question

Bobby avatar image
Bobby asked

Victron Multiplus II 48/5000 (noisy) Fan Replacement

Hi all, as per the topic, I own Multiplus II 48/5000/70, with MPPT and a 48V battery bank.

Things are working as expected, so no problems with configuration.

The Fan also switches on when having a load of around above 2kw for more then 30-40 seconds (and I also believe that that is in order). However - I am not confirmable with the noise of the actual fan - the thing is loud and I do know that there are many fans on the market that have different bearings in order to lower the noise.

Can anyone advise if the fan in question is 24V DC or 12V DC and confirm the dimensions (if I'm not mistaken, it should be 120x120x38mm)?

Thanks in advance

Bobby

Multiplus-II
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32 Answers
getacca avatar image
getacca answered ·
There are news from Victron regarding the fan issue.
2023-02-MPII-Retrofit-kit-to-reduce-low-RPM-fan-noise-v1.pdf

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1234enough avatar image 1234enough commented ·
Has anyone have this retrofit kit fitted and has it improved the fan noise?
1 Like 1 ·
ecoman avatar image ecoman 1234enough commented ·
Also, those who have installed it, which model is your inverter, and what is the noise difference? Ideally decibel readings before and after the kit.
1 Like 1 ·
Rob Duthie avatar image
Rob Duthie answered ·

Hi

Their fans are noisy in those units even from day 1, yes there are 120mmx38 and are 24v.

It's to do with the blade design etc to have a low noise fan, this fan might be middle of the road type? As i side note this is the company that has made capacitors for years, not fans.

They are ball bearing type. Brand Jamicon data sheet attached.JF1238-14.pdf

Regards

Rob D

NZ


jf1238-14.pdf (388.5 KiB)
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Bobby avatar image
Bobby answered ·

I will try and find some replacement with lower noise (db) and attempt to change it...
The noise of the factory fan is just too annoying and loud

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Bobby avatar image
Bobby answered ·

Ok, so I found a possible replacement(s)...I understand that it is less thick, but that is not that important as diameter and flow rate...
Noise however is significantly less.

Only thing I'm not sure is which exactly fan is inside of the Multi II ?


The replacements (Noctua Industrial 120mm)

Also, the connector PWM has four contacts but it can be modified to two only so that won't be an issue

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Rob Duthie avatar image Rob Duthie commented ·

Hi

You need 110CFM or 186 m3/h flow rate

Model in Multi is a JF1238B2HR-R

24v 110CFM 2800 RPM dBA 43.50

They have s similar sound rating. all depends on the fan blade design if you want quieter fan noise. slower rpm as well with the correct blade design.

There are many other known fan brand names out there.

NF-F12 industrialPPC-3000 PWM
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Bobby avatar image Bobby Rob Duthie commented ·

Thats exactly the brand i posted the screenshot for...

Not sure why it didn't show

Based on the db rating, they would generate the same noise level :(

I wonder it the pitch of the noise would be different

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Deon avatar image
Deon answered ·

I have an EasySolar 48V 5000VA and it is extremely noisy

With an uncalibrated phone based noise meter, my Easysolar measurements are:

1 - Silence - 20dB

2 - My workspace - 50dB (EasySolar fans at full speed)
5 meters from
the Easysolar

3 - 1m from blue encl. - 60dB (fans at full speed)
of the EasySolar

4 - Outside the encl. - 80dB (fans at full speed)
at hot air outlet


The current fan JF1238B2HR-R, gives a spec of 43.5dB, which means the position of fans in the blue enclosure is the noise generator. I have not opened the enclosure to understand the noise sources.

I need some advice - do I replace these fans, and will it affect the warranty?

The alternative is to have the Enclosure moved, and the associated costs and additional wiring.




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Nickus de Vos avatar image
Nickus de Vos answered ·

Not specific to Victron, but in general the perceived fan noise of equipment is mostly contributed by vibrations threw the chassis rather than the fan itself. I'll put some good money on those fans being a lot quieter if taken out of the inverters and measured in free space. Often you can get rubber mounting systems for fans which helps a lot, pads, washers, screws etc. A good fan manufacturer like Noctua should sell some of these accessories. Best I think will be to buy a bunch of accessories with a good replacement fan then open up the inverter and see what you can do in mounting the replacement fan with some rubber accessories. Often something simple like rubber mounting screws in place of metal or plastic can make a big difference, or just ensuring that the mounting screw doesn't touch any other part like the chassis or cover.

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stenis avatar image stenis commented ·

I tape a bitumen mat on the inside of the housing cover, this reduce the vibration quite a lot - easy and cheap solution :)

1 Like 1 ·
Pierre-Marie Baty avatar image
Pierre-Marie Baty answered ·

I'm resurrecting this old thread for other readers to share my experience.

I have a Multiplus-II GX and I too find that fan noise absolutely excessive. I have applied stenis' advice and had taped bitumen mat on the inside of the housing cover, to find out that it had only improved the problem marginally -- i.e. when you're in front on the device. The situation is not improved when, as in my case, the enclosure is hung on the wall (a *concrete* wall) that separates the house from the parking garage : it can be heard from everywhere in the house !

I too have searched for fans with similar characteristics and found none that would be allegedly quieter, at least on their datasheet.

The vibrations induced by the fan activity are just absurd ; even its neighbour the Fronius inverter saturated with solar power generates less than half of that noise.

Moreover, the problem has gotten significantly worse since I upgraded my MPII firmware from v470 to v490; with the old firmware, the fan would only kick in when the device was sending to or drawing power from the battery and stay quiet in passthrough mode - now it spins even in AC passthrough mode, when all the power on the output comes from the grid input ! This is ridiculous and infuriating.

In my opinion the last thing that would work, apart from moving the enclosure far away from the house which is unacceptable, would be to create a forced air duct, well fitted to the enclosure's air intakes, long enough to breathe air from the outside, and deport the fan all the way there.

I see no other solution, apart from enabling that "silence fan" configuration assistant which has the big drawback of reducing the inverter power.

This annoyance is, IMO, by far the #1 negative point of these devices, and if I had known they would be so noisy I probably wouldn't have bought one. Buyers beware.

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popnic avatar image
popnic answered ·

@Bobby I had a chance to compare different fans with same voltage, amperage, and size. The Jamicon model - thank you Rob for sharing - that is in MP2 was the one of the most powerful form air flow perspective. From noise perspective you can hear mainly the air flow from the Jamicon fan when it is supplied with DC or high freq PWM from 20 to 24V.

Unfortunately MP2 need a hi flow fan to cool down especially the transformer and also the MOSFET's and choke due to "redesign".

I visit a showroom to discuss the fan noise issue. @Deon similar measurement results. There one unit MP2 was with fan on and it was also loud. I convince a technician to remove the front panel and he did it. We were surprised about the difference. With the front cover off the noise was way less but when he put the cover back, the noise comes back at high level again.

If you change the fan i think that you will loose the warranty but if you still want to do it, in my opinion you have to address to:

- noise source - fan itself - change with a better one with same flow rate;

- fan speed control hardware - low frequency PWM - add a basic RC filter;

- mounting bracket - transmit vibration to the housing - add a damping material under it and between the screws and housing @Nickus de Vos Victron should consider your remarks.

- housing - being half empty it resonate like an acoustic guitar - here you have to be careful because also the housing has an important contribution to heat transfer. @stenis good ideea.

Having some experience in NVH from one of my previous job I can say that this kind of issues are not so easy to solve and has to be considered in the design phase which, unfortunately was not the case.

Good luck!

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iand avatar image iand commented ·
I don't understand why Victron don't use a continuously-variable-speed fan (temperature-controlled) like in PC coolers instead of simple on/off -- this wouldn't make any difference at high loads (say, over 60% of maximum power) but could make the units much quieter at medium loads (say, 20%-60%) where they spend most of their life. It's only the last part of the fan speed curve where the noise goes up rapidly, at medium speeds they're *much* quieter.


Any comment from Victron about why this is, and whether it could be added in future via a firmware update?


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Rob Duthie avatar image Rob Duthie iand commented ·

Hi iand

The fan speed is controlled depending on the temperture of the transformer and switching electronics.

One note when at lower speeds they are more noisy due the PWM controller.

