question

edgargw22 avatar image
edgargw22 asked

Multiplus flutters with coffee maker

I have a Multiplus 12/3000/120-50 Inverter/Charger that makes a fluttering sound when it's inverting about every 40 seconds when my Keurig Coffee Maker is ON.

Any ideas why this happens. TIA.

Multiplus-II
12 comments
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dangermouse avatar image dangermouse commented ·

i have the same issue with a nespresso,


i have 24/3000/70 multi

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edgargw22 avatar image edgargw22 dangermouse commented ·

I feels good knowing that I'm not the only one. Thanks for posting this.

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edgargw22 avatar image edgargw22 dangermouse commented ·

Can you listen to the sound file that I added yo this post? Is it the same sound that you hear?

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treejohnny avatar image treejohnny commented ·

My Multiplus 24/3000 will do the same with a 400 watt load on it. If the load is more or less it will go away. My noise is not the fan.

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edgargw22 avatar image edgargw22 commented ·

Attached, please find a sound file that I recorded with my iPhone.ClickingNoise.m4a

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clickingnoise.m4a (72.6 KiB)
boekel avatar image boekel ♦ edgargw22 commented ·

That's from the Multi? doesn't sound good indeed.

I'd contact an installer to see if he / she can read any errors from the unit, and then see what action is needed.

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Paul B avatar image Paul B boekel ♦ commented ·

I agree with Boekel it does not sound very good

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joed avatar image joed commented ·

mine does the same thing with my keurig plugged in-- funny your post is from 2 years ago and the problem still persists- i narrowed it down by unplugging each appliance until that same noise quit. when it did happen the voltage dropped to 117 from 120 every 30 seconds it would make that growl sound


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Alexandra avatar image Alexandra ♦ joed commented ·

@joed

The problem os not the Victron but the appliances use of a triac for speed control.

Just google triac and nespresso and you will find a replacement board with the device on it. The veey operation of a triac is to chop the frequency of the AC sine wave.

Any device using this for speed control from washing machines to air conditioners, hair dryers and various other appliances cause this issue. The problem exists even on other inverters. So the conclusion is not a Victron problem but an appliance mode of operation problem.

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edgargw22 avatar image edgargw22 Alexandra ♦ commented ·

It's still occuring so I keep my coffee maker off most of the time. My dealer tested the same inverter and a similair Keurig model in thier lab and was not able to reproduce the problem, so the simple and cheapest fix for me is to just replace the coffee maker.

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Alexandra avatar image Alexandra ♦ joed commented ·

@joed

Check your ground neutral connection or your ground relay settings. if it is the same relay clicking you are hearing as the recording.

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jeffryk avatar image jeffryk commented ·
I just finished my installation and have this same issue. From reading this thread it seems to indicate there is nothing wrong with the Multiplus, rather the appliances drawing power. Is this a correct statement?
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7 Answers
kai avatar image
kai answered ·

It may be just the fan in the MP turning at a higher speed when the coffee maker turns its internals (e.g. heating element) on. The fan speed changes depending on load.



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sean avatar image
sean answered ·

To me, that sounds like relay chatter.

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alan avatar image
alan answered ·

My Nespresso doesn’t like the frequency shift from the multi, specifically the water pump. It will barely pump any water, turning on a load or switching off the fronius allows the frequency to drop then it functions fine. I have also heard the relay flutter once or twice.


My guess is that it has something to do with the uneven current draw of the vibrating pump inside the coffee machine. https://youtu.be/we9IZJ5tQFs

These pumps generally only draw current on the positive side of the AC waveform.

As to what’s going on in the relay/multi that would be best answered by someone at victron.


The coffee machine is the only thing I have ever had any trouble running on my system, and generally when I want coffee in the morning the frequency shift hasn’t kicked in yet.

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kai avatar image
kai answered ·

The recording is similar to the noise I hear from my unit. I did a test and am pretty sure it is coming from the fan function (whether its the fan itself or something in the electrical path).

