question

Nicholas Wessels avatar image
Nicholas Wessels asked

Multiplus II shuts down immediately on grid failure

We have a system setup as follows:

Multiplus II 48/5000/70-50 firmware version: 469

CCGX running ESS firmware version v2.42

BMV-700
Grid Meter
MPPT 150/70

Everything running latest firmware.

We only recently upgraded from a Multiplus 3000 which we ran for more than 5 years, all settings have remained the same on the new Multiplus II in terms of the ESS settings etc.

We are having a strange issue which we are struggling to diagnose. When there is a grid failure (load shedding as it is euphamstically called in South Africa) the Multiplus II immediately shuts down and turns off. Plunging us into darkness like the rest of the country.

Battery voltage according to the BMV and CCGX is still more than ample at above 50v when this happens. Loads on the Multi are under 800w.

If I then go and use the manual switch on the bottom right of the multi, I can turn it off and on again and it will go on for less than a minute and then shut completely off again.

If I unplug the ethernet cable that runs from the VE.Bus on the multi to the CCGX, the Multi starts again and runs perfectly in inverter mode and powers the load during the load shedding. As soon as I reconnect the cable to the VE.Bus port on the multi, it immediately shuts down again.

No error reports, no alarms.

This leads us to believe this is some type of communications issue between the multi and the CCGX.

I dont believe there is anything wrong with this cable as it worked 100% for more than 5 years between the Multi and the CCGX and it also works 100% when the grid is on.

If there is NO grid failure, the Multiplus II runs happily for days on ESS settings using the generated PV power to supplement house loads etc.

This issue ONLY happens when the grid fails.

Has anyone seen this issue before? The site has been on the VRM for many years if anyone from Victron wants to connect and check it out.

Multiplus-IIESSCCGX Color Control
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Murray van Graan avatar image Murray van Graan commented ·

Have you tried rolling the firmware back to 465? I would give it a shot

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reed avatar image reed commented ·

Hello. Did you come right. Version 478 is working wonders. Please try and upload thd multiplus 2 to version 478

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Nicholas Wessels avatar image Nicholas Wessels reed commented ·

This was a year ago. Gave up and swopped out the unit for a Multiplus.

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

Hi @Nicholas Wessels

I'd first check in the CCGX if the unit is not set to 'charger only' because that would cause this behavior.

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Nicholas Wessels avatar image
Nicholas Wessels answered ·

Hi @Daniël Boekel (Victron Energy Staff), unfortunately not it. It is set to "On".

See below:


1580476664738.png (27.8 KiB)
1580476707673.png (44.1 KiB)
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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Ok, and what does it say there when the grid fails? and are there alarms active when grid fails?

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

Hi @Nicholas Wessels

Ok, I've looked at your system, first some questions:

-you've configured the battery as 215 Ah, but are using 'tubular plate traction battery' settings, are you sure this is correct?

-deepest discharge on the BMV is 75 Ah, if the batteries are / were 215 Ah, they're not anymore

-the shutdowns were caused by low battery (settings)

-I don't know what type of batteries are connected, but most 215 Ah batteries don't like it when 80 A is pulled from them

-DC voltage wildly fluctuates between 58 an 47 volts.

This all leads me to think the batteries are defective / not capable enough for this system.


shutting down on grid failure (while connected to CCGX): sorry, I have no clue yet...

to reduce the wear on the battery, and see if the system reacts more normal, I'd first try to set ESS to 'keep batteries charged' and then simulate a grid failure.


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Nicholas Wessels avatar image Nicholas Wessels commented ·

@Daniël Boekel (Victron Energy Staff)

Thanks for the above, to answer a few of your questions:

1. Batteries are 215ah. Deepest discharge, that is because we try to never run the batteries down below 20%.

2. System should not be pulling 80A from these batteries, we will have to adjust the ESS settings to stop that from happening.

3. The shutdowns are not caused by low battery. In fact the system is now running for the last 1.5 hours off batteries, with the CCGX disconnected as we currently have a grid failure.

Battery voltage right now is sitting on 54v and 100% SOC. If I were to plug the CCGX in right now, the Inverter would still shut down.

4. 90% of the time when there is a grid failure it is during the day when we are producing over 3kw of PV and using under 800w of load yet the inverter will only shut down when the CCGX is connected.

So to summarize, low battery voltage on the batteries is not even coming into play here when the inverter shuts down.

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