Regards

Rob D

NZ


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kevgermany avatar image kevgermany ♦♦ Rob Duthie commented ·
Rob, I fitted Noctua PWM fans to cool my batteries. Tested before installing. They're completely inaudible until about 60%. So although older ones may be noisy at low speed, good ones aren't.
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Rob Duthie avatar image Rob Duthie kevgermany ♦♦ commented ·

Hi Kev

You say you fitted a Noctua PWM controlled fan in the multiplus and it is a lot quieter the orginal ones? what about airflow rating compared to the original ones. I see that they only do 24v ones in a industrial version. and very simalar air flow rates.

They are half the db noise rating of the Jamicon ones and also have included damping etc.

The fans that are mounted in the Multiplus2 are hard fixed with no damping to the frame to keep vibrations and resonates down. That is what part of the issues appears to be. Just done a quick measure of the PWM when fans is running slow the PWM is 50Hz at 8v DC and has quite a virbration to it, after fitting a crude capacitor filter across the motor connection it does make it less noisy but not by much, it sounds like the fan motor dose'nt like running at the lower speeds not realy designed for PWM applications signals, The fan like the Noctua is better suited to this application of PWM control.

I have one on order here in NZ to replace and report back on my findings

Regards

Rob D

NZ

1 Like 1 ·
popnic avatar image popnic Rob Duthie commented ·

@Rob Duthie I did an experiment on a testbench with Jamicon fan. I played with PWM frequency from 30 to 50Hz as you mentioned and different duty cycle at 24V . I got good results with a 10W 33Ohm series and 1000uF in parallel on the fan side.

I choose 33Ohm from 27, 33 and 47 ohm as a compromise for rpm of the fan and less noise.

27 ohm the PWM is noticeable. With 47 ohm the fan is running smooth but rpm is too low.

I do not want to open my Multiplus II because the option to send it back is still available.

Ron, can you experiment this for me in real conditions?

filter.jpg

Thank you.

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filter.jpg (15.2 KiB)
kevgermany avatar image kevgermany ♦♦ Rob Duthie commented ·

Nope, as coolers to shift some air over my batteries. I designed the compartment very badly and there's no convection.

The 50Hz explains the noise differences. I didn't try running the Noctua's at low frequency. Just decided to stay with their specs. Apparantly Intel said 30KHz to keep PWM noise inaudible. And that's the PC standard.

What I also noticed was that the smaller fans make fan noise earlier than the bigger ones - if my English makes sense.


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kevgermany avatar image kevgermany ♦♦ kevgermany ♦♦ commented ·
But I must add that it's important to use PWM at the PC standard of 30KHz.
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Rob Duthie avatar image Rob Duthie kevgermany ♦♦ commented ·
Hi Kev

Yes i don't think Victron are running at the higher frequency rate thats why they are noisy at low fans speeds this i have noticed on a few installs i have done with multiplus2 inverters to date. even the older modles the multigrid models as well.

So i have on order a Nocua fan to replace it in my unit to see what the difference it makes. as it has rubber damping mounts compared to the Jamicon brand which is hard mounted to chassis with no damping at all, so it will resonate in the enclosure which interns makes it sound very loud when running at lower speed so i will use my inverter personal as a dummy test unit, as i have a complete system setup with Vicrton gear etc to test these issues in real time applications in my workshop which is connected to the house.

Regards

Rob D

NZ

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n-dee avatar image n-dee Rob Duthie commented ·

Hi,

Which one did you order?

This one is looking really good:
Noctua nf-f12-industrialppc-24v-3000-q100-ip67-pwm

br,
Andy

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Rob Duthie avatar image Rob Duthie n-dee commented ·
Hi

Thats the one.

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kevgermany avatar image kevgermany ♦♦ Rob Duthie commented ·

Please let us know how you get on.

Some time ago I posed a question to @Johannes Boonstra (Victron Energy Staff) in his YouTube tech talks about fitting a quieter fan, his reply was the fairly predictable yes, but at your own risk and I've a feeling he also said it would invalidate the warranty. Obviously not a problem for you, but if anyone's reading and decides to try, be aware. I haven't taken it further yet. Might do. If the standard fan is low frequency PWM, I guess I could rig up an Arduino to convert that to 30KHz. But mine (compact in an easy solar) is quiet enough unless there's a big system load.

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Rob Duthie avatar image Rob Duthie kevgermany ♦♦ commented ·
Hi Kev

The Noctua fan won't realy start until the PWM is at higher output. I used a fan from a Dell server as well which are realy quite fans, the PWM comming out of Victron is crude to say the least, This made the DELL fan noisy as well, by the PWM pulses. On a normal varible regulated PSU super quite even the standard fan was very quite but soon as you add the Victron PWM noisy as.

I have added a 220uf cap across the motor output which has smoothed out the PWM and fan doesnt resonates no where as much. Also if i rubber mount the fan it will be even more quiter.

I do have a PWM generator i can change the Freq and Duty cycle which runs motors on to see were the sweet spot is. What we need is PWM output converter to voltage output filter.

Regards

Rob D

NZ

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kevgermany avatar image kevgermany ♦♦ Rob Duthie commented ·
Thanks Rob, good try, explains a lot.
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Pierre-Marie Baty avatar image Pierre-Marie Baty Rob Duthie commented ·
Very interesting. I'd be very curious to see what that "crude" PWM signal out of the Multiplus mainboard looks like on an oscilloscope, measured in time and frequency (FFT). Once we know what it really looks like, I bet something can be done to improve the problem !
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Rob Duthie avatar image Rob Duthie Pierre-Marie Baty commented ·
Hi

Around about 50Hz when running at slow speed or about 8v.

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Pierre-Marie Baty avatar image Pierre-Marie Baty Rob Duthie commented ·
I was more thinking in terms of signal cleanliness and harmonics but thank you nonetheless.
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Rob Duthie avatar image Rob Duthie Pierre-Marie Baty commented ·
The PWM is a clean signal, just the motor can't handle the low freq PWM signal, its to low so it makes the motor pulse and be noisy, needs to be set at a higher freq rate to smooth out the pulses. i am not sure if it controller by a micro or not if it is, a software firmware update will fix it?
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Pierre-Marie Baty avatar image Pierre-Marie Baty Rob Duthie commented ·

OK so if the signal is clean and the frequency is unsuitable for the motor, and considering the motor is wired with 2 wires (which means it should be able to be driven by a continuous signal), then the lowpass filter (popnic's method) is the best that we can do. That will effectively transform the PWM square signal into a quasi-continuous signal ranging from 0V (PWM = 0%) to Vcc (PWM = 100%)

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baxter avatar image
baxter answered ·

Hi,


up to know I thougth the fan is just voltage controlled, has it has only to wires (+ and ground).

Are there new multiplus II with a pwm controlled fan?


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Rob Duthie avatar image Rob Duthie commented ·
Hi

The multis have all being PWM controlled 2 wire fans, since day one, As i have owned a the older version and the newest versionof multis and all have the same noise issue at lower speeds etc.

Regards

Rob D

NZ

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baxter avatar image baxter Rob Duthie commented ·

For a PWM controlled fan 4 pins are required, at least for the Noctua Fans (and all fans I use in the PC settings).


So how to connect a 4pin Noctua PWM fan to a 2pin Multi? I guess there will be no PWM signal and the fan is only voltage controlled.


1651069850302.png

https://noctua.at/pub/media/wysiwyg/Noctua_PWM_specifications_white_paper.pdf


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Pierre-Marie Baty avatar image Pierre-Marie Baty baxter commented ·

Actually it seems they used an electronic trick, where the Jamicon fan is driven analogically with a PWM square signal that is lowpass-filtered by the fan hardware itself into a quasi-DC signal between 0 (when the PWM is at 0% duty cycle) and 24V (when the PWM is maxed out). The Multiplus fan is not really a PWM-driven fact in this regard, just an *analog* fan that's driven with a PWM circuit, instead of a DAC - probably because it's cheaper.


If you want to plug your Noctua, you'll need to use the blue, yellow and black wires. Tap a 24V DC somewhere from the mainboard to the yellow wire, match the black wire (ground) with the black wire, and send the red wire (PWM) through a dividor bridge that will lower the 24V PWM square signal from the Multiplus into a 5V PWM one compatible with your fan. That's how I'd do it.

*edit* sorry for my bad english ; by "dividor bridge" I meant this : https://en.wikipedia.org/wiki/Voltage_divider

1 Like 1 ·
baxter avatar image baxter Pierre-Marie Baty commented ·
Thanks for explaining this.

How weird is that

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Pierre-Marie Baty avatar image Pierre-Marie Baty baxter commented ·

Actually it's a rather common trick.

