question

PeterM avatar image
PeterM asked

Meaning of Switch - "Inverter Only" Multiplus

What does new feature Switch "Inverter Only" actually mean on Multiplus/ Quattro? Does it mean ignor Grid or Generator? It is just opposite to Charger off ?

MultiPlus Quattro Inverter Charger
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4 Answers
Mark avatar image
Mark answered ·

Yes it means Inverter ON (only)- powered by the battery.

Charger OFF

AC Passthru OFF

Effectively AC In (if present) is totally ignored.

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adelante avatar image adelante commented ·
Is there a way that the Inverter only could be powered from the grid ?

Charger OFF

AC Passthru ON

DC Powered from battery

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sharpener avatar image sharpener adelante commented ·
Inverter Only disconnects the Anti-islanding relays on AC-In so there is no physical connection with the grid, see this thread.
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PeterM avatar image
PeterM answered ·

Will frequency still shift if connected to a Grid Tie inverter ?

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Mark avatar image Mark ♦♦ commented ·

Yes I expect so.

Do you have an off-grid system with grid-tie PV inverter connected to the AC out + 'PV inverter support assistant' loaded in the Multiplus?

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schollex avatar image
schollex answered ·

Hi,

I have an ESS-system with Multis+MPPT+batteries as well as AC-in-coupled microinverters.

During winter with low PV-yield, it's just perfect that the Multis also use the microinverter-power to charge the batteries.
But during summer with a lot of PV-surplus, it would be fine if (in the morning) the batteries would only be recharged by MPPTs instead of transfering the ACIN-surplus to DC.

This would save the Multis from the unnecessary tranfer-load.

I tried "Invert only", but as described in this threat, this mode seems only to supply ACOUTs, because the DC-surplus immediatly stops being transfered to ACin.

I assume my intention cannot be realized.

Bye

Alex

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jetlag avatar image jetlag commented ·

I have the same situation as you @schollex

I also want to load the battery only with the MPPT as there is more then enough solarpower during the day and instead I would like to see the AC-coupled Inverters to either directly supply the loads or to export the excess energy to the grid.

I did not find a solution for that yet, running a ESS System...

Maybe someone has an idea in the meanwhile...


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schollex avatar image schollex jetlag commented ·

Hi @Jetlag,

I found a solution. Just reduce Settings > DVCC > Maximum Charge Current to 0.

This parameter is a bit confusing:

  • the MPPTs charge the battery according to limitations which may be set within the MPPT-setup. The DVCC-limitation does not affect the behaviour of the MPPTs
  • if the current provided by MPPTs does not exceed the DVCC-current-parameter and if the gridmeter is below the ESS-setpoint, additional AC-power will be transfered to DC thorugh MP2
  • thus, with DVCC Maximum Charge Current = 0, you make the system to load the battery only with MPPT-power.

In my specific situation, I wrote a NodeRed-flow which dynamically adjusts the maximum charge current in dependance on battery-SoC and weather-forecast (remaining solar-power for the day) to gain 100% SoC short before sunset.

Bye, Alex

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nickdb avatar image nickdb ♦♦ schollex commented ·

Do not do this. It will affect how ESS works and put it into a #6 state. Victron do not want charging controlled by setting a CCL to 0.

MPPT's will be throttled as it clamps the entire DC bus.

It is also ignored by exporting.

Terrible advice to give someone who does not understand how the system works.


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schollex avatar image schollex nickdb ♦♦ commented ·
Hi @nickdb ,

would you please explain your concerns in details.

My system works perfect with CCL = 0.

In the morning, the battery is only charged with MPPTs.
My MPPTs are never throttling. As soon as the battery is full, the exceeding power is transformed through MP2 to AC.

In case of a low SoC, my NodeRed-flow raises CCL, so the SoC can be raised via MP2's AC2DC-transformation.

What problems do you see that I don't see or experience?

Regards,
Alex



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jetlag avatar image
jetlag answered ·

Thanks @schollex , but this solution does not work for me. I tried this before, and tried it again just right now, but then the whole system just stops charging. MP2 as well as the MPPT. I tried some number inbetween, like 1A...5A... then the energy is (more or less) split bei 50/50 from both sources... Maybe I have some other settings or different firmware versions... Well it's not that cruial for me. ;-)

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nickdb avatar image nickdb ♦♦ commented ·
Yes, because that is a terrible way to try restrict charging and how it is designed to behave.


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alexv avatar image alexv nickdb ♦♦ commented ·

Just a suggestion. I use the Multiplus on a boat and also just want to have the Pass-through mode enabled, while the MPPT charges the battery. To do so I have added the "Two Signal BMS" assistant. like so:

1712316008269.png


I connected the Aux input of the MPII to a relay output on the Cerbo. Now I can control the charger from the Cerbo / Node red.

Not sure if this would also work for you ESS setup.



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1712316008269.png (12.9 KiB)
jetlag avatar image jetlag nickdb ♦♦ commented ·

After some more thoughts to that, - I'm wondering why this should work at all?

DVCC is specially made to control the Battery current and voltage. So why it should not affect the MPPTs?

E.g. if you have multiple MPPTs, and they are able to deliver way more power then the battery can take, this is the mechanism to control the current. So why this should have no influene on the MPPTs @schollex ?


@AlexV Thanks for the hint, but this will not work in my installation.

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schollex avatar image schollex jetlag commented ·

I read about CCL not being applied within the forum - perhaps it was this post.

See the DVCC-documentation chapter 11.4.1:

6. DVCC charge current limits are not applied to DC MPPTs when ESS is enabled with Allow DC MPPT to export. This is to get maximum output from the solar panels for export.


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jetlag avatar image jetlag schollex commented ·

Thanks @schollex . Now this makes sense again. I have ESS running, but DC excess AC export is not activated. That's why CCL is limiting also for my MPPT.

I will active the DC excess AC export and check again... unfortunately this needs to wait a few days as the weather is only a few amps outside today. ;-)


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schollex avatar image schollex jetlag commented ·
I tested this. When I disable export of exceeding PV, my CCL = 0 does affect my MPPTs => they are throttled to 0 W like you observed.
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kevgermany avatar image kevgermany ♦♦ jetlag commented ·
DVCC does control the MPPTs to restrict charge current. But if there are DC loads, these are extra and will also be serviced.
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