to feed all the loads"

therefore to point it out and to understand in detail my question A) and B)

A) Do I understand your answer correctly like this, that ESS controls for each phase individually and separately the flow of energy which can be handled individually by each of the specific inverters? Correct?

B) Today there is no calculation from the ESS system to balance all three phases common? Correct? But perhaps there might be a solution in future for this?

How do I have to change my setup to handle a load with 3600W ?- Here some more questions

C) For my example would it helpfully and work when I would have a Multiplus-II 5000 which is able to do 4000 W power? So the 5000 inverter could do the required 3600 W power in my example? (Of course it has to fit what the batteries are able to deliver, please assume the batteries can do any power which is being needed)

D) But when there would be a big load with 5500 W on single phase L3 it is again with the bigger Multiplus-II 5000 the same problem as in A) / B), that the ess system than buys from grid 1500W and the other two inverters will still stay in standby? Correct?

E) What happens when there are two Multiplus-II 3000 parallel for each phase? Would it be than possible to handle a AC-Load up to 4800W completely from the batteries?

Sorry for asking so much, but for me it is important to understand in detail. I am planing for several customers charging stations for EV cars. Energy should be collected during the day in batteries and at the evening when the car returns empty it should be loaded only from the batteries and not from the grid.

DayAndNight

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ dayandnight commented ·

Hi @DayAndNight

Most answers you already have from Ossi,

Yes the system tries to get total grid setpoint as requested, but if an inverter cannot supply the demand, grid will be used.

for EV charging: use a 3 phase supply to the car, more efficient and balanced.

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gnagflow avatar image gnagflow Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

It is very expensive to change the electric vehicle to get any that charges with 3 phases....

The only way I figured out is a very expensive transformer which again burns energy....

EV‘s are very frequent unsymmetrical, unfortunately.

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dayandnight avatar image dayandnight gnagflow commented ·

Hello @gnagflow,

perhabs you should think aboot changing / adaptation of your wallbox. I am working to adapt my wallbox to the actual limitation of the ESS. I use a Siemens LOGO! to control the wallbox controller. I am working in the moment to get thru network data directly from the GX device. Based on this data I will controll the EV charging current as low as I need to be lower than my Multiplus-II can do. Of course charging my Nissan takes with this strategy longer. But I don't care if charging the EV is finished at 10 pm, 1 am or 4 am

DayAndNight

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dayandnight avatar image dayandnight Daniël Boekel (Victron Energy Staff) ♦♦ commented · 
for EV charging: use a 3 phase supply to the car, more efficient and balanced

Hello Daniël,

thanks for your answer. You are right 3-phase chraging is any way more efficient and balanced. But unfortunately it isn't simply like this just to select 3-phase charging when charging an EV. Here a list of cars which are only able to load with one or two phase - and with this cars you don't have the choice to choose 3-phase charging. Sometimes it depends on the country where you buy the car. BMW delivered some time in the past to Switzerland BMW i3 94 Ah modell only with one phase charging. In Germany you had the choice for 94Ah modell to pay more and get 3-phase charging.


Man. Car
Phase Power
BMW i3 60Ah (optional) Typ2 1 7,4 kW (1 × 32 A)
BMW i3 60Ah (serienmäßig) Typ2 1 3,7 kW (1 × 16 A)
BMW i3 94Ah (optional) Typ2 1 11 kW (3 × 16 A) | einphasig 7,4 kW (1 × 32 A)
BMW i3 94Ah (serienmäßig) Typ2 1 3,7 kW (1 × 16 A)
Citroën Berlingo Electric Typ1 1 3,2 kW (1 × 14 A)
Citroën C-Zero Typ1 1 3,7 kW (1 × 16 A)
Citroën e-Méhari Typ2 1 3,7 kW (1 × 16 A)
Hyundai Ioniq Elektro Typ2 1 7,4 kW (1 × 32 A)
Hyundai Kona Elektro Typ2 1 7,4 kW (1 × 32 A)
Jaguar I-Pace Typ2 1 7 kW (1 × 30,5 A)
Kia e-Niro Typ2 1 7,4 kW (1 × 32 A)
Kia e-Soul Typ2 1 7,4 kW (1 × 32 A)
Kia Soul EV (bis Anfang 2019) Typ1 1 6,6 kW (1 × 28,5 A)
Mercedes Benz EQC Typ2 1 7,4 kW (1 × 32 A)
Mitsubishi Electric Vehicle / i-MiEV Typ1 1 3,7 kW (1 × 16 A)
Nissan e-NV200 (optional) Typ1 1 6,6 kW (1 × 28,5 A)
Nissan e-NV200 (serienmäßig) Typ1 1 3,7 kW (1 × 16 A)
Nissan Leaf (vor 2018, optional) Typ1 1 6,6 kW (1 × 28,5 A)
Nissan Leaf (vor 2018, serienmäßig) Typ1 1 3,7 kW (1 × 16 A)
Nissan Leaf (ZE1, optional) Typ2 1 6,6 kW (1 × 28,5 A)
Nissan Leaf (ZE1, serienmäßig) Typ2 1 3,7 kW (1 × 16 A)
Opel Ampera-e Typ2 1 7,4 kW (1 × 32 A)
Peugeot iOn Typ1 1 3,7 kW (1 × 16 A)
Peugeot Partner Electric Typ1 1 3,2 kW (1 × 14 A)
Renault Kangoo Z.E. (vor Mitte 2017) Typ2 1 3,7 kW (1 × 16 A)
Renault Kangoo Z.E. 33 Typ2 1 4,6 kW (1 × 20 A)
Smart EQ forfour / forfour electric drive Typ2 1 4,6 kW (1 × 20 A)
Smart EQ fortwo / fortwo electric drive Typ2 1 4,6 kW (1 × 20 A)
Streetscooter Work / Work L Typ2 1 3,7 kW (1 × 16 A)
VW e-Golf (bis 2017) Typ2 1 3,7 kW (1 × 16 A)
VW e-up! Typ2 1 3,7 kW (1 × 16 A)