Choose your resistor values wisely: to bring down 24V PWM to ~5V, you need Z1 to be 4 times the value of Z2 (ex: Z1 = 4k ohm, Z2 = 1k ohm).

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Rob Duthie avatar image Rob Duthie Pierre-Marie Baty commented ·

Hi

That will work Ok just trying to avoid any soldering on the PCB and make it a plug in play type fix.

I am trying different T filter to see how to smooth out the pulses to the motor. So far not the best solution, just a 100 to 220uf cap makes the most difference but the fan runs faster of course.

I have used a PWM generator test rig to run a Noctua fan at the lower 1KHz PWM runs very smooth and is better at the 25kHz range better linear control down lower At the lower end of my PWM tester it won't go that low to test at the same as the Multiplus, need to change to re test at the 25Hz range same as the Multiplus.

Regards

Rob D

NZ

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kevgermany avatar image kevgermany ♦♦ baxter commented ·
The fourth wire is PWM in. Three wire fans omit this and simply feed the actual fan RPM back. Speed control is by voltage from the controller, often/usually in the form described by Rob - i.e. a PWM signal 'smoothed' to give a lower voltage overall. Hence they were called PWM, but.... The fan didn't read the PWM signal like the 4 wire fans do.
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baxter avatar image baxter kevgermany ♦♦ commented ·

Will the Noctua Fan work with just 2wires like the original one (only +24V and gnd) ? Based on the info I got from Noctua support the fan also supports voltage control without PWM Signal in.

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Rob Duthie avatar image Rob Duthie baxter commented ·
Hi Yes it does.
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iand avatar image
iand answered ·

I still don't understand why Victron do such a lousy job of fan speed control -- every single PC on the planet has proper HF PWM control to give quiet variable-speed fans and the circuits to do this cost next to nothing, so why on earth don't Victron do the same? And mount the fans on little silicone feet like Noctua do, the cost is pennies but it makes a big difference to noise from the case...

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kevgermany avatar image kevgermany ♦♦ commented ·
I'm not trying to justify anything but from a different perspective:

Current system works and is reliable and well proven

Many installations are in places where noise isn't a problem

More consistency in parts for maintenance

Other development priorities

Perhaps high frequency PWM wasn't as common when this was designed

Change is high risk-get it wrong and a huge number of units will give failures in the field.

All fans, even the super quiet ones, develop a lot of wind noise at higher speeds. The alternative is to fit much bigger fans at the cost of bigger units.


Having said that, I'd love the unit in my camper to have a much quieter fan. At all speeds.




1 Like 1 ·
iand avatar image iand kevgermany ♦♦ commented ·
HF PWM has been ubiquitous in all PCs for many years, the risk of any problems are probably lower than the existing solution, cost adder is close to zero.

The cost adder for bigger fans is negligible in the context of overall product cost -- if you want to be quieter and can fit them in they're quieter, but the product has to be designed for them -- which is too late for MP II and Quattro II.


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Pierre-Marie Baty avatar image
Pierre-Marie Baty answered ·

Well, it seems clear to me that vibration dampening and keeping sound levels acceptable were
*never* considered at all as possible issues by the designers of these products. It's to a point that many design choices that have been made were in fact the worst ones in this regard.

Now to recover from here... Apart from the forced air duct, or redesigning the enclosure completely and retrofitting the boards into a carefully hand-crafted one, I don't even think there's a proper solution.

I'm still watching this thread in the hope of a miraculous idea, but I'm slowly pushed into thinking it's a waste of time. Currently I live with it.

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popnic avatar image popnic commented ·
I contact Victron about fan noise issue. They come back to me thru distributors technical representatives in a day. They were fast and they listen me but we come to the conclusion that the unit is not faulty so the service is not necessary.


We are only a dozen of "sensitive" people here but remember:

Victron is powered by Multiplus II's and this is why they cannot hear us.

Personally I will not change anything in my Multi. It is a good product but is not for me. I lost the opportunity to send it back so I will keep it while I am looking for another inverter/charger.

Sorry to bothering you guys.

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Rob Duthie avatar image
Rob Duthie answered ·

Hi Bobby


I have modified a my own Mulitiplus2 unit with a Sunon fan 25mmx120mm model # EEC0252B1-0000-A99 with rubber mounts and with 47uf 63v cap across the fan terminals. And results are, the bad droning noise or PWM noise due the low PWM frequency you normaly heard has gone.

Much quieter unit now, no droning like before. just air flow noise though the unit now which is much more pleasant to listern to.

The air flow is the same as the orignal Jaicon fan, the 25mm thick fan allows for the rubber mounts to used on the original mounting bracket.

If Victron could just change the PWM to a higher frequency rate the problem would go away , and they would have a much quieter inverter on the market.

Regards
Rob D

NZ


fan-mod2.jpg

fan-mod3.jpg

fan-mod1.jpg


fan-mod1.jpg (2.5 MiB)
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Pierre-Marie Baty avatar image Pierre-Marie Baty commented ·
Excellent ! I'll try this model just like you did as soon as I have time to open that Multiplus-II again. And thank you for the pictures. Out of curiosity, what does the dB-meter say compared to the factory setup ?
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raymiller avatar image raymiller commented ·
Thanks Rob for getting to the bottom of the fan noise issue and providing some solutions, I have been wondering why my Multiplus 2 fan noise is like no other piece of equipment I've come across in my 40 years in electronics.

It would be good if Victron could bring out modification kits (hardware and software) to sort this out once and for all.

I'm not sure your noise isolation mounting is as effective as it could possibly be? Is the bolt and nut fully isolated?



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Rob Duthie avatar image Rob Duthie raymiller commented ·

Yes it is, the rubber damping is the isolation. it way better than the stock fan setup. It boils down to Victron to just change the PWM pulse to much higher frequecy rate and problem goes away, simple as that, i have tested with a higher rate and is much quiter on the standard fan. As there PWM pulse rate is only 25Hz too slow thats is why the fan drones.

Regards

Rob D

NZ


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kivanov avatar image kivanov Rob Duthie commented ·

Hi Rob, can this be fitted with the MP2 on the wall, or it has to be taken down on a bench?

Does it make sense to place 100-220uF cap instead of the 47uF (like suggested by mondeoman) in the in the context of fan effectiveness (when high speeds and air flow is needed, t.e. heavy loads), especially the possibility to pass the fan voltage limits?


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Rob Duthie avatar image Rob Duthie kivanov commented ·

Hi

Need to take down and remove the fan bracket to fit the fan etc. 100uF will be fine.. With the higher capacitance it make's the fan run slighty faster at the lower speeds that all.

Regards

Rob D

NZ

1 Like 1 ·
kivanov avatar image kivanov Rob Duthie commented ·

Hi Rob, thanks for your time with this and your answer.

Having look at the datasheets of both, the original one (Jamicon JF1238B2HR-R) is rated at 118CFM, while the Sunon EEC0252B1-000U-A99 is 108CFM.

The Sunon max current rating is also (0.238A) compared to the 0.31A of the Jamicon.

I suppose that your experiments did not show anything near the limits, so this can be safely be replaced?

p.s. Just to add the original fan connector to the MP2 board is H2P-SHF-AA. This should be a variation of JST 2.5mm pitch connector.

1 Like 1 ·
Rob Duthie avatar image Rob Duthie kivanov commented ·
Hi Kivanov

Yes that is correct, to date no issues, just a much quiter inverter system now.

I do this for all my clients to date due to the noise issue they complain about, as it runs slighty faster at the slower speed it cools down better, this is due to the capacitor interaction with the PWM pulse.

Regards
Rob D

NZ

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maa avatar image maa commented ·
Well done
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michaelvh avatar image michaelvh commented ·
Nice work @Rob Duthie , how did you find the noise improvement by using the Sunon fan and rubber mounts but without the capacitor in between, if you tested this? Was the droning noise just as bad as before?
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Rob Duthie avatar image Rob Duthie michaelvh commented ·
Hi

Only with a cap as this helps to smooth further the PWM pulse.

Regards

RobD

NZ

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raymiller avatar image raymiller commented ·

I added an extra supporting bracket (and a third rubber mount to the top of the fan) to stop the fan from sagging when the Multi was wall-mounted. This also allows for the mounting of the capacitor on the mount.victron-mulit-fan-mod-img-2909.jpg

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raymiller avatar image raymiller commented ·

I need to add an extra supporting bracket made from right angle aluminiumvictron-mulit-fan-mod-img-2909.jpg and a third rubber mount to secure the fan.

