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sparkpoint-solar avatar image
sparkpoint-solar asked

Victron Inverters not compatible with appliances that don't use the full AC power cycle???!!!

We have seen reports of Victron Inverters not being compatible with appliances such as hair straighteners, and hair dryers on the low setting.
https://community.victronenergy.com/questions/153259/multiplus-121200-clicking-with-hair-straighteners.html

We can confirm this behavior on
-Victron Multiplus 12V 1600VA and
-Victron Multiplus 24V 3000VA (can be seen in the attached video).


The lack of an answer from a Victron representative so far is disappointing. I really don't know what to tell our customers. "Please bear in mind that Victron Inverters are not compatible with certain devices such as hair straighteners." or "You can continue using your hair straightener even though the inverter makes a scary noise, it won't damage the inverter." ???

Victron is the brand we currently recommend most, but unanswered issues like this erode that position.


MultiPlus Quattro Inverter Charger
whatsapp-video-2022-11-19-at-73014-pm.mp4 (2.5 MiB)
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4 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @SparkPoint Solar,

The main issues I have seen is unexpected overloads - there is an explanation for why this occurs here - https://community.victronenergy.com/questions/61525/pheonix-122000-and-hair-dryers.html

I haven't heard of any damage or warranty issues, but it stands to reason that it's a 'harsh' load for the inverter to run, likely to cause considerable DC ripple (see https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf ) and beyond 'normal' cycling of components.

I'd personally try to find appliances that don't cause the effect, or minimise the use of them, but it's not a strict limitation that you cannot run them (unless they prevent you due to overload as in the case above).

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johnone avatar image johnone commented ·

IMHO that's not a good enough response from Victron. Not sure when the penny is going to drop re inverter noise but just to give it another try: given the energy crisis, the consumer market for inverters is changing (in the UK at least) as people look for ways to save money and be more energy efficient. Lots of people are installing energy storage systems in their homes. The newer Chinese manufacturers are making near-silent inverters - they now show noise data such as <25db. Meanwhile, Victron don't seem to be interested as shown by the 'expert answer' below (how could Victron Community class that as an 'expert' answer?) and by Guy's techie response. Surely you can't feel insulted or whatever by the techie label - do you really believe that the reseller above can tell his customers to avoid DC ripple appliances?

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nickdb avatar image nickdb ♦♦ johnone commented ·

@Johnone the conventional multiplus is a low frequency (transformer based) inverter - these will have issues with cheap appliances that use a partial cycle.

The smaller the inverter the more likely it is to be a problem (overload).

The fong kong inverters are high-frequency inverters and they deal with these loads better.

Victron's new RS range are also HF and are very quiet as well, so you're not comparing apples with apples.

The new multis are now also much quieter, none of this is news nor should it be news to anyone who does this for a living.




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sparkpoint-solar avatar image sparkpoint-solar commented ·

Thank you for your prompt response @Guy Stewart (Victron Community Manager) . We will tell our clients to find appliances that don't cause the effect. However I disagree that it is not a strict limitation... We tested this again on a Victron 48V 1200VA Phoenix Inverter, with a set of 150W hair straighteners and it causes the Inverter to shutdown on overload.

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nickdb avatar image nickdb ♦♦ sparkpoint-solar commented ·
Yes because it is trying to extract that power from a small piece of the cycle that is incapable of delivering it. Do the same on a larger inverter and it should be fine.

If you’re delivering < 1000W across a full cycle, there is only so much that can be delivered from a much smaller slice.

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marekp avatar image
marekp answered ·

If noise is your only concern I woud not worry about it.

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ahtrimble avatar image
ahtrimble answered ·

We run a 5kw Quattro on the house and wife uses a hair straightener and a hair blower...we have no problems. On my remote shop I run a cheap China inverter that is HF. That China inverter has burned out a HF battery charger and my other HF battery chargers are damaged. Because, as I found out later, HF inverters and HF battery charges don't play well together.

Based on the wattage of the inverters you mentioned and the power requirement of the hair straightener, I would say you are pushing the upper limit of the inverter itself, depending on the other loads at the time. From a practical perspective...I would say get rid of, or replace, the hair straightener...it is far less important than the inverter in the bigger picture. Conversely, matching the proper inverter to load requirements is always an option.

As for your statement "...newer Chinese manufacturers..." I can tell you that this is a fallacy. I have installed older and newer China made inverters...and regret virtually all of them. Trying to compare them to Victron units is a mistake. Understanding Victron units and properly matching that equipment to specific needs/requirements is the key. And that comes from my personal experience.

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david00 avatar image
david00 answered ·

There are a few posts like this one, where Victron seems to be avoiding addressing the root cause or attributing it to “cheap” electrical appliances.

I have a Phoenix 24/3000w inverter, and reported an issue to Victron 4 or 5 years ago with various appliances. The most obvious scenario was when my wife used her (not cheap) GHD hair straighteners. I also posted on the community - but my post seems to have disappeared.

When the hair straighteners are switched on, the inverter vibrates - it sounds like a muffled hammer drill. But still very noisy.

This has nothing to do with the appliance in question using more power than the inverter can supply, which seems to be Victron’s stock answer. Or DC ripple. Or any other excuse. It is that the GHDs, plus many other domestic appliances, use some kind of phase control.

