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radon238 asked

Multiplus Dual Phase with ESS, Is this Possible?

Victron Guides explain ESS in the Following Configurations:

  • ESS Single Phase
  • ESS Single Phase In a 3 phase system, (ESS only installed on Phase 1, and PV power then only supplemented to L1)
  • ESS 3 Phase in a 3 Phase System

Is there a Dual phase ESS?
On a Dual Phase Multiplus installation with ESS installed on L1 and L2, ESS does not seem to function correctly. It seems to work well for L1 phase, but on the L2 phase I get huge feed from the L2 inverter to grid (Even with Feed-in Disabled).

If the answer is NO, then don't bother reading further. If Yes, then please give me some advice on what I may be doing wrong.

The Physical Setup:
The Grid Supply is 2 Phases (The way the utility provider increased the current supply to the property is by supplying an additional 230V phase (The One phase is 0 and the other 240 degrees offset. i.e. 2 phases from a 3 phase utility transformer), This gives the property 2 x 80 amp Current.

2 X Multiplus II configured as Phase 1
2 x Multiplus II configured as Phase 2 (240 degrees)
Cerbo GX, BMS.Can Battery, SmartSolar MPPT's 30kw PV.
AC1 Current output was measured as balanced to under 10% variance between L1 inverters, and the same for the L2 Inverters)

Client Requirement:

Keep battery 100% charged. Use excess PV power, to decrease the grid consumption on L1 and L2.

Configuration:

Switch as a group Ticked (Required in order to select a Grid Code)
Grid Code selected (Required by ESS)
ESS Installed on all 4 Multi's
ESS Set to "Keep batteries charged"
Grid Feed-In Disabled (Feed in not allowed by the Utility Provider)


Fault Finding:
1) With ESS installed on only the L1 Inverters, the system functions as expected.
PV Power is only supplemented to the loads on L1 Inverters, L2 Loads are only powered from the Grid)

2) With ESS additionally installed on the L2 Inverters the L1 Loads continue to be powered by the PV power, But now the Total PV Power draw is increased dramatically, and the L2 Inverters Incorrectly Feed-In to the Grid.

2b) If the battery has been discharged, then This Feed-In does not happen, and the PV supplies some charging current + Load , and the Grid the rest. (No Feed-In happens until the batteries are fully charged).
I also get regular L2 overload warnings and overload shutdown even though the Load is only 4kw (well under the 8kw combined L2 inverter capability)

Your assistance will be appreciated - With the ESS Assistants ;)

ESS
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2 Answers
Warwick Bruce Chapman avatar image
Warwick Bruce Chapman answered ·

We use this configuration fairly often without issue. It is definitely supported - and you can choose the phase angle for the split phase system during setup in either VictronConnect or VE.Bus System Configurator:

1674043121096.png

Source: https://www.victronenergy.com/blog/2021/02/02/victronconnect-parallel-three-split-phase-setup-and-more/


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radon238 avatar image radon238 commented ·

@Warwick Bruce Chapman Thanks for the Answer.

More specifically my Question was more an issue with ESS. I cannot seem to get ESS working in a Dual phase Setup.
Single Phase ESS works.
Three phase ESS works
Dual phase ESS seems to give me Issues.

Are you installing ESS, with SmartSolar DC MPPT's on your Dual phase systems?

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radon238 avatar image
radon238 answered ·

I managed to resolve the Issue:

The Answer seems to be YES - Dual Phase ESS does work.

How did I solve the problem?

I complete removed the ESS Assistant from all 4 the inverters, Wrote the Config to the Inverters.
Then Re-Installed the ESS Assistant on all the Inverters, and Wrote the config again.


What was the problem?
I suspect that the First time I installed ESS on the L2 phase, It did not install correctly. It installed as a Single phase master. (Not sure how I managed to do it wrong)

During the First Time install the L2 Master Assistant prompted me to Configure the "Dynamic cut-off" Voltage Values. The assistant does not give this prompt on a Slave config.

The second time I installed ESS on the L2 Master - The ESS Assistant did NOT ask me for the "Dynamic Cut-Off" Values. I suspect that it now knew that it was not the master anymore, and that the ESS master is on the L1 Master Inverter.

ess-dynamic-cut-off.jpg** The ESS Assistant "Dynamic cut-off" Configuration Screen is only Displayed for the ESS Setup on the L1 Master Inverter

I also configured Multiphase Regulation to "Individual phase" as the utility provider does not allow feed-in on any phase, and my phase loads are not balanced. (I realize there are some efficiency losses with this setting, but what else is there to do if you are not allowed feed-in ): )

After doing this I still had some small Grid-In values. "-100W" going into the grid sometimes. (Before the Ess re-install I was getting up to 1500w grid Feed-In)

This I resolved by setting the "Grid setpoint" Higher. This value needed to compensate for all 4 inverters.

ess-grid-set-point.jpgNow when PV is supplying the full load, I see the Grid value Fluctuate between 0W and 500W drawn from the grid, but never feed-In.


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