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gette avatar image gette commented ·

Thanks for your work on this.

I'm gathering components to do this.

Is 63v the ideal voltage?

Seems 63v isn't as popular as 50v or 100v.


What about the 47uf, vs 100uf vs 220uf I've read about?

Whats the advantage/disadvantage of using the 100uf or even 220 vs the 47uf (if the 100 or 220 is quieter?)?


Thank you all for the help!

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Rob Duthie avatar image Rob Duthie gette commented ·
Hi

Higher the better is OK the more mfds its smooths out the pwm more.

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gette avatar image gette Rob Duthie commented ·
Thank you sir!
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Rob Duthie avatar image
Rob Duthie answered ·

Hi

Didnt not have a dB meter, just it is much quieter than before no droning noise.

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mondeoman avatar image
mondeoman answered ·

I can also confirm that the recommended SUNON EEC0252B1-A99 (EEC0252B1-000U-A99) fan is much more quieter than the original fans of the Multiplus-II.
The fan is available on the SOSElectronic website in EU and is cheap.

I used a 220 uF capacitor because at 47 and 100 uF I could stil hear some "vibrations" from the PWM at low speeds.

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uzi10 avatar image uzi10 commented ·
is this fan good an quite at low pwm speed?
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Rob Duthie avatar image Rob Duthie uzi10 commented ·
Yes
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ecoman avatar image
ecoman answered ·

Hi folks, first time posting here. I also belong to the surprised, noisy Multiplus II owners club, mine is the biggest 10kW version. I almost fell off my chair when I heard the fans starting the first time. That was under a light load of about tad over 2kW which one would think to be easy for a 10kW unit (well, maybe 8kW instead of 10kW name tag) but anyway, only a fraction of max. The unit is brand new, and naturally Victron will not consider faulty, so no warranty claims to be done. As such, I am considering the same modification as you have done - but one thing caught my eye in the SUNON EEC0252B1-A99 (EEC0252B1-000U-A99) fan mentioned in this thread. The fan spec says the following, and I would like to hear how do you read and understand it.

On page 11 of the spec, they tell not to use PWM control with it:


1653322061248.png


Ie, the way I read it is that the fan has only two pins, power and ground, and neither of those should be used with PWM signal. Wonder if it means the fan will die prematurely without warning, or smth else? Should we find another fan which is ok for PWM control?

Thoughts?


1653322061248.png (25.3 KiB)
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Pierre-Marie Baty avatar image Pierre-Marie Baty commented ·

Yep, that's why the modders use a capacitor+resistor setup to create what's called a "lowpass filter" that effectively transforms the square wave PWM signal into a continuous DC signal that's harmless for that type of fan. If you do exactly what Rob Duthie did, it'll be okay.

I don't think you should take the datasheet advice literally (that the fan speed can't be adjusted). That fan is just a DC brushless motor, and I fail to see how driving it with a variable DC voltage to control its speed would harm it as long as its nominal voltage isn't exceeded. I might be mistaken here though (for example, that fan would be a stepper motor, which would require some complicated electronics driver card, but I'm yet to see a fan like that).

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Rob Duthie avatar image Rob Duthie commented ·
Hi

Well the Jamicon fan is a very similar fan design so will have the same issue as it has a bushless design as well, The noise it makes suggest that can't be good for it either. At least the Sunon has better data sheets than the jamicon fan.

Well to date the sunon works a treat and is way quiter.

All Victron has to is change the PWM rate and all will be well.?

Regards

Rob D

NZ

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ecoman avatar image ecoman Rob Duthie commented ·
Thanks for quick responses folks, I share your views on filtered DC being certainly being more gentle on the fan than Victron design bare PWM square wave at 25Hz making the fan cry out loud. Adding a capacitor will result in higher average voltage and thus higher fan speed (just more cooling than designed :o) ). Reading your text (Rob), you mention only the capacitor across terminals, no resistor. Is that how you ended up setting it, or did you actually add the resistor also (not shown in pics). A resistor could be used to keep the fan speed the same as without RC circuit, yet top revs would be lower compared to original setup when PWM at 100% - so I guess your setup is just fine. I'm just curious on whether you used a resistor or not, and how do you see pros and cons of it?


Thanks.

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Rob Duthie avatar image Rob Duthie ecoman commented ·
Hi

Not used a resistor as it did not make much of a difference, but only used a 47uF value cap only a made a slight increase in speed, but very much quiter overall. compared to before. The rubber mounting improved it much better again.

Regards

Rob D

NZ

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sharpener avatar image
sharpener answered ·

Perhaps it would be good to add a series resistor anyway as @popnic suggests, so that the source of the PWM waveform (whatever it is) doesn't drive directly into a capacitive load. Depending on the source impedance, that could result in very high peak currents which would not be good for either the driving circuitry or indeed the capacitor. Like @RayMiller I too was surprised by the very "agricultural" fan noise from my new MP II, for its size it is certainly the noisiest fan I have encountered in a long career in electronics.

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ecoman avatar image
ecoman answered ·

Hi Rob, all, and thanks for sharing your implementation, I'll be doing the same mods once back at my remote facility. I will also take my oscilloscope with me to see the signal waveforms and mean voltages before and after changes and can post my findings here.

BTW, does anyone know if the noise originates from just one fan or both in the Multiplus II 10kW model? (would expect Victron to run both fans with the same low freq pwm, though...). Do the smaller models have two fans like the 10kW one, or just one?

Looking at the fan specs, it shows 24V, 207mA, which works out to be the 5W. Thinking of the serial resistor and the impact of it on the power the fan receives, I did a rough math below. This is lacking the effect of the capacitor boosting the speed, and the current value is an estimation, so not exactly accurate but should provide some clues on how the serial resistor size impacts on fan output.

Voltage resistor resistor pwr max fan voltage fan current fan power % of nominal
24,0 V 0 ohm 0,0 W 24,0 V 0,207 A 5,0 W 100 %
24,0 V 5 ohm 0,2 W 23,0 V 0,198 A 4,6 W 92 %
24,0 V 10 ohm 0,4 W 22,1 V 0,191 A 4,2 W 85 %
24,0 V 15 ohm 0,5 W 21,3 V 0,183 A 3,9 W 78 %
24,0 V 20 ohm 0,6 W 20,5 V 0,177 A 3,6 W 73 %
24,0 V 25 ohm 0,7 W 19,7 V 0,170 A 3,4 W 68 %
24,0 V 30 ohm 0,8 W 19,1 V 0,164 A 3,1 W 63 %
24,0 V 35 ohm 0,9 W 18,4 V 0,159 A 2,9 W 59 %

Ie, it would seem that already a 33 ohm resistor would cause the fan to receive only ~18V instead of 24V, and reduced current, resulting in about 60% of the fan power compared to what the factory setup with 100% duty cycle 24V feed would provide. While the fan spec doesn't tell how much less airflow that would mean, I'd guess it is going to be significantly less, probably in direct correlation with fan power and that would discourage using resistor values that high.

As such, it would seem that the implementation by Rob with no resistor is the safe one from maintaining the same (in fact, better) airflow, although a small resistor (say up to 10 ohms) should not cause too dramatic power drop, especially considering the boost from the capacitor which might compensate enough to keep the fan power and thus airflow close to factory spec.

Also, if using only 10 ohms resistor, a 1W model would be fine, as the power dissipation on the resistor would never exceed 0.4W. The 1W rating would actually be ok all the way to 30+ ohms. Then, is there a value of using such a small resistor even to protect the driver circuitry from the change in load impedance...?

Thoughts?

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Rob Duthie avatar image Rob Duthie commented ·
Hi

The resistor will get hot and over time this will fail as i have seen in the past with other fan circuits. The capacitor by itself is simple and effective and no heat is generated.

I will be fitting another fan to a clients Multiplus2 unit which i am installing in case they complain about the noise, i will check the impeadance of the output fan ciruit to see what i can measure etc.

Regards

Rob D

NZ

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ecoman avatar image
ecoman answered ·

The new SUNON EEC0252B1-000U-A99 fans arrived, but no rubber mounts included, so need to find or create ones. Tested at home without PWM, just straight 24V corresponding to 100% pwm signal, with and without 10 ohm/3W serial resistor.