I used the data above from going-electric. There you can have a look in detail. And if you have a look to the hybrid cars the 1-phase list is somehow bigger.

DayAndNight


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Meine_Energiewende avatar image Meine_Energiewende dayandnight commented ·

Same problem here with a Ford Explorer -> 1 phase 16 amps.

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gnagflow avatar image gnagflow dayandnight commented ·

Answer to E,

Tried to parallel two inverters and the third on another phase.... doesn’t help for our issue. The only solution could be to put all three inverters on one phase. Make an unsymmetrical system than victron software makes real phase compensation, but your grid supplier will not like you.
the only useful way would be an update from victron!

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gnagflow avatar image gnagflow commented ·

Hi Daniel,

people who make a big battery at home and have pv also like to buy an electric vehicle. Your system comes from boats but the future is a pv a battery an an ev. Unfortunately the ev‘s mainly have one phase chargers. So, it would be recommended that you put this simple advancement to you update list for ess, if Victron wants to satisfy the customer demands.

There are no symmetrical loads in real life, even when I cook. Another problem of your used algorithm is that the inverters are very inefficient at 100% of load (88%). So if all inverters work at 33% it is more efficient than one inverter works at 100%. Your algorithm has no single advantage in ESS systems. It is good for boats or camping issues or island mode.

for my issue, I buyed an expensive transformer (hinausgeschmissenes Geld) to make out of 400V (2 phases) —> 230v only to drive my car with the sun, when I come home late from work using recycled lion cells.

But now I can only use two of three inverters ...



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dayandnight avatar image dayandnight gnagflow commented ·

Hi @gnagflow,

I am interested how you did this? Is it correct you use an transformer 400 V / 230 V one phase and you connected it as example between L1 and L2? That's it? The 230V output is then used to serve the wallbox? Correct?

DayAndNight



(2)

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gnagflow avatar image gnagflow dayandnight commented ·

Yes, in general that’s it. A simple transformer that makes out of 400v —> 230v like this:

https://www.ebay-kleinanzeigen.de/s-anzeige/trafo-transformator-einphasig-400-230v-6-3kva/1407750579-168-3814?utm_source=copyToPasteboard&utm_campaign=socialbuttons&utm_medium=social&utm_content=app_ios


but this is not a perfect solution because of a efficiency between 90 to about 96% of it. Depending on the P/Pmax. Furthermore it has a standby power, you have to switch it... all not perfect. Futhermore, if you use a not galvanic disconnecting transformer like a „Spartrafo“ you need a suitable FI in the wallbox. Furthermore you need to earth on side of the output to have a „null“ and a phase

I got now a „juice phaser“ which costs about 900 Euro new for 320eur. It’s a spartrafo with switch in a switchcase, it switches of the Trafo by the use of the cp signal of my open wallbox. I only need some small modifications, cut off the juice connector and connecting the cp signal of the wallbox.

But all that isn’t nice compared to 5 new lines code that is needed done by victron to satisfy future customers. Mainly also because people who make high investments in three phase systems must be disappointed, to get something weaker than a single inverter for middle European standard of allowing compensating grid meters.

There are also some Trafos that make out of 3*400 the 230v. Something like this:

https://www.ebay-kleinanzeigen.de/s-anzeige/drehstrom-transformator/1080161587-168-6977?utm_source=copyToPasteboard&utm_campaign=socialbuttons&utm_medium=social&utm_content=app_ios

Which seems perfect, but this has very high lost, because it is made for 60Hz according to the information of the manufacturer.

