question

I have a Multiplus Compact and it makes little noise unless it's bulk charging the batteries or if the inverter is supplying 1000 watts or more.

The fan runs only when necessary, again when the inverter/charger is working hard.

Hi

I was also a litte bit shocked how loud they can be. The hum comes from the transformer inside the multi, and some level of it is quite normal.

In my case i can hear the state of the grid connected to it. During the night, when there is no load on the grid, the multis are quite silent, but during the day there is a constant changing hum. This comes from distortion in the grid, that resonate in the transformer.

When i disconnect the grid and there are no loads, i can hear just a little bit of hum.

Does your noise change when you disconnect the grid?

Hi,

thanks for the comments. I do not think it's a problem of distortion in the grid, because distortions would not lead to the 50Hz hum that I experience. I have not tried to disconnect the grid.

However it changes quite a lot with load (not to mention the fan).

I talked to somebody who owns a SMA Sunny Island 3000, which he very rarely hears. Both inverters should be the same concept, with transformers, but as SMA is very tight on how to contro their stuff or even read data that is not an option.

I'm still wondering if I'm doing something wrong. Right now the MP2 is running at 250Watt, and I can hear it from 2 stories up with doors open, probably 10m away. I can not imagine having this in a RV or on a yacht. I'm a sailor myself and having that noise on the boat would certainly not encourage a good nights sleep...

I'm not talking about full power, it's more like idle...

Since last week I have also a Multiplus II running and it make big noisings. ca 60 dB. Not every time, but the hole day. Nothink changing , if I switch off the grid.

How can I see the fan for locking, may be to change the fan ?

Best regards for Spain Udo

Yep, mine is a noisy bugger. Lucky it’s in a shed.

I always place big rubber rings or pads between the mounting plate and the wall with my customers,
that helps considerably.
Also in the left and right bottom corner between the wall I mounted these rubber rings.
(I total 5 rings with a Multiplus 2)

This way the inverter does not resonate to the wall.
Of course, it continues to cool (fan) at medium powers.
The difference is significant!

I’m concerned to see this. I’ve yet to install my MP II but the area on my 5th wheel is right below the bedroom. Is it possible to remain connected to shore power, whether 30 or 50A and shut off the MP II? At night, it would not need to do any work and I’m hoping to just shut it off with the digital control panel. Would it still pass power to the trailer?

@IAE Have same issue with my Multiplus II 48 5000.

I ask an installer to look at it and he says that the fan noise and hum out of my Mutliplus II is normal for this model.

Still the fan noise is loud and the housing is amplifying it. My wife ask me if this is also a generator.

One valid option for me is to return or sell the MP2 and buy the old model.

Second option it should be to replace the fan with a quiet one but with same air flow preferable with damping. In this case I think i will loose the warranty. MP2 being a relative not a mature product i will not recommend this option.

Have same issue with my Multiplus II 48 5000.

I updated in feb 2022, it did not make any difference.

Quality of victron is very disappointing, I would say: rubbish.

We live in 2022, this annoying 50Hz buzz is from an old tubelight from the 1940s

Wished I did buy some other brand.

Wow, what a noisy unit the MP2 (48/3000/35-32) is !

Just got mine running this weekend, in ESS mode with Pylontech batteries.

The hum is amazingly loud, once power exceeds 1kW.

But once the fan starts running, all hell breaks lose.
It sounds like a 40 year old bathroom exhaust fan on its last legs.

Updated firmware from 490 to 497, no change.

I'm installing this in an outbuilding, hoping it won't bother my neighbor.

But installing this unit in an RV or boat, is an absolute NO !

Now this is my first experience with Victron, and I love the community support and the Open-Source approach (Venus Pi3, etc), and the features of the MP2.

But that noise! Come on Victron, you can do better!

Cheers

heleb

Yep my MP 2 make humming noise, it’s fitted in my garage which is also my office and it’s annoying as the bedroom is just above it, in the dead of the night I can hear the humming. To say I’m sli disappointed with it.

on the other Hand my older multiplus on the boat is almost silent.

when people ask about the set up because they would like one, I pre warn Them about Where to fit it because of the noise.

the unit resonates against the wall!
get 3 large rubber washers between the unit and the bracket and 2 rubber washers between the bottom screws.
day and night difference!

Having the same issue with resonating against the wall. Audible from the adjacent room and even multiple stories up. Just ordered myself a few of these, lets see how this goes

Here is what I did to successfully stop the MP2 5000 spreading the noise in the entire house. The MP2 was hanging directly mounted to a wall in the basement.