Without serial resistor and free airflow I get 24V and 192mA = 4.61W power consumption (100%). With airflow obstructed (fan against the table), current increases to 215mA and power to 5.2W

1654199027525.png

With serial resistor current drops to 170mA, power draw to 4.08W (89%); voltage over the fan to 22.1V, thus 3.76W for fan (82%), and 0.32W (7%) for resistor, which warms a bit but hardly noticeable with finger. With multimeter temperature probe I get a reading of 40C, correlating with finger reading. Based on above numbers, the actual resistor value is 11.2 ohms.

With obstructed airflow current increases to 190mA, power draw to 4.56W (99%) of which fan gets 4.16W (90%) and resistor 0.40W (9%). Resistor temp now 43C. The resistor was in standstill air, not in fan airflow. In MP2 the resistor would inevitably get some airflow, yet it is a warmer environment than +23C now. Tested also with the second fan, got the same readings - so these fans seem to be identical twins. (I ordered two fans as MP2 has two and I don't know if it is one or the other or both making noise - assuming worst case).

Based on quick testing I figure I could use a small serial resistor, lifetime should not be an issue due to minimal temperature rise. Will see if the resistor makes any difference in results, will decide once I get to try the alternatives. Surely without a serial resistor the circuit is most reliable as only one component to fail and no chance of cutting the circuit like failed resistor can cause; yet both have the same chance for shorted capacitor which can also happen.


1654199027525.png (27.2 KiB)
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Rob Duthie avatar image Rob Duthie commented ·
I used these rubber mounts from RS Comp # 126-3939 they come in a pack of 8

and put a pice of foam on the bracket as per my thread photos.

Regards

Rob D

NZ

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ecoman avatar image ecoman Rob Duthie commented ·

Thanks, the same seem to be available here also, will get those rather than re-inventing the wheel.

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ecoman avatar image
ecoman answered ·

An update, things seem different with the 10kW model of MP2 - and so far I have not succeeded in making the device quieter. First, the fans are different, and there are two of them. Second, the capacitor makes no difference on the noise the MP2 generates, I tried 47, 100, 220 and 330uF capacitors parallel to both fans with only marginal impact on noise.

Ths lower power fan is JF1238B2HR-R, 24V 0.32A = 7.7W fan, and the higher powered one is JF1238B2TR-R, 24V 0.60A = 14.4W fan, both JAMICON as in other models. However, the 5W fans I bought based on the information from smaller systems would not most likely not be adequate replacements, and would not be able to generate the same airflow and cooling.

On the signal waveforms, I didn't capture them at all power levels, but here some samples when the inverter was under a modest, bit over 2kW load. The first one is without any capacitors connected, standard Victron factory setup and showing just one of the fans voltage. To be noted that both fans were driven with exactly same kind of voltage and frequency PWM signal

1655978988324.png

The second oscilloscope screenshot shows the voltage of both, each with 47uF capacitor connected...

1655979428983.png

...and the last one with 330uF capacitor on fan power feed:

1655979562184.png

As you would expect with the largest capacitor, the peaks smoothen and the lowest voltage is no longer zero but a slope towards zero volts, until the next peak comes in. BTW, the scales in the oscilloscope were 5V vertical (in single graph displays, 10V in two channel displays) and 20ms horizontal division. As you can see, we get about 5 full phases in 8 intervals on the screen - ie. 8x20ms = 160ms for 5 pulses, which makes about 32 ms pulse interval, or about 31Hz frequency. I don't know yet if the PWM frequency changes along with the load, but at least in this case it seems to be slightly different than the 25Hz mentioned earlier, but maybe the same control circuitry with "approximately" 25Hz...

Just for the sake of it, here few more samples of the same signal with slightly different load - as you can see, there are varying number of peaks on top of the pulse, not clear if intended or just a by-product of the fan control circuit. Whatever the case, those seem to be 4 peaks in approx 13..14ms, or ~3.5ms per phase, or about 300Hz frequency. That's another nasty frequency to listen.

1655980262161.png

1655980212229.png

The next thing I'll try is to disconnect the Victron fan control completely, and drive the fans with plain DC power from a lab power supply to see if a plain DC voltage on the fan (mounted in the frame as is) would generate noise, and if so, which level. That should establish the reference which can be achieved with Victron standard fans. If still noisy, should see if a quieter fans could be found. If clearly less noise, then I'm thinking that it should be possible to convert this PWM to plain DC (0-100%) analog voltage. There are converters which change PWM to 0-100% voltage level, but the ones I've seen so far are all either 0-5V or 0-10V output, have not found any with 0-24V output. Yet it should be possible to convert to that range with a simple circuit.

Thoughts from your experiments and findings, and what do you think about changing PWM to just DC level 0-100%?


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Rob Duthie avatar image Rob Duthie commented ·

By just putting in the rubber mounts and changing out to the fan to a Sunon fan the reasonants goes away much quiter inverter allround i have being running this for about 4 months now with no issues and piece of mind. And just a 47uF 63v cap across the motor wires. just try this nothing to loose, dont get to hung up on the PWM issues this won't go away until Victron acknowledge the have a poor PWM control for there fan cooling very simple.

Sunon EEC0252B1-0000-A99

I used these rubber mounts from RS Comp # 126-3939 they come in a pack of 8

and put a piece of foam on the bracket as per my thread photos.

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ecoman avatar image ecoman Rob Duthie commented ·
Yes, I've got the same rubber mounts in my hands right now, the problem is that for the MP2 10kW model they cannot be changed without unmounting the whole unit and undoing the screws in the backside of the unit. Given the weight of 50kg and tight space, it is no easy feat to get it off the wall, but doable if must. The other problem is that the new 5W fans I have are only 1/3rd of the power of the original and cannot push as much air against the counter pressure, so even if changing the fans I need to find ones which can keep up the same airflow in the same chassis. I now have a DC power supply on site, so I can check if plain DC feed will run the fans quietly.
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raymiller avatar image raymiller Rob Duthie commented ·
Thanks for all your work Rob, I was slow to move, looks like the fans are in hot demand and not in stock in most places I have access to in Australia, RS supply is August and Mouser 2023.


I also note the Sunon fan bearing is magnetic offering lower vibration transmission, ideal for Victron Inverters.

All we need now is to be able to change the fan by just removing the top cover, as opposed to disconnecting the inverter and lowing 10's kg all the wall.


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Rob Duthie avatar image Rob Duthie raymiller commented ·
Hi Ray

The fans are avaible In NZ from my supplier they are in stock. HiQ Electronics.

I have done a couple now for my clients to keep them happy.

Yes i prepare them before installing them, yes you have to remove the mount to mount the new fans on to,only done the 5Kw models to date.

You could do from the top just need a right angle screw driver to remove the old fan.

Does the 10 kW model use the same Jaimcon fan?

Regards

Rob D

NZ

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ecoman avatar image ecoman Rob Duthie commented ·

While the fans in the 10kW MP2 are also Jamicon, unfortunately they are not the same 5W fans as in smaller MP2 models. The fans in the 10kW model are much more power hungry, 7.2W and 14.4W according to the specs posted earlier (although the math gives 24x0.32A=7.7W instead of spec'd 7.2W). Below the model numbers

JF1238B2HR-R, 24V 0.32A = 7.7W fan

JF1238B2TR-R, 24V 0.60A = 14.4W fan

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ecoman avatar image
ecoman answered ·

Googling for the specs of those fans, this is what I found:

1655983906984.png

1655983729318.png

Which says the bigger fan alone produces almost 53dB at full speed, while the other is about 10dB quieter.


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iand avatar image iand commented ·

Wow, a 4000rpm fan is going to make a *lot* of noise in the MP II 48/10000 -- and presumably the Quattro II 48/10000 when it emerges. Which is a pity, because that's what I was intending to use... :-(

Does anyone know what the fans in the original Quattro 48/10000 are -- are they quieter?

Ecoman, how did you find out which fans the MP II 10kVa uses?


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ecoman avatar image ecoman iand commented ·

Simply by opening the box and looking :o). Ie, I bought the MP2 10kW model without any clue about the loud noise it makes, only to discover it once installed. My previous inverter (Studer HPC 4.4kW) was silent, and it never crossed my mind an inverter with 2x the output would make such loud noise.