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Christian Dorst avatar image Christian Dorst commented ·

Hello Daniël,

I can only confirm the experience of my previous speakers. I sold a three-phase MP-II 5000 system to a costumer of mine, with the intention to have enough power to load his car and keep his household on green energy. Unfortunately he drives a Hyundai with 1-phase 7.4 kW loader, and in the moment he is taking nearly half of the energy from grid when he needs to load his car fast. I agree with you, that 3-phase supply would be a solution and a better way of charging, but as mentioned by DayAndNight, a lot of EVs are connected by 1-phase with up to 7.4 kW.

As mentioned from others, this behavior is not what I suspected the phase compensation to be. So please consider a "Symmetrical ESS" as a practical solution for installation, your competitors on the on-grid market in D-A-CH do so too (all one-device 3-phase systems: Fronius Symo Gen24, Kostal Plenticore, ... but the SMA Sunny Island System in 3-phase setup too). I know your system is designed for off-grid solutions, but I think the on-grid market is a big fish too. And I would like to sell more Victron Multiplus solutions..

Best regards

Christian Dorst

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gnagflow avatar image gnagflow commented ·

Dear Daniel,

as you can see, within a short period of time already 5 very disappointed customers claiming the same problem with phase compensation in three phase systems. You can be sure, that the biggest market for your future is on-grid in combination with EV charging. So, my question, could you look at this thread again and discuss this with your team members? I am sure that people who get aware of this problem, will not decide any more for Victron. Your future customers will not make big investments in three phase systems that are not usable for the target group.

Can you provide a solution within a short period of time? Can you tell me the name of the file, where i can find the code, for updating it just for the community members? As described already by "Ossi" the new algorithm for on-grid three phase systems in ESS is much simpler than your old approach like:

What we expect for phase compensation is a symmetrical ESS feed:

Grid counter L1+L2+L3 = Pgrid

VEBusPower DeviceL1 Power= -0,333*Pgrid

VEBusPower DeviceL2 Power= -0,333*Pgrid

VEBusPower DeviceL3 Power= -0,333*Pgrid

----------------------------------------------

Here is the last community member who claims the problem:

Hello Daniël,

I can only confirm the experience of my previous speakers. I sold a three-phase MP-II 5000 system to a costumer of mine, with the intention to have enough power to load his car and keep his household on green energy. Unfortunately he drives a Hyundai with 1-phase 7.4 kW loader, and in the moment he is taking nearly half of the energy from grid when he needs to load his car fast. I agree with you, that 3-phase supply would be a solution and a better way of charging, but as mentioned by DayAndNight, a lot of EVs are connected by 1-phase with up to 7.4 kW.

As mentioned from others, this behavior is not what I suspected the phase compensation to be. So please consider a "Symmetrical ESS" as a practical solution for installation, your competitors on the on-grid market in D-A-CH do so too (all one-device 3-phase systems: Fronius Symo Gen24, Kostal Plenticore, ... but the SMA Sunny Island System in 3-phase setup too). I know your system is designed for off-grid solutions, but I think the on-grid market is a big fish too. And I would like to sell more Victron Multiplus solutions..

Best regards

Christian Dorst

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n-dee avatar image n-dee gnagflow commented ·

+1

Same situation here! 7,4kw e-car-charging on one phase.

I'm buying three more multiplus to solve that.

-> well I know: thats a total economic loss :-(

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gnagflow avatar image gnagflow commented ·

Hi Daniel,

there you see: every day the next econmic loss and unsatisfied customers:

N-DEE gnagflow · vor 6 Stunden

+1

Same situation here! 7,4kw e-car-charging on one phase.

I'm buying three more multiplus to solve that.

-> well I know: thats a total economic loss :-(

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derbernd avatar image derbernd commented ·

I have the same problem, with a 3 phase system, But a different view on the Problem. Load on L1 2,4kw L2,L3 nearly 0 (Grid 0W). So one Multiplus II runs at 2,4kw what is not very efficiency only 88,5%. If every Multiplus is Running on 800W (Grid 0W ) the efficiency is 95% based on Victrons efficiency curve. And that is saving a lot of Energy for me. Have a sunny summer.

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raphael avatar image raphael derbernd commented ·

I created a new question on the efficiency and longevity topic:

https://community.victronenergy.com/questions/92660/3-phase-unbalanced-ess-grid-feed-in-multiplus-ii-4.html


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ossi avatar image
ossi answered ·

Hi @DayAndNight,


i ve been following your explanation and issue. i've even commented on the issue your are referring to @gnagflow , how to look inside VenusOs, which i presume you will like:

https://community.victronenergy.com/answers/55524/view.html


---------------

As i understand the calculation of VenusOs for a 3 phase ESS system is not like anticipated when turning on the phase compensation:


What we expect for phase compensation is a symmetrical ESS feed:

Grid counter L1+L2+L3 = Pgrid

VEBusPower DeviceL1 Power= -0,333*Pgrid

VEBusPower DeviceL2 Power= -0,333*Pgrid

VEBusPower DeviceL3 Power= -0,333*Pgrid

So the Grid values over all phases are added to a total which is evenly distributed to all of the Phases of the ESS System. This means that the ESS System would only operate symmetrically, each inverter performing exactly the same value.

