ESS not working as expected with “Invert only”

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solarlion asked Jun 16, '22

ESS not working as expected with “Invert only”

Hi,

I Have 3 Multiplus II 5000 in 3 phase configuration with Pylontech US3000C Batteries. There is an old AC (in) side coupled Solar system and an a new DC Coupled with two Victron MPPTs. For legal reasons, Im not allowed to feed to the grid with the Victron system (Zero feed in). But the old Solar system is allowed to feed in.

ESS normally works as expected.
In the Morning the Batteries Charge with the chargers in the Multiplus and the MPTTS. When the Batteries are full, the old AC Solar system feed to the grid and the new Victron MPPTs go down to Zero. This happens at around launch time.

Because there is more than enough solar to charge the Batteries with the DC MPPTs, my intend was/is to disable the chargers in the multiplus and allow the old solar system to feed the grid starting in the morning. So I go to the settings -> “Virtual Switch” (Umschalter) -> and to “Inverter only” (Nur Wechselrichter). First everything looked good, the chargers disable and loading only happen with the MPPTs. But then the Problem: The Inverters/ESS do not feed anything in the evening. Its like the whole Inverters are just off and also not providing energy.

So I think this is a bug in ESS?
How to disable the chargers and keep the rest of the ESS functionality active?

I Thought this is “ESS Mode 2” where I can override this settings as described here:
https://www.victronenergy.com/live/ess:ess_mode_2_and_3
Or is it necessary to enable this “ESS Mode 2” somewhere?

Multiplus-II ESS

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Answer 1 · 2022-06-16T06:01:33Z

nickdb answered · Jun 16, 2022 at 06:01 AM

I doubt ESS can work like that. Loads have to be “buffered” by the battery system, So when a load reduces it needs to briefly send surplus power to the battery while it manages grid/PV supply.

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Answer 2 · 2022-06-16T06:07:51Z

mondeoman answered · Jun 16, 2022 at 06:07 AM

Where are the loads connected (AC IN vs. AC OUT side)?

Do you have a Victron Smart Meter somewhere on the AC IN side?

ESS feed-in can be easily disabled. If you really want to ensure that it does not charge from the AC side, you could move the AC PV inverter upstream from the Victron SmartMeter, like in the picture below. Then the Victron ESS will never see any surplus on the AC IN side.

wiring.jpg (61.6 KiB)

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solarlion commented · Jun 16, 2022 at 06:28 AM

Thank you for this idea.

Yes I have an EM24 installed. Good idea what you draw, but I want to have this controllable. Switch the charger on in winter time when I need every litte Watt for loading and off in summertime to have more feed in. So it needs to be software controlled somehow a switch and not a hard wireing.

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mondeoman solarlion commented · Jun 16, 2022 at 11:58 AM

The setting of (Umschalter) is ignored in ESS Mode.

You could make a hardware switch to move your AC inverter upstream or downstream from the Victron Smart Meter like in the attached wiring diagram.

E.g. search for SPAMEL SPMP\4P40 . It is a two-way selector (A - 0 - B) and has 4 poles each way.

Or you could do it with two interlocking contactors, like they use on Automatic Transfer Switches for Power Outage Backup Generators.

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wiring-2.jpg (64.4 KiB)

solarlion mondeoman commented · Jun 16, 2022 at 01:46 PM

Thank you. Yes a possible solution.

Still hope to find an answer why it is not working as described in the manual. And why it shuts completely off when set to "inverter only". Assumption is, that the GUI presented button is another "switch" as the Modus TPC Register, even if both do exactly the same...

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Answer 3 · 2022-06-16T06:25:02Z

solarlion answered · Jun 16, 2022 at 06:25 AM

Thank you for the Answers.
Yes, I have an EM24 Ethernet. And its working to regulate this to 0 as long as I keep the setting on “ON”. But when I switch the setting to “Inverter only”, ESS does not supply any power. Its just like the whole system is switched off.

And Sometimes, I want to use the Charger – when there is not enough solar from the DC MPPTs to charge the batteries during the day (Winter time) according to weather precast. I only want to disable chargers in the summer, when there is way to much solar and much of it is wasted.

I want to use what is described in the manual in Chapter 2.1.b
https://www.victronenergy.com/live/ess:ess_mode_2_and_3

But this is not working. When I set to “Inverter only” everything is off, not only the charger.

Is this not possible with the Settings-GUI and only working by using Modbus-TCP?

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Answer 4 · 2022-08-29T21:46:21Z

theoschipper answered · Aug 29, 2022 at 09:46 PM

Hi, when you select "Invertor only" does it supply power to your critical loads?
If so, I think the system works correctly, it disconnects itself from the grid and ESS will stop working.

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Answer 5 · 2022-08-30T11:02:32Z

mlapp answered · Aug 30, 2022 at 11:02 AM

Ich nutze auch den Softswitch und schalte den MP2 auf "Inverter only" (2) wenn der Akku 98% SoC erreicht hat. Allerdings schalte ich auch wieder auf "On" (3), wenn mehr als 10 Sekunden mindestens 150W aus dem Netz gezogen werden. Zusätzlich hab ich noch einen Schutz programmiert, der Umschalten nur alle 5 Minuten erlaubt.

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solarlion commented · Sep 19, 2022 at 06:28 AM

Welchen Modbus/MQTT Pfad verwenden Sie für die Umschaltung? Es scheint als reagieren die verschiedenen Pfade hier unterschiedlich?

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