Here the pictures from inside the MP2 10kW model, you can see the lower rated fan on the bottom left side, and the more powerful one further up on the right side of the unit. On the top there is a massive toroid transformer which makes up most of the unit weight (49kg).

img-20220611-185118.jpg


Photos of the fans below. Those cannot be replaced without taking the unit off the wall, as it seems the mounting brackets are screwed through the back panel. Will update if I find another way to do it or find a way to otherwise dampen the sound a bit. For now, I have only the 5W fans I thought could be used, but apparently not.

Top fan:img-20220611-165211.jpg


Bottom fan:

img-20220611-165221.jpg
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iand avatar image iand ecoman commented ·

Looks like the high-speed (4000rpm 0.6A) fan is cooling the heatsink (by pulling air through it) for the power MOSFETs which is behind the PCB in the bottom right corner, which is where most of the heat dissipation will be. What's annoying is that Victron could easily have used a slower-speed 140mm x 25mm fan (like the Noctua industrial one) which would have been a lot quieter and given more airflow... :-(

The low-speed (2800rpm 0.3A) fan is just generally blowing cool air up through the case and across the transformer.

I don't suppose anyone with an original Multiplus/Quattro 48/10000 has done the same thing and looked inside? ;-)

1 Like 1 ·
maa avatar image maa commented ·

Hello ECOMAN,

and now where are you with your improvements?

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ecoman avatar image ecoman maa commented ·

Sorry for long silence, have not been here since last post, given the apparent dead-end I ran into. What I did after the initial tests documented above, I used a lab DC power supply to feed both fans at 24V, which showed 0.79 amps current drawn, approx 19W instead of spec'd power of 14,4W+7,2W=21.6W, but close enough to hear the result. To my disappointment, the noise remained at very high level anyway - which is expected given the fan spec says 52.9dB for the bigger one. Thus I concluded that there's no way to silence the fans even if driving at higher frequency, as flat DC couldn't do it.

It also seems that there are no 120mm fans which could maintain the same airflow and static pressure without much less noise. The best Noctua 2000rpm fan gets to 44% airflow with 29.7dB, and the 3000rpm fan to 67% @43.5dB.

A bigger 140mm fan would be quieter for the same airflow, Noctua has one which is 97.2% of the original fan airflow at 41.3dB - that is almost 12dB less - but I doubt it would be possible to make it fit without major modifications inside the box, like moving the pcb on the right side couple of centimeters further up... and even if done so, would the increased area for airflow be constrained by the cages/components below it, could well be - but cannot check it anytime soon.

Note that I am with 10kW MP2, not the 5kW unit - so it must have even higher cooling requirement and the thing weighs 50kg, not so easy to get off the wall for mods. Reading about using less than half airflow fans because the unit is at <25C temperature, and to hear about dealer changing those for their customers seems risky at best but certainly an option when the ambient temp remains low enough.

Granted, my unit does not run at full power for extended periods, but it does run at over half power for long periods - for example when charging two hybrid cars at low power (2..3kW each), or one car with built-in 7.4kW charger while the rest of the house consumes as usual. At those times I want to be sure MP2 doesn't get damaged with overtemp. I don't have information on how good the output derating is, and whether it would be enough to save the inverter when under, say hours of 6..8kW load with ambient temperature slightly over 30C.

Ie, so far I am without a solution to silence the beast, but would definitely like to find one, even if it would require a serious mod to the inverter.

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teckau avatar image teckau ecoman commented ·
Hi Ecoman,


I just registered to write a message to you only to find out that this forum seems not to provide direct messaging. Ok then, here we go (even if I am afraid you might not be here too often):


First of all (and this goes to everybody reading it): Happy new year all the best in 2023!!!

I have an installation in Sevilla based on a 48/10000/140. First time solar things in my life, I am an IT guy with electronics skills, but no: This is all shiny and new to me. 2-3 months ago I had powered up my newly installed system and fell off the chair like you with that noise level. I have no EV now (but planning for) but in Seville we have some 45-48C in summer. Guess how many ACs are running then... But, yes, at THOSE moments there is for sure enough noise from the ACs, though.


But back to serious talking: I bought 2 Noctua fans just to find you testing and now I am frustrated. Cancelled my orders on caps and diodes and all that stuff and now I am looking for a solution. You need one, I need one and it seems we are few (10000er). So I registered to offer help in exchange for help. Maybe we can work on that together? You can write me an e-mail if you want or you can just keep the communiation here. In the first case use my first name (Thorsten) and my last name (Eckau) to form the address like in first@last.de


I would like working on this with you if you also would like to. At least we could exchange all information on what's NOT working so far (which might happen in this forum for others to read it). Currently I am thinking that an external solution with a 220V fan blowing INTO the inverter might be a solution, what do you think (as a person having opened it already and beeing familiar with the internals)?


Best regards

Thorsten


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johnone avatar image johnone teckau commented ·

Hi, not sure if this helps you but devices manufactured from mid-summer 2022 have a modification (to the electronics controlling the fan) which gets rid of the annoying noise. I have a serial number HQ2226 (manufactured 2022, week 26) 48/5000 which is nice and quiet - no appreciable fan noise. See here for serial numbers of devices with the modification.
https://community.victronenergy.com/questions/164077/too-many-buzzing-noise-complains-coming-from-multi.html

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teckau avatar image teckau johnone commented ·
THANK YOU, this is really an interesting information for me! My device - even if it had been installed just recently - ist HQ2146. So quite old. This leaves room for me to think about replaceing it 1:1 with a newer and selling the old unit to someone that is not sensitive. I have no place to mount the Victron but in the entrace of my little house so the noise is well distributed to all of the rooms :/

Any idea how I could find out how this improvement "sounds"? I will have to do the math (because the swap will cost me money) if that's worth or if I would go an open my box and do dirty things like disconnecting both fans and installing an external cooling of some sort...

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johnone avatar image johnone teckau commented ·

A video from just now - 48/5000 mounted on a memory foam mat.

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ecoman avatar image ecoman teckau commented ·

Hi teckau,

Indeed, you were 100% right, I don’t visit the pages often, I need to improve on that. Had I known about your post, I would have jumped on it right away. I guess there is no mechanism to subscribe for notifications on given topic, or is there?

So, you also have a 10kW unit with super-loud noise, unless you have done smth about it already? I saw the interesting post in response to yours from johnone, talking about the modification on the 5kW model since mid-summer 2022. I would be very much interested in finding out whether similar modification has been done with the 10kW model – the 5kW unit mod doesn’t help those of us with 10kW model as the fans are more powerful, requiring different electronics (at least higher currents) to drive those.

I sent an email also to the address provided (assuming I understood the format correctly), let's see if we can get in touch one way or another. Naturally will share any improvements here also.

Given Victron has done something to decrease the fan noise on the 10kW model also, I would be very interested in finding out what, and how much is the impact. If Victron doesn't respond with such information, I am sure we can measure the difference ourselves, just need to ensure we use the same tools and environmental conditions for the measurement.


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andreas-siebenmorgen avatar image andreas-siebenmorgen ecoman commented ·
Scroll down to the bottom of this page and find the answer :-)
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maa avatar image
maa answered ·

Hello dear Victroniens and Victronniennes,

Concerning the subject of fan noise, I suggest you make an online petition on this forum in order to accumulate the greatest number of VICTRON customers.

So we could ask VICTRON R&D to include at least in the future version of the Multi-II Firmware the fact that the fans are only triggered according to the internal temperature of the device and more on a mix.

If you agree, here is the link to this petition:

https://community.victronenergy.com/questions/157987/petition-bruit-ventilo-multi-ii-noise-fan-on-multi.html

Victronement your

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mondeoman avatar image mondeoman commented ·

@Maa I periodically read the Firmware Changelog published on the Victron Professional website.

Firmware xxxx496, released April 19, 2022, contains a clear indication that the fan is also started proactively based on actual current, not just temperature:

Minor improvement on fan driver.

(Under certain specific conditions the fan did not start even if the average current indicated that it should. This is a minor improvement since it did not impose a real problem because the fan could still start based on internal temperature sensor.)


Personally, I think this is good, but the only problem is that the MultiPlus II factory-default fans are noisy.

1 Like 1 ·
maa avatar image maa mondeoman commented ·
Thanks Mondeoman for this information. I pushed it on the French Forum.
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sharpener avatar image
sharpener answered ·

It seems this is a serious problem for many domestic users (myself included, I have had to soundproof the door of my kitchen because of it). So it is regrettable that Thierry Cortassa (Victron Energy Staff) has closed the Petition topic rather than taking the request for action seriously.

