Multiplus II ESS problem after 6 months is inverter mode

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duto69 asked Sep 16, '22

Multiplus II ESS problem after 6 months is inverter mode

Hi,

Since 1.4.2022 I was in island mode by setting multiplus to inverter mode.

13.9.2022 I switch multiplus from inverter to ON and system not working propertly

Before 1.4.2022 I use ESS whitout any problem more than 2 years.

System looks like don't know what to do and is confused. He floating between feeding to grit (this is not allowed) and charge from grid.

https://www.youtube.com/watch?v=vNwizu5_O5k

I am completely at a loss what happen.

I upgraded firmware multiplus II

I reset all and setup as new.

I try ET340 change for ET112

I try run only one mutliplus (no parallel)

When I setup in ESS grid metering inverter/charger, system start charging battery despite is not discharge below ess threshold and gradually stop using solar energy

When I setup in ESS grid meter external meter, system looks like in video.

What I noticed on the multiplus II don't show input current, but show input power

System

My system is:

2 x Multiplus II in parallel

ET340

1 x MTTP 250/100

1 x MTTP 250/100 ve.can

BMV-712

CCGX

MultiPlus Quattro Inverter Charger ESS

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Modifications Space

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Answer 1 · 2022-09-16T08:00:32Z

marekp answered · Sep 16, 2022 at 08:00 AM

@Duto69

Is your system single phase?

What type battery you have?

Why Minimum SOC you have set to 90%?

I observed that "battery life" works up to 85% SOC but my minimum SOC is set to 20%.

When "Active SOC limit" gets set to 90% battery there will be not much use of battery by the system.

You have the ET340 but in your setup you have "grid mettering" done by "inverter/charger", why?

This zero current on AC-in can be caused by faulty CT socket on MP-II.

Try to clean this socket by plugging and unplugging 3.5mm plug in to the CT socket couple of times.

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Answer 2 · 2022-09-16T08:19:23Z

duto69 answered · Sep 16, 2022 at 08:19 AM

Yes, system is single phase

battery is AGM

SOC 90% because better life span

When I use ET340 system is totaly unstable, see in video

MP-II have internal CT

I don;t have external CT

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Answer 3 · 2022-09-16T08:30:31Z

marekp answered · Sep 16, 2022 at 08:30 AM

@Duto69

If this is single phase system, why did you install ET340 and not ET112?

There is no point of using "battery life" if the "Minimum SOC" is set to 90%.

System could be unstable when unused CT socket in MP-II is faulty.

When this happens the internal CT is disconnected and system does not know how to calculate power flow through MP-II and all kinds of weird things happen.

New MP-II design does not have this round CT socket anymore. They use terminals now.

(what video you want me to see?)

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Answer 4 · 2022-09-16T09:54:23Z

duto69 answered · Sep 16, 2022 at 09:54 AM

Fault found, internal CT not work, thats all...

If I cancel parallel system, one multis work, second not.

That the reason, why in inverter mode work everything fine.

But I suppose, when I have external grid meter, internal is not use...

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marekp commented · Sep 16, 2022 at 10:42 AM

@Duto69

Even if you use external Power meter, internal CT is also used to calculate AC loads and Critical loads.

The internal CT is not used only when you plug external CT into the socket.

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