Lindsay avatar image
Lindsay asked

3-phs machine switching OFF when ESS switches to battery+inverter when grid fails?

One of the best ability the inverters has is to switch off very quick when grid fails, that it's unnoticeable to the loads.

However when our 3-phs MP-ll inverter is connected to the 3-phs machine load, when grid fails it switches off and we have to manually switch it (3-phs machine load) back on again. We have tested with a PC and when grid fails and switches over to inverter the PCs stays on.

Is it because one is a 3-phs and the other a single phase or there's something I'm missing?

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Alexandra avatar image Alexandra ♦ commented ·

If the system itself is not switching off, then it may be a protection circuit on your 3 phase device.

Ithe three phase device may be detecting a sudden voltage or frequency change and then shuttting down in protection.

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Lindsay avatar image Lindsay Alexandra ♦ commented ·
@Alexandra Thank you. The system it's self is not switching off, it's just the 3-phs machine(load)

Is there anyway I can rectify this and stop it from occurring?

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Alexandra avatar image Alexandra ♦ Lindsay commented ·

Are there any electronic controls of thebthree phase load? What load is it? Some pump controls like i said previously detect voltage drop (brownout condition) and then disconnect on protection.

W hat is your AC low cut off before disconnect and are you using a grid code at all and LOM detection?

If it is not a battery related issue as @nickdb mentioned then it could be the disconnect voltage.

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Lindsay avatar image Lindsay Alexandra ♦ commented ·


The load is:

Re-Flow Oven (please not it tends to draw a lot on startup)

Make: DIMA

Model: SMRO-0253

Yes it has a controller.

when we switch it on (on gride) it works fine but when grid fails and the inverter kicks on it switches off and we have to manually switch it back on.

After switching it on (while inverting) it works fine but when grid comes back on this time however it does not switch off as it goes on grid it continues

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1 Answer
nickdb avatar image
nickdb answered ·

What is the load? Do you have any vrm charts from when it is running normally?

What alarms/alerts is the system logging on VRM or on the GX?

This has not been uncommon with some systems using freedom won batteries, often traced back to the battery being incapable of meeting the surge in demand when transitioning from grid, and where the inverter size is larger than that recommended by the manufacturer.

Please confirm what your battery setup is.

Some detailed (zoomed in) vrm charts covering this event showing battery voltage, current, soc and min/max cell voltages as well as AC voltage and AC loads would be helpful.

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Lindsay avatar image Lindsay commented ·

@nickdb Thank you

The load is:

Re-Flow Oven (Please note it draws a lot on startup)

Make: DIMA

Model: SMRO-0253

When it’s on grid:


There is no alarm


The Battery Setup:


connected to a 3-phs with 5KVA victron inverters

When grid is off and it’s inverting:

The only alarm that shows up is that the grid is lost






I hope these are all the charts you needed.

Around 08:36-39 is when we switched over to inverting

EDIT: when we switch it back to grid the machine (load) does not switch off it stays on.

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nickdb avatar image nickdb ♦♦ Lindsay commented ·

so, min/max voltages are fine for cells.

Is your battery getting to 100% SOC? this snapshot only seems to show around 95%?

Have you double checked your ESS cutoff voltages in the assistant?

VRM is unfortunately not very granular, so it can miss the detail in that specific moment.

This sort of complaint has been a bit too common in systems with some FW batteries.

It is possible that in grid transition that the battery is just overwhelmed causing the loss of power. If you had an overload (from surge loads) you would expect the GX/inverter to log it.

Since this can be reproduced, what you can try is to connect to the multis with a mk3 and ve configure, use the VE bus monitor which should show realtime detail like ripple etc.

Reproduce the problem and see if the monitor gives any clues why.


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Lindsay avatar image Lindsay nickdb ♦♦ commented ·

Good day, we had decided to just let it be and switch on the load manually whenever there's a switch over to the battery.

However last Friday we left the battery about 95% and AC IN was connected with the system on and there was hardly any loads connected to it. Today Monday morning we came in and the DB from the grid in our factory had tripped after checking the system the battery had tripped but, the RCD and CB had not tripped.

On VRM portal it shows that the battery was around 90% but on alarms it kept saying low battery and it tripped Friday just before midnight, which does not make sense. Do you perhaps know what's causing this?

Please note we are currently experiencing 2hr period loadshedding between 1-3 times max. I'm not sure if that is playing a part cause after all it's suppose to be able to do that.

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nickdb avatar image nickdb ♦♦ Lindsay commented ·

If the battery has tripped then there is an issue. Log a ticket with Freedom won and have them check the BMS error log.

If the battery trips then low voltage is what the inverters will report.

Sounds like the BMS got emotional and probably shut off.

You can download the bms utility here: BETA

Attach the USB cable supplied with the battery to a windows laptop and run this.

iirc it should permit you to see the error log when you connect.


To add. Please check all your wiring and connections thoroughly. That’s the first thing battery manufacturers like to blame.

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