As noted above by many contributors to the discussion, there are various technical solutions which could easily be adopted to solve or at least improve the noise problem if Victron had a mind to do it.

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rvicev avatar image
rvicev answered ·

Thanks to all the efforts by contributors above and in other threads on the Victron Community platform and elsewhere, we now know that the fans start based on :

a) ambient temperature of ca 30-35C

b) power drawn (actual current)

However, there seems to be one aspect missing in above discussions.

According to Victron specs the MultiPlus will work in ambient temperatures of -40C to +65C, with derating at higher temperatures, of course. Very impressive !

I´d say that at 65C in a residential environment you won´t be bothered by the noise of the MP II, because you have very serious other problems. Still, it is very impressive because at 65C the air blown through the MPII has very little cooling capacity. That means a lot of air has to be blown through the MPII, requiring a very powerful fan.

Common sense therefore says that if you are sure that the temperature where you will be installing the MPII will never be higher than e.g. 25C, you do not need such a powerful fan .....

No surprise therefore when I came across this link https://www.photovoltaikforum.com/thread/158718-lautst%C3%A4rke-multiplus-ii-48-5000-70-l%C3%BCfter-brummen/?pageNo=1 (in German) where German reseller Panda-Solar states that they have been installing the 2000 rpm version of the Noctua fan for clients, who have them running without any problems for more than 2 years. Difference being that the 2000 rpm Noctua has a noise level of 29.7 dB, whereas the 3000 rpm produces 43.5 dB .........

The difference between a whisper and an older model dish washer.

I love the sound of silence.-

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sharpener avatar image sharpener commented ·
But the objectionable nature of the noise arises from the way it is driven, by a relatively low-frequency PWM variable-speed signal with no smoothing.

A fixed speed fan would be much less annoying, even it the measured noise level was the same.

So if you are going to modify the inverter and so invalidate the warranty then IMHO it would be better to fix this aspect of the problem first. Unlike Panda-Solar's approach, the mods described by @Rob Duthie and others do this with at most a trivial reduction in maximum flow rate so the noise is reduced but the thermal management of the inverter is virtually unimpaired.


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Rob Duthie avatar image Rob Duthie sharpener commented ·
Hi Sharpener

Good call, is Victron is listning? NO?

Regards

RobD

NZ

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rvicev avatar image rvicev sharpener commented ·

I fully agree that you should get rid of the noise caused by the low freq PWM variable speed drive in combination with the fan provided as standard, i.e. better quality fan, mounted with little rubber silent blocs and capacitor.

I merely suggested that you can go even further under specific conditions. Note that I did mention : a) residential, b) temperature never above 25C. I can´t see how you would impair the thermal management by getting rid of excess fan capacity you simply don´t need. The dB scale being logarithmic, there is a huge difference between 29.7 dB and 43.5 dB

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Rob Duthie avatar image Rob Duthie rvicev commented ·
Hi

Yes i added rubber mounting isolators as per mod notes.


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sharpener avatar image sharpener rvicev commented ·

The software will not know it is a smaller fan. So at all fan settings there is a risk that the fan will only deliver 2/3 of the air flow the s/w is expecting. Even if there is closed-loop control and additional protection e.g. backstop overtemp sensors this will give higher internal temps and hence reduced life/reliability, even in a domestic setting. (My first big project involving heat sink design was over 40 years ago and I am still learning.)

Under some circumstances the 5kVA unit installed in a cool room on the N side of my house still emits exhaust air at I am guessing 50C so I would not want to do this.

My wife's solution is to isolate the inside of the glass panelled door to the kitchen by putting old towels in contact with the glass to stop it vibrating in sympathy and to absorb incident sound. This has the merit of not requiring me to disconnect the 30kg Multi and take it off the wall to get at the fan mounts which AIUI are on the rear of the unit.

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rvicev avatar image rvicev sharpener commented ·

Software doesn´t know anything about fan capacity at all, whether it be bigger or smaller.

All the software sees is a temperature, if I understood correctly from this and other forums the measurement is done via a LM35 (accuracy in theory +/- 2C, in practice at best +/- 3C, so fairly inaccurate). If temperature passes a low threshold the software will start the fan at a certain low speed and if temperature continues to increase, it will simply ramp up the fan speed.

The only thing that matters is if, once it arrives at 100% fan speed, that is still sufficient in case you put in a lower capacity fan. Normally that would be guesswork, and I had say : no, don´t do it.

However, under the specific conditions I stipulated – residential & T always less than 25C – the experience of German reseller Panda-Solar has sufficiently proven to me that the lower speed Noctua industrial fan (or similar) is sufficient.

Yes, you have to take the Multi of the wall to make any of the suggested mods in this thread and yes, unfortunately that thing weighs 30 kgs (but mind you, It can be a lot worse e.g. a comparable Outback Radian weighs ´only´ 40 – 60 kg, so be happy that you choose Victron .... )

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mathieu-van-den-berghe avatar image
mathieu-van-den-berghe answered ·

to add upon the others.


MPII 48/5000


when not charging/inverting : loud humming noise

when above 2kw : fan kicks in and noise is annoying : goes through all the walls, neighbour complaints, discussion with wife, sleepless nights etc

modified the MPII with resistor/capacitor as stated above. Makes it a lot better, but still ...

to comment on the airflow : by adding the resistor, the maximum airflow is less. I use the inverter for hours at max power. I see that with ambient temperature of 20 degrees, it gradually decreaes its output power to around 4400W instead of 5000W, this happens after 10 minutes or so. probably because it's running to hot. so for many situations, adding a more silent fan, that switches 100% on from the moment a PWM signal is seen, should be good, unless you need the full 5000 W for prolonged periods.

personally cannot believe that someone can have this unit in a boat/RV.



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1234enough avatar image 1234enough commented ·
I have multiplus ii gx 48v 5000va and agree it is noisey, haven't tried any modification as yet, what did surprise me when I took the cover off was how poorly air sealed the fan was to the case /from one side to the other side of the fan with gaps around the fan case, this must cause quite a bit of re-circulation of air, in turn causing the fan to be less efficient than it could be.
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Charlie avatar image
Charlie answered ·

to the experts here, anyone knows is the noise situation is the same with the Quattro's? will I have twice the noise in parallel configuration? thx u

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johnone avatar image johnone commented ·

Not an expert, but can point you to a serial number issue you might like to be aware of. According to the Victron man, you need a Quattro with a serial number of HQ2230 or later, if you want the much quieter ones. 2230 being 2022, week 30 (25th July). Lots of suppliers will have units made before that date - up to you to make sure you get the updated version with the quieter fans. See here:

https://community.victronenergy.com/questions/164077/too-many-buzzing-noise-complains-coming-from-multi.html

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raymiller avatar image
raymiller answered ·

Bobby the fan noise as you state is excessive, the fundamental problem seems to be the fan model being used. The centre cover ( which is large for a fan) of the fan electronics resonates easily which is causing an unusually extra sound emanating from the fan bearings, made worse by any PWM speed control.

I've successfully replaced my fan (as per Rob in NZ) with one, half the thickness and used fan mount isolation rubber mounts as suggested. The PWM of the replacement fan does not seem to make any extra noise.

I did at the same time add a dense stick-on noise-reducing material to the inside of the front panel which also helped reduce the MulitPlus case resonances. The final result is white noise from the inverter when under load, no more noise than what one would expect from normal fans and similar to Fronius inverters, and much less annoying.

Unfortunately to replace the fan requires removing the inverter fully to access the rear screws holding the fan mount bracket, although Rob seems to think it can be accessed from the rear on-site, I found it still much easier to have the unit on the workbench.

It's a simple mod but one which would not be necessary if a different model fan was used.

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nickdb avatar image nickdb ♦♦ commented ·
It has already been stated on other topics, but most of the models made from middle, or so, of this year have a different fan setup and they are nice and quiet (ish). It is a huge improvement.

I have put them side by side for comparison.

It is pretty close to the mod mentioned on this thread.

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michaelvh avatar image michaelvh nickdb ♦♦ commented ·
That is great news @nickdb. Out of curiousity, did you by any chance have a look inside already to see how it differs from previous models? Different fan model or mounts, or just different fan control?
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nickdb avatar image nickdb ♦♦ michaelvh commented ·
Not yet, but I do intend to.
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grobalt avatar image grobalt nickdb ♦♦ commented ·
That would be great :)
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grobalt avatar image grobalt commented ·
There is no replacement fan that delivers the same CFM than original with less noise. Maybe just the PWM is handled different with the other fan.
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pmikep avatar image
pmikep answered ·

I found this thread because, for the first time in two years, the fan in my Multiplus (original) 24/3000/70 came on today. (A few days ago I upgraded my battery bank to 3p2s 24V/100 Ahr, increased the charging current to 21 Amps and increased the AC input limit to 8 A (120 VAC). Due to rain all day, the charging circuit turned on today, and the fan turned on shortly after.)