I attacked only the structure-borne noise of the MP2 by decoupling it from the wall.

In the hardware shop, I bought a damping mat used normally to be put unter washing machines and cut it to the size of the MP2 back side.

I bought special sound insulated dowels. Three for the mounting plate holes and two for the bottom corner holes of the MP2. The german expression for the pegs is: "Fixotec Schallschutzdübel Nennweite 12".

I drilled five holes mit 12mm diameter and about 50mm deep into the wall, as well at the corresponding position of the damping mat.

I put the pegs into the drilled holes. Then I positioned the mat at the wall, fixed the metal plate of the MP2 on top of the mat and fixed it with three screws.

Since the mat is very firm, the plat sits pretty solid and it can carry even the heavy MP2 5000. Of course, you need a solid wall for the plugs.

Currently, my MP2 is held only by the plate with the three screws. With the two bottom holes, I will secure the MP2 absolute safe, after my installation is finished.

The result:
Even if the MP2 operates at high power, there is no more noise to be heard in the other parts of the house. Only if the door of the power room in the basement is open, the acoustic sound is spread.

Conclusion:
With a minor investment (18€ for 10 pegs 12mm and 15€ for the mat) and a bit of labour – the "heavy" lifting the MP2 – I am a happy camper.
All, without touching the MP2, replacing the fans and modifying the control ciruit

I try to add some fotos to show the setup and the used dowels.

Cheers, Herb

In case anyone has missed it. A free retrofit cure for the excessive fan noise.

https://community.victronenergy.com/questions/108663/victron-multiplus-ii-noise-level-what-is-your-expe.html (Scroll down to the bottom for Guy's post)

https://www.dropbox.com/s/3cvyf66h9j1eigq/2023-02%20-%20MPII%20Retrofit%20kit%20to%20reduce%20low%20RPM%20fan%20noise%20v1.pdf?dl=0

I have a MultiPlus II 48/5000/70-50 HQ2237 firmware v498 mounted to a brick wall in the garage. Our bedroom is directly above and unfortunately the hum travels up the wall, resonates and amplified into the bedroom.

A solution like the one above, isolating the unit from the wall looked ideal. I'm in the UK and had a lot of trouble sourcing the sound insulated dowels.

However, I discovered Rawlplug have something similar called FLEXI-PLUGS which are available at ScrewFix. https://www.screwfix.com/p/rawlplug-rawlnut-flexi-plugs-m5-x-40mm-50-pack/743kf

The plugs have a metal thread at the bottom end which pulls the plug towards the unit, compressing it and causing the rubber to bulge and fill the hole. These screws are fine for the main bracket, however a longer screw is needed for the bottom two holes. Especially if installing a mat between the wall and the unit. https://www.screwfix.com/p/easyfix-bright-zinc-plated-roofing-bolts-m5-x-50mm-10-pack/8754j

For the mat, I used one of these cut to size https://www.screwfix.com/p/mottez-shock-absorbing-floor-mat-grey-blue-620-x-620mm/1374v

With this solution, the noise has been greatly reduced but I hoped it would prevent the hum completely. I have a newer model which already has the fan noise fix on the PCB. When the fan was at full speed I was able to hear it. This solution has fixed fan noise! I can no longer hear the fan when under high loads, either charging or discharging.

I can still hear the hum but it's greatly reduced, I'd say it's removed the low frequency pounding and softened the higher frequency hum. I used to hear the hum when discharging at 1500W, now I can't hear it at all. But I can still hear hum at anything more than 1500W.

UPDATE: I thought this had fixed the fan noise but I'm not sure now. I need to investigate further but I think it's the fan I can now hear and not the hum. It still wakes me up when charging from the grid overnight.

UPDATE 2: After more testing it's definitely the inverter hum I can hear. I don't hear the fan noise at all any more.

Aside from this, the unit is an exceptional piece of kit, especially when combined with a DC charge controller and a Fronius inverter on AC Out. It makes for an incredibly capable and versatile system.

A couple of images of the main bracket attached to the plugs through the mat. Initially I tried the mat solution as I couldn't find the plugs. It did make a difference but the plugs help even more. I found it was easier to assemble the bracket with plugs before inserting into the wall and tightening.

I do confirm that adding the mat behind the multi has changed the game. Absolutely no noise transmited via walls!

https://www.hornbach.de/p/waschmaschinenunterlage-60x60x1-5-cm-antirutschmatte-antivibrationsmatte/4063923/