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zwitter avatar image
zwitter asked

Multiplus wont invert.

I have a Multiplus 5000/24/120. 2x MPPT, BMV700, 400Ah Lipo4, CCGX.

the system has been working in ESS for several years no problem. Then about 8 weeks ago one night the house went black. I found the 25A breaker rhat feeds the Multi grid power tripped. I reset it and it stayed set but no power to the house. Since then the inverter just wont start.

I took the Multiplus to a victron certified repairer and they said nothing wrong.

I reinstalled and found batteries were out of balance so reballanced, installed a new BMS and still the inverter wont invert.

I have reloaded the config but made no difference.


I have run out of ideas. It should work but wont.

the multiplus just stays in bypass. I called an electrician who said he was an expert and he told me the inverter output was dead short!

any ideas, suggestions?

thank you in advance.


james

multiplus ve.bus
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klim8skeptic avatar image klim8skeptic ♦ commented ·

@Zwitter I called an electrician who said he was an expert and he told me the inverter output was dead short!

The output of the multi will appear as a dead short if measured with a multimeter. The output is connected to the transformer after all.

You might want to look a bit deeper.

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3 Answers
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derrick thomas answered ·

I would start by isolating the inverter from the ac in and out. Will it go into invert mode with the ac in/out isolated? If so then connect the ac out put and test, then the ac input and test. One step at a time, you need to isolate the problem.

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zwitter avatar image zwitter commented ·
Ok I have done this and posted the findings. Now what?
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zwitter avatar image
zwitter answered ·

Ok,

I went and did some more testing.

the Multiplus goes into invert mode when the AC in is switched off. It then appears to be happy until the battery runs out.

when the AC is turned back on it drops out of inverting in about 15 seconds.

the system is designed to be an ESS. So the batteries are just to spread the solar power into the night each day. It saves a lot of power bills this way.

so where do I goto now?

I did take the Multiplus to a certified repair centre and they said nothing wrong with it. I doubt they did or even can test the logic part of the unit.

so I need some suggestions as to where to take it for a better repair or what I can do to take this further?

I did reload the setup from backup but no change.

thanks James

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ejrossouw avatar image ejrossouw commented ·

@Zwitter This will take time and patience to investigate and will be a challenge via a forum. I suggest also changing the breaker, check the internal fuse of the inverter and look at the VRM records to try and understand why it happened. Check the error VRM log for sync or ground relay errors. Check the grid code settings and measure input / output voltages to ensure they are within the required limits as others also suggested. I wonder whether the ESS not longer can see the required input energy meter data it requires to allow inverting and stops as when contact is lost with an external energy meter. You can maybe test this borrowing an external current sensor from the service centre. Lots to investigate and think about. Good luck.

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zwitter avatar image zwitter ejrossouw commented ·
All breakers check out ok.

I don’t know about internal fuse but the inverter detects AC in fine and the output works too.

VRM just shows the system turns off. No actual errors recorded.

grid codes are fine. We actually have an external box that verifies the voltage and frequency settings are good.

the power meter is connected and working ok.

I suspect it is a logic error around the Virtual Switch?

who are the experts in Australia able to fix this?

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ejrossouw avatar image ejrossouw zwitter commented ·

Have a look here and also maybe reset the inverter, reinstall the firmware and reinstall the ess assistant.

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zwitter avatar image zwitter ejrossouw commented ·
I have reset the inverter. Well turned it off, disconnected then reconnected and turned on. Also reset from CCGX.

have reinstalled the firmware and config. Reloaded the software ESS, checked all settings, VS etc.

I checked your link but it does not list their skills. So far have spent $700 and got nowhere. The spaky told me the output was a dead short. It is a transformer so probably right but unhelpful. And the repair centre (victron approved) said it does invert. Which it does but they did not check any of the software options and virtual switch etc, ESS etc.

the next option os to get another Multiplus and prove it works. But still nobody seems to know how to test these things properly.

james

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nickdb avatar image nickdb ♦♦ zwitter commented ·

Any authorised center has test processes. These are available to you as an end-user to do yourself, if you have the tools and ability.

https://www.victronenergy.com/media/pg/Pre-RMA_Bench_Test_Instructions/en/index-en.html

They will test the core functionality/HW, they won't test customisations that can affect behaviour.

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Rob Fijn avatar image
Rob Fijn answered ·

Maybe try one more test.
Disconnect all wires of the AC output of the MultiPlus ( line and Neutral)
Switch ON and the unit will invert, right ?
Then switch ON the AC_in... does the unit now keep inverting correctly ?

If yes, then you have a loop connection at the AC-out to the AC-in, somewhere in your electrical installation.

Let us know how this goes.


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