This is also common practice just to make sure not to add to any asymmetrical issues.

--------------------------------------

What Victron does when Phase compensation is On is, sending each individual inverter each value for the Phase for Pgrid for L1/L2/L3 and than deciding to charge or discharge only on the one phase that is the highest/lowest to make sure:

Phase Compensation enabled: ESS prevents circumstances where the battery might be charging on one phase whilst discharging on another.


---------------------------------

I personally think this issue is solved by either using a external EMS which will only send symmetrical requestes to ESS Setpoint L1/L2/L3 (Ess optimization must be external control) via modbus TCP server.

Or Victron will adapt the internal calculation for the ESS Setpoint and add a feature to the phase compensation, which could be called only Symmetrical ESS



VG

Ossi


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dayandnight avatar image dayandnight commented ·

Hello @Ossi,

thank you for your detailed explanation, which looks for me of a profound and deeply understanding of the situation. Great! Thanks!

I agree to your description and your implication.

I am somehow disappointed, because when started with Victron I read a lot of Victrons documentation as ESS Design & installation manual and there can be still read at 7.2 Three phase ESS: "ESS balances the total power (L1 + L2 + L3) to 0 W." and there is for my understanding no information that is might be ... or it can happen that ..... or be aware that ... and in my above example L1 (1 W) + 5 W (L2) + 1241 W (L3) with a total of 1200 W is far away from 0 W

I understand now, based on my real experience and discussions here the technical background but I had different expectations when I read "ESS balances the total power (L1 + L2 + L3) to 0 W." and I cross checked again the documentation, I could only find a note for maximum charge current not any other written restriction, I had now to discover.

I don't want to complain here. I have a work around for my 3,5 kW EV charging problem. I simply reduce and control the power for charging the EV car when no PV support is available to the load the single inverter is able to drive. So it takes longer to charge the car which is no problem for me if the car is fully charged at 10 PM or 1 AM in the night. The work arround is only simply to realize based on the wide possibilities and functionalities Victrons system is offering so it is still great for me!

You created already the name what I need and I think Victrons world is waiting for:

"Symmetrical ESS"

I am sure Victron has the potential to offer a solution for Symmetrical ESS, hopefully threads and disscussion like this one creates the priority at Victrons headquarter that we will have it very soon available.

DayAndNight

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gnagflow avatar image gnagflow dayandnight commented ·

I had the same disappointing experience, I read in several victron documentations that phase compensation works and there was no hint that it does not work in three phase systems, there is only one part in the documentation that really shows that it is not working for unbalanced loads when a load is greater than the max. Power of one inverter.

Everyone will make a disappointing experience who thinks to get e.g. 3*2.5kW but only received 2.5kW on a phase, all big loads can’t be served from battery, only during the day when pv produces a lot of power you can mostly serve the needs.

I changed from 1*5000VA to 3*3000VA to satisfy the grid provider but the system has much lower performance.

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gnagflow avatar image gnagflow dayandnight commented ·

This would be nice ...


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gnagflow avatar image gnagflow commented ·

Exactly what you say is what we expect as phase compensation, an external control does somehow adds an additional system that can fail which would be nice to avoid, but also requires a Development.

The more people raise the issue the bigger the chance that Victron adds the feature of real phase compensation to supply high unsymmetrical loads of electric vehicles.

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ossi avatar image ossi gnagflow commented ·

https://www.victronenergy.com/blog/2020/02/25/silent-3-phase-grid-parallel-ess/


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gnagflow avatar image gnagflow ossi commented ·

I read this before, nice marketing and when you loose grid the victron algorithm is great, but who looses grid. In my life I have seen a blackout for maybe 5 times for 5 minutes. I guess even this hotel hasn’t more blackouts seen in its life. Nice feature that is necessary on a boat but not at an ess system. Even the big hotel has probably unsymmetrical big loads from kitchen and heating. Symmetrical loads are the dream of the grid provider and only real in the big view, having 100 unsymmetrical houses makes together by chance a symmetrical load for the grid.

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ossi avatar image ossi gnagflow commented ·

@gnagflow right, i posted this due to the refernce of the external EMS used in the project with a Victron ESS and EV Charger ;)


BR


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woliver avatar image
woliver answered ·

Hi Everybody! I have the same problem. So it is very frustrating that victron offers no solution for this problem.

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