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johnone avatar image
johnone Suspended asked

Alternatives to Multiplus for domestic ESS

I'm one of the many currently jumping into installing ESS given energy prices/ want to be more sustainable. Attracted to Victron given sophisticated control via Cerbo GX and open source (we have RPi-based BMS). Kit now arrived - holy cow, the Multiplus II is one agricultural piece of metal. There's no wonder people on here occasionally mention the elephant in the room - noise. Buzzing, humming and the fan-on-steriods, all amplified by the steel box. The Multiplus II is not designed to be domestic kit. So, what are the alternatives - transformer-less, fan-less hybrid inverters designed for the domestic market which will talk to the neat Victron control units. Has anyone any experience of using other manufacturers' hybrid inverters with Victron control kit?

Multiplus-II
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wkirby avatar image
wkirby answered ·

The Multi RS is a high frequency topology, light weight, powerful and quiet even at full chat.
However, ESS is not yet available and network approvals have not been attained for grid parallel operation. It works very well in standard mode, only connecting to the network to charge during off peak rates for example.

No third party hybrid inverters work with the CerboGX. You'd be very hard pressed to find a manufacturer who is willing to develop their systems to work with a competitors products one way or the other. PV inverters from other manufacturers do work, but Victron don't have any of these in their own lineup so no competition.

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johnone avatar image
johnone answered ·

1."ESS is not yet available" - Victron say (in numerous places): "the MultiPlus-II is the key component in a Victron ESS system"
2. "network approvals have not been attained" - less said about this the better!
3. "It works very well in standard mode, only connecting to the network to charge during off peak rates for example" - looking at the fine detail in ENA EREC G99, connecting a device which is capable of export (merely by changing settings) would seem to mean it would need DNO approval.

Back to the noise issue, we'll see how bad it is and have the fall-back of putting it in an attached garage. I'd prefer not to. Is it really the case that "No third party hybrid inverters work with the CerboGX"? Be in Victron's interests as it'll take some time for them to develop a hybrid inverter to compete with the many new Chinese models, which have gained Grid approval, and which are designed for the domestic market - put it in your hallway, that kind of thing.

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nickdb avatar image nickdb ♦♦ commented ·
The newer ones post hq2225 have much quieter fans. I have them in my own home, no issues. The older ones on the other hand were a bit much at times.

Wkirby was talking about the HF hybrid inverter, the RS, which victron has.

For ESS not available he referenced the RS model, which is quiet and has basic capabilities (no feedin etc).

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johnone avatar image johnone nickdb ♦♦ commented ·

Thanks. The Multiplus II will be screwed to the wall by the 4 corner fixing holes - i.e. not using the rail hook - with a 25mm rubber mat between it and the wall. Also, with front cover removed and a custom cover (not touching the unit's casing) fitted. The tightly fixed steel front seems to make the whole unit act like a drum, amplifying any hum etc. All ventialtion neeeds accounted for too. Hope the rubber isn't a fire risk (have seen otters on here say they use rubber spacers). I'll report back on noise levels, especially when charging 14kWh of batteries. Fingers crossed.

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nickdb avatar image nickdb ♦♦ johnone commented ·
What are the first four digits of your serial number? (After HQ).

The case does work as an acoustic amplifier. Lots of guys have made various mods, even swapping fans makes a difference. With rubber mounts and the new fan system it should be ok.


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johnone avatar image johnone nickdb ♦♦ commented ·

HQ2212 - arrived from supplier this week. img20221104170734.jpg

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peterthemoose avatar image peterthemoose johnone commented ·
Did anything help to solve loud huming issue? I just got 3 pcs. of Multiplus II 8000 installed and have the same problem. Serials are HQ2212 and 2213. Hear the noise all over the house even tough Multis are installed in the garage.
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johnone avatar image johnone peterthemoose commented ·

Hi @peterthemoose,

I've installed a Multiplus 5000 and as per advice from e.g. @nickdb :

1. got the supplier to replace a HQ2212 with a HQ2226 version (thus, less fan noise).

2. have mounted the device using the 4x corner fixings - not using the rail hook - and sandwiched a Screwfix 'Memory Foam Support Kneeling Mat' between it and the wall (see pic).

3. I've taken the hum-amplifying front cover off - the unit is (effectively) in its own (very well ventilated) cupboard in the attached garage, so can do without the front cover.

The result being that fan noise or hum isn't a problem at all. It's no louder than a freezer in the garage. At 2am in a v quiet rural area, when charging the 14kWh battery it's not silent but can't be heard at all in the kitchen (other side of the wall from the garage) or anywhere else in the house.

From posts on here, would seem that the grid supply and loads on the Multi can also be noise factors.img20221215123306.jpg

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peterthemoose avatar image peterthemoose johnone commented ·
Thank you very much for sharing your experience @Johnone It helps a lot.
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Craig Chamberlain avatar image Craig Chamberlain nickdb ♦♦ commented ·
@nickdb I just checked my Multiplus-II serial number and it's HQ2226 so I presume that means it has the improved noise performance. Can you clarify the nature of the noise improvements? Is it just to combat the transformer hum or is it the fan noise, or both?