Even tho this thread is about fan noise in the MP II, the fan noise in my MP got my attention. I thought the fan blades must have been in contact with some wiring because that's what it sounded like with the rattling/vibration. But when the fan is off, the blades turn freely. So there's no mechanical interference.

The reason that I post here is because I noticed something else that I haven't seen stated in this thread. The fan assembly seems somewhat inefficient, in that I can feel air blowing backward at the fan intake!

As someone who build an airplane (a real one), I know that air doesn't often flow as we expect it to. Looks like I will have to take a Dremel tool to the shroud and smooth things out. Or add some baffles.

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Ondra avatar image
Ondra answered ·

Ahoj,

Velmi užitečné vlákno. díky

můj velký problém s hlukem jsem vyřešil takto :-)

https://forum.mypower.cz/viewtopic.php?f=7&t=8299#p167566

Bitumelová výplň.. Nyní jde slyšet jen fučení vzduchu z ventilátoru.

Slunci zdar

Hey,

Very useful thread. thanks.

I solved my big noise problem like this :-)

https://forum.mypower.cz/viewtopic.php?f=7&t=8299#p167566

Bitumel filling... Now you can only hear the air blowing from the fan.

Sunshine.

............

Translated with DeepL


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ecoman avatar image
ecoman answered ·

Hi all noisy MP II owners, here the latest from my side. As Victron came up with the fix (PWM frequency change PCB) for the 5kW models in February, it didn't apply to the 10kW model, so I asked Vicrton about the 10kW models, and in May they came out with an updated doc which now also covers the 10kW MP II, and includes two PCBs to install, one for each fan driver circuit (SPR00090 and SPR00091). Reached out to my dealer asking about the 10kW kit, and got it in about 2 weeks - and as soon as I was back on site (early July), I installed the mods.

Before doing so, I measured the noise with multiple different phone dB meter apps, using couple of load levels (2.5kW and 4.6kW). Didn't bother trying with higher power levels as according to Victron the max cooling noise doesn't change with the mod.

After the mods had been installed, I repeated the same measurements using the same load levels and measuring from the same spot/distance from the unit. I am not posting the dB readings here as I don't think any of the apps I used provided accurate results - however, despite of the actual value maybe being way off the real number, at least the same app should tell the difference in noise level before and after.

To my disappointment, there was very little difference in dB's the sound measurement apps indicated, hard to say if even 1dB overall - however, the kind of noise it makes changed to far more pleasant, just fans humming as others reported, the nasty droning sound is gone!

I then looked at one of the apps which has a spectrum analyzer also, and while these are not exact numbers (pulled estimates from graphs), there is a clear difference downwards, up to 10dB at some frequencies. Here's the difference calculated from two spectrum analyzer graphs (I should have done multiple measurements and use averages to get rid of single sample anomalies, but I didn't, too late now). Take the below with grain of salt...

1691667537012.png


As said, not very exact science but clearly something changed for better :o). Now the noise is much more tolerable, and closing the door gets rid of the hum, which wasn't the case before the fix.

In summary, I don't say it is perfect, but compared to previous the change is definitely a big improvement and I can live with it now! Still I keep wondering how my 13kW inverter back home doesn't need any fans, just convection cooling and zero noise.


1691667537012.png (24.0 KiB)
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klaus78 avatar image
klaus78 answered ·

Hi all, is anyone happy with the fan modifcation (noctua)? You can read that the original fan gets replaced by noctua 2000/3000, but I am not sure if this is the major solution.

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Rob Duthie avatar image
Rob Duthie answered ·

Hi

Install the free fan upgrade kit from Victron works very well and much quiter now.

Regards
Rob D

NZ

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graham-willsher avatar image graham-willsher commented ·

Hi @Rob Duthie,

Please excuse the long post.

I have been following this tread with interest, as I like others have a ‘noisy’ inverter.

My set up is comprised of a Multiplus II 48/5000 GX and a Multiplus II 48 /5000 in parallel, as originally I wasn’t going to have batteries, and then decided to increase my battery capacity from 3 Pylontech US500 to 8 US500’s and it was cheaper to have a second inverter rather than replace the original inverter with a single larger one.

Both units are in a garage that is physically connected to my house, and when under full load (simultaneously charging the batteries and charging my EV) the noise from the non GX inverter is quite something, both the electrical humming and the fan noise.

The curious thing is that the non GX version of the inverter is much noisier than the GX version. Both have the newer serial numbers so the upgrade kit is not available for them.

My question is when you upgrade the installed fan to the Noctua one (+ capacitor) do you also include rubber noise damping grommets to help isolate the case wherever you fasten it to a wall?

You mentioned that to change the fan it is easier to remove the unit from the wall, so my thought was to change both the fan and install grommets are the same time.

As per your previous comments (and others) this is only trying to mask the under lying problem of electrical acoustics and fan issues. It would be good if Victron would look into this for a ‘approved’ change of fan for those who want it, but take the comments to heart when they are working on the Multiplus III and address the acoustics and fan issues at the design stage, to build a better product.

If you can think of anything else, or have any other advice that I should be thinking about when doing this work it would be appreciated.

Thanks,

Graham.

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beat avatar image beat graham-willsher commented ·

@graham Willsher Also make sure to have the latest firmware in the MultiPlus II. For some serial numbers, v507+ makes a big difference in fan noise. It did for me. No changes on transformer noise.

But Damping the mounting (beware to have no direct solid contact) does change a lot the noise in nearby rooms, and quite a bit in the room itself.

BTW: beware that upgrading MP-II firmware erases its configuration, so you need to follow the upgrade steps exactly (and a Windows PC is required to upgrade the configuration before restoring it). I did last upgrades with VRM, and it worked fine, following very exactly the steps, but read all the warnings and steps carefully.

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Rob Duthie avatar image Rob Duthie graham-willsher commented ·
Hi

It depends on the fan noise, as some new serial numbers might have being missed?

The fan noise is quite a pulsing sound at slow speeds, with the fan mod kit from Victron it is much very much reduced and quite at low speed now, You can still be get a ungrade kit regardless. As it might be still be a unit that did not get the mod done in the factory.

The muliplus can have a electrical noise from the internal toroid transfomer when running certian loads with a DC component, eg hair dryers, heat guns with SCR control speed etc, EV are usually very good as they have good filters in the charger unit in the car.

Yes i fitted vibration dampers in as well as change the fan, to improve the fan noise issues , but removed then and fitted the orginal fan back and fitted the mod kit, to a much quiter system now.

Regards

Rob D

NZ

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graham-willsher avatar image graham-willsher Rob Duthie commented ·
Hi @Rob Duthie,

Thanks for your reply.

I will ask my distributor to order the retrofit kits, and hopefully this will help.

Thanks for your help with this.

Graham.

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beat avatar image beat graham-willsher commented ·
And yes, if Victron could approve the mod for Noctua fans, it would be awesome.

But I'm afraid that without any fan noise, the transformer noise will be seeming even noisier lol.

My bet is that future MP-III will be "RS"-type with smaller high frequency transformers, but I then really hope that Victron will be damping fan mounts and if possible use the Noctua industrial ones, it makes a huge difference.
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graham-willsher avatar image graham-willsher beat commented ·
Hi @beat,

Thanks for your reply.

Retrofit kits are going to be ordered. I will probably install acoustic damping grommets at the same time so that I don't have to keep removing the unit from it's mounted position.

As you mentioned, hopefully, in Multiplus III Vicrton will address these issues at the design stage

Thanks,

Graham.

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maa avatar image maa graham-willsher commented ·
Hello,

Can you take somme pictures of this retrofit kit please?

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ppr avatar image
ppr answered ·

I just got MP II 8000. I def. plan to print a mount to fit a 140mm 2000rpm noctua for the left fan. and I try to do the same for the right fan for the power electronics.
Has anyone tried to mount bitumen mates on the blue Cover - additional.
And does anyone know what the left fan is for? I doubt that the NA relais need them? Just to blow a bit air around?
Thank you for your hints.

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