Tested by adding the silent fan assistant via VEConfig. When I did it, the fan didn't start up and neither did the clicking sound. I kept an eye on this for close to an hour - no clicking sound at all (normally I would expect to hear the clicking sound intermittently).

I speculate its coming from the fan being PWM'd, and in particular at low duty cycles there's some odd interaction between the PWM waveforms and the fan, causing the sound. I hear the clicking when the unit is just starting up cold (fan being spun at lower RPMs presumably). Then it becomes sporadic. When the fan is going full-bore I don't hear it - again presumably at 100% DC the fan is just on, not being PWM'd.

This also fits in with other comments indicating that its not typical. The interaction is likely to be quite specific to the actual fan in the unit (maybe different mfg, different batch etc).


If anyone else that hears the clicking noise also have VEConfig on hand, would be interesting if you did a test and report back :)


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wkirby avatar image wkirby ♦♦ commented ·

That's an interesting observation.
The fan doesn't just turn on with a temperature condition, it turns on at certain inverter power levels too. Certain appliances use horrid half-wave rectifiers which will cause havoc as there will be a high power demand on only one half of the output waveform. This could well confuse the control loop for the fan's PWM control.

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moonlightrider avatar image moonlightrider commented ·

I would rule out being the fan.

My guess is that those loads create too much wave distortion/harmonics for the unit to coupe with, probably, there's also some lights flickering (AC out) when the inverter makes that noise.

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edgargw22 avatar image edgargw22 moonlightrider commented ·

Yes, the LED lights inside the rig flicker. That was my first indication there was something else going on.

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John Rushworth avatar image
John Rushworth answered ·

Just a note to say my friend uses a Nespresso and I haven’t noticed an issue. I think his is a 48V 5000.

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Kevin Windrem avatar image
Kevin Windrem answered ·

I have a Nespresso and it cycles the heating element rapidly to maintain the temperature. I'd originally had issues with the Multi Compact keeping up with the load change (1200 watts to 0 watts). My last trip in my RV the problem did seem better than before. I did NOT hear the clicking noise reported by others.

Devices that draw currents on only one half of the waveform do place a strain on inverters in general. Many have reported problems with heat guns on the low setting when using them as a test load.

I don't think the water pump in a coffee maker draws enough current (even if it's on only one half of the AC waveform) to cause issues.

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jeffryk avatar image
jeffryk answered ·

Testing yesterday, I can confirm that a new coffee maker (Keurig) does not cause the inverter to make this noise. A hairdryer on high does not make the noise but switching to low the inverter does begin to make the noise. The question still remains exactly what inside the inverter is making this noise and could it cause damage over time to the invert?

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Kevin Windrem avatar image Kevin Windrem commented ·
Hair driers often use a diode to reduce power do only draw power from one half of the sine wave. This represents a load which varies every 1/120 of a second (or 1/100 for 50 Hz).

Some coffee makers do a similar thing at a much slower rate, say several times a second.

The transformer inside the Multi/Quatro is most likely what is making the noise.

As for damage, Victron would need to provide that information.

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jeffryk avatar image jeffryk Kevin Windrem commented ·
Kevin, thanks for the information. I would love to get direct feedback from Victron, but it appears they do not provide any support directly, only through distributors and currently I am not getting any help from that route. The last suggestion they had was to make sure there is nothing loose inside the unit. Not a terribly helpful response! If you or anyone else here on the community can let me know if it is at all possible to get help from Victron direct please let me know how to do that.
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Kevin Windrem avatar image Kevin Windrem jeffryk commented ·
This forum is the best place to ask for guidance. Victron staff visit here often.


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jeffryk avatar image jeffryk commented ·

One further bit of information. The clicking noise also happens when the microwave is running, the microwave is an older unit about 15 years old. More strangely when running the air conditioning unit which is a 3-year-old Dometic 12,000 BTU unit, it also makes this clicking sound.

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