You forgot the fact that he already said that the power draw is minimal… (Point 1).
…when the grid is enabled, regardless of whether there are consumers or not.
So happens even when no draw from DC, therefore no power assist…
Just thinking … Perhaps the effect is the other way round.
The current location is closer to the transformer than the alternative location. The loop value may be much worse at the other test location and therefore the effect is not as noticeable here.
Hi @Netrange ,
The battery is in an idle state in the video. It charges at night from 11 PM to 7 AM (cheaper tariff) based on the schedule and discharges during the day to 50% (minimum SOC unless the grid fails).
You didn’t take the battery with you to the other tests/connection points, did you?
The battery was not tested in another location/inverter; it’s too heavy)
Hi @Christian82,
I tested the inverter in “dumb” mode by setting the grid code to “None,” disabling UPS, removing the ESS assistant, and disconnecting the inverter from the Cerbo GX.
Unfortunately, I got the same result (hum noise), regardless of whether there were consumers or not.
Hi @alexpescaru,
Unfortunately, changing the “Grid setpoint” parameter from 70–1000W did not yield any results. The noise was slightly modified after 400+W but is still present.
Hi @lxonline ,
In my opinion, the noise issue is not related to the AC/DC cables, but I will replace them as recommended by Victron.
When upgrading the AC cables from 6 mm² (max 50A) to 10 mm² (max 80A), should I replace only AC IN, or should I replace AC OUT 1 as well?
Additionally, I will add another DC cable (50 mm²), resulting in 2 x 50 mm² (2 x 215A = 430A max).
Thank you very much, everyone, for the advice.
Additionally, I’m planning to file a complaint with the electricity grid company to request a grid quality check. Hopefully, they can identify and resolve any issues on their side.
You could ask to switch phases as well? (Edit: i saw you had tested then all) Usually harmonics 3 5 7 come from noisey consumers - inclusing solar systems)
If the grid is in as much disarray dues to circumstances you may find there is too much load on that one phase.
AC in is based on your grid charging needs, but looking at how weak it is (voltage all over the place, you wont be able to draw much current anyway.) {looks much like ours but we don’t have war for an excuse.}
Our general work around is to actually have an inverter dedicated to grid charging. (Charging triggered when needed)
The inverter system inverting 24/7 for total separation.
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As a further thought is your grid neutral ok?
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@lxonline ,
No, it looks like the incoming grid-neutral is in poor condition.
Today, my neighbor and I had a conversation with an engineer from the electricity company. We explained our issue and the steps we took during troubleshooting process. He suggested that the root cause of the problem might be the grid-neutral and proposed connecting the ground cable to the Victron AC1-IN neutral for testing. Since our houses have a TT grounding system, this was easy to implement.
We performed the test on my neighbor’s system, and the result shocked us—the noise was gone, and there was complete silence in bypass mode with consumers!
Unfortunately, my system failed the same test 
. I suppose it might be due to poor grounding. I’ll try to rent a device to check my ground resistance and fix it.
I feel we’re on the right track to resolving this issue! 
So, is it OK for the Victron inverter to have “ground” as neutral in AC-IN till we resolve the issue with the grid company?
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Excellent.
Somebody winning 
Our neutral and earth are bonded here in our local distribution board in the home network. It may be worth an experiment. Conform you have your earthing rods near the incoming DB board?
Some points to look for (or get your grid provider to do) to possibly improve the grid side are to check for corrosion on joints and connections on the main lines. Sometimes they just need a clean up.
Resistance is the key in all circuits.
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Yes,
We have a general distribution board for eight houses without earthing rods.
Each house has individual earthing rods connected to its own internal distribution board.
I don’t know that the victron will accept incoming grid if the one connection is not a conductor.
Usually it needs line and neutral.
And the rod in TT is not connected to any conductors? Not a set up I am familiar with.
I do know noise increases with high impedance sources and if your grid has high impedance it won’t be helping.
Unfortunately, I don’t know, I’m not an expert in that area.
Good evening,
Maybe this is happening?
I see/hear this fenomena when in the street a neighbour uses a brushed motor, like a drilling machine, table saw, etc, while I’m taking power from the net to charge my battery.
When I switch off the grid and run solely on the inverter, I hear nothing, when I then use at home a drilling machine, I have it back again.
It’s just that these brushed motors are not running perfectly, and then you see these strange frequencies, the inverter controls try to compensate rapitely, creating a humming sound.
Can that be the issue?
Easy to test, right?
Regards, Jeroen.
I have the same experience, my Multiplus can have a little hum or a louder hum in the same mode. Disconnecting from grid turns the loud hum into a little hum immediately. The hum varies throughout the day. Now I can even hear it suddenly in my bedroom while 15 minutes ago I heard nothing. Nothing did change in the meantime. Dess is active but idle, so no charging or discharging, now and also not 15 minutes before.
Changing load by turning on 3kW of dump terras heaters with a powerfactor of 1 does affect the hum for a few seconds because the victron does some kind of peak shaving which I don’t use but which can’t be disabled above minimum soc.
I installed 5 dampeners between the multiplus and the wall and the hum is almost gone outside the room where the multiplus is installed, only on high load it is noticeable.
M6 30x30:
https://a.aliexpress.com/_ExBxOY8
I use those noise cancelling mounts originally designed for sanitary installaions…
On the lower side, I put a rubber matt between wall and MP2.
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I saw them, but I thought the dampening with rubbers outside the wall would have better result than using the inwall dampeners. But as I can’t compare I don’t know it for sure.
Either way it is quiet enough now, next step is disabling internal fan and using 2 fans on a mount in the bottom.
Just remember the system will derate with the internal fans disabled, that there is external cooling won’t matter.
That’s a pitty. I still think my fan of the victron is generating an extreme noise. It is not the sound of blowing but the sound of howling.
A friend of my install their victron in the following weeks and if that unit doesn’t howl I will contact the supplier about the issue, otherwise it’s a product behavior and I have to disable the internal fan and use external ones.
I saw a YouTube video that the derating is just a bit when using external fans.