Victron’s own “Wiring Unlimited” PDF on the web has a section on “Non Linear” loads showing phase control, saying “When an inverter powers a non-linear load, it may experience an overload situation sooner than expected based on the power rating of the load and the inverter”.

"It may" should perhaps be read as "it will".

Just to confirm this, I wired a standard household light dimmer switch to a 100w tungsten filament light bulb. As I adjusted the brightness of the light, the inverter made a lot of noise and its power output was choppy - with no other loads connected. When I added a diode in series so that only one half of the AC cycle would be used, it was even worse.

There is protection circuitry in the inverter that is comparing power within each cycle - probably related to detecting high inrush current from inductive loads - to determine if there is some kind of instantaneous overload.

As noted elsewhere, a number of domestic appliance that have a heating element - like hair straighteners, coffee machines, etc - are likely to employ phase control using electronic devices like triacs and thyristors.

While these sorts of appliances may not damage the inverter, they cause it to generate a choppy output. This has the potential to damage other more sensitive electronic appliances that are also connected to the inverter.

It would be great if someone from Victor could be honest about the issue and the fact that some types of low power appliances can cause the inverter to operate out of regulation, with the risk of consequential damage. But I’m guessing that one will want to admit to this, or advise on whether this has been fixed in later models...


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Phil Gavin avatar image Phil Gavin commented ·

A Low-frequency device is transformer-based. A transformer is an inductor and, as such, does not respond well to step changes in current. This means the semi-conductor switched loads you describe.

This is a law of physics that comes along with a transformer (electromagnetism). This is the root cause; it can no more be addressed than the nuisance problem of "gravity".

It exists. It isn't a mystery.

There are inverters that do not use this technology, but they may not have the advantages that a low-frequency transformer-based design has.

A utility power grid also uses transformers, but consumers are blissfully unaware of this phenomenon because their hairdryer is swamped by all the other full cycle loads that make up the vast percentage of the loading of the far bigger grid transformer.

Having been involved with power quality studies at a grid level, I have seen an instance where a high industrial non-linear load had this effect on grid transformers. The utility insisted that the customer limit/remove these loads from the grid as this caused flicker to other customers in the same locale.

Now back to your relatively tiny inverter:

A single appliance represents a greater % of the full load to a smaller inverter than a larger one. Therefore, a smaller model inverter will be more prone to display symptoms. So the use of the word "may" is not misplaced. It is entirely based on the switch load's relative size to the inverter and its other non-switched loads.

Or, of course, use these offending appliances at full power.

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nickdb avatar image nickdb ♦♦ Phil Gavin commented ·

Yip. HF, transformerless inverters like Victron's RS won't show this behaviour.

Some people get offended by referring to these appliances as cheap, and to be fair some pretty expensive products have the same behaviour, simply because the manufacturer has chosen to use a pretty cheap method of power control.

It is unfortunately physics.

Had this recently myself with a site that had a "cost effective" travel hairdryer. It resolved by using it on full power.

Not much that low frequency inverters can do about it until someone works out how to adjust physics via firmware. :)


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Alexandra avatar image Alexandra ♦ nickdb ♦♦ commented ·

Yes, with other loads on you also 'may not' have an early overload warnings. Wiring unlimited is correct there.

The overloads do not always happen. The sound can be minimised with other loads taking up the 'noise'.

People are now just more aware of these issues that the grid used to absorb since they now hear their tiny grids struggling.

@Phil Gavin, I enjoyed reading about the experience. Thanks for the share.

Sincerely

cheap hair dryer and straightener user.... From 2012.

BTW problem is "solved" with the RS series of inverters as expected. Bought a new inverter rather than replace the offending (but sentimental) hair gadgets.

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david00 avatar image david00 nickdb ♦♦ commented ·

@nickdb - Heating elements can use an on/off duty cycle to maintain a certain temp. But I'd argue that is the "cheaper" approach.

Phase control is sometimes the only option - such as for lighting dimmers. And it achieves more precise power control than an on/off approach that usually has hysteresis.

Is there another approach you are thinking of, that appliance manufacturers should be using?

I’ll take a look at the RS series, thx for the info.

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david00 avatar image david00 Phil Gavin commented ·

@Phil Gavin

Yes, inductors don’t like a sudden change to their current. Phase control has that effect, and can also lead to higher-order harmonics. But does significant phase control cause flicker at grid level? Flicker tends to be related to a voltage drop due to large reactive loads (another category of non-linear load) or high-current loads coming online.

However, phase control is taking place at 50/100 Hz (in Europe). So you would normally expect any impact of this to be at that frequency - or multiples due to harmonics.

When I connect an appliance that is using phase control, like my wife’s GHDs, there’s a banging noise at around 6 Hz from the inverter (its transformer). Loud enough to hear through brick walls. Hence my assumption that there is some protection circuitry within the inverter that is sensing unusual current transitions and incorrectly assuming there is an instantaneous overload and tripping out. What else would cause banging at this low frequency?

With my 100 W light bulb test circuit, if I also connect a higher power appliance like a fridge then the compressor motor is intermittent and the door light flickers on and off - I haven’t been able to look at this on a scope, but it’s clear that the inverter is running way out of regulation.

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