I have my Multiplus-II 48/5000/70-50 mounted on a stud wall between our under stairs cupboard and my study where I work from home full time. I took the precaution of adding a sheet of 12mm plywood mounted to the existing plasterboard wall via 38mm battens, which are also positioned to provide timber fixings for the Multiplus mounting hook. I then added mineral wool insulation between plywood and plasterboard, as densely packed as possible. While it's certainly not silent, during the day when I'm working and loads are very light, there is no more of a hum from it than I hear from the standalone APC UPS I use to protect my computer equipment. If I boil the kettle then certainly the hum increases but then I can't hear it over the sound of a boiling kettle.

When I DO hear it is during battery charging at night (Octopus Go Faster 21:30-02:30hrs) when the fans spin up noticeably. I have the battery charge current reduced to 60A from the 70A maximum and that certainly helps but strangely, reducing it further to 50A actually made it noisier, perhaps due to some sort of resonance due to the PWM duty cycle being different.

My next step is to introduce some rubber couplings between MP and the wall, and perhaps also to line the inside of the cupboard with fire retardant acoustic panelling to help contain the fan noise. I might also look into active ventilation of the cupboard to reduce ambient temps during charging. They're well within spec at around 28C at floor level where the batteries are, and around 34C at high level and near 40C at the MP exhaust. These are peak temps during multi-hour charging sessions and so most of the day it's well below this. But if I can reduce that peak by 5-10C then even better.

Other things I want to consider is making that under stairs cupboard as fire resistant as possible by adding in fireboard and sealing up any gaps etc with intumescent sealer. I'll probably add a dedicated smoke alarm to the area too. I realise that LiFePo4 batteries are much safer than NMC but still - better safe than sorry.

Sorry to ramble on but just wanted to offer my own experience of the noise issue. I'm pretty sensitive to noise generally but I find it not too bad. I hate to think what it was like before the hardware improvements though. If the fans could be quietened further even better.

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wkirby avatar image wkirby ♦♦ commented ·

1. As nickdb kindly clarified, I was referring to the MultiRS not the MultiPlus II.
2. Again, I was referring to the MultiRS, maybe not even submitted for certification yet.
3. If it were a mere settings change or flick of a DIP switch accessible to the casual user, then yes. However there are (required) barriers in place in the form of a device firmware change requiring the deliberate use, in this case, of dedicated software, a programming dongle and protection by a complex password.

When a MultiPlus is connected to the network in standard mode it is not capable of feed in. It only operates as a charger and also passthrough to loads on AC output, similar to a UPS in a computer room. UPS' or a battery chargers do not require approval because they aren't capable of feed in.

Similarly, standard electric cars don't require any approval either even though a firmware alteration could make them V2G capable at a later time. Only if the car's firmware is altered to make it feed in capable then it would require the approvals. Cars would probably have a different approval standard from G99. I can imagine DNOs welcoming the prospect of evening time battery availability like a terrier would a welcome basin of lean mince.

Remember, there are a multitude of instances where inverter/chargers, like the MultiPlus, are employed in standard mode. Boats, caravans, motorhomes, coaches, emergency service vehicles, welfare buildings, outside broadcast vehicles, food vending outlets, kiosks and so forth, the list could go on. It would be most impractical for installations to require approval to feed in when they can't.

I dare say that there are probably more inverter/chargers around the world operating in standard mode than those operating in grid parallel mode.

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hominidae avatar image
hominidae answered ·

IMHO fan noise is only an issue if the inverters do not work behind closed doors.

What you defnitely need is some kind of structure-borne sound isolation...You can use anchors/dowels from sanitary installations (rubber mantled dowels) and also place a standard hard rubber pad (like a terrace pad, approx 10-20mm thick) between unit and wall for each mounting hole.

Works wonders....I don't hear a thiing from my 3phase setup with 5000kVA Multipplus-II when in my living room, that sits right above the cellar room where these are mounted and whinning loud.

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johnone avatar image johnone commented ·

Thanks for sound isolation advice (see my comment above for what I'll try). Do you have a link to 'rubber mantled dowels'? Wondered about the supporting capacity of sanitary fixings.


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hominidae avatar image hominidae johnone commented ·

...see here (only in german, I am afraid): https://www.stabilo-sanitaer.de/schallschutzduebel-16-mm-ohne-bund/a-437146/ ...don't worry about the load these can carry...they are used for heavy washing basins and such. ... you should be able to source these or alike in your local DIY shop or online

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wkirby avatar image wkirby ♦♦ johnone commented ·

These kind on things?

1667584747886.png

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johnone avatar image johnone wkirby ♦♦ commented ·

The sound insulation dowels @Hominidae mentions look good but I can't find them in the UK (only an Amazon UK seller, who's sold out). Maybe we should join the EU. The anti vibration bobbins also look good - could core drill holes in the wall (brick in my case), and set the bobbins in resin (Everbuild Anchorset, that sort of thing). Is that what you were thinking?


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wkirby avatar image wkirby ♦♦ johnone commented ·

RS (you can't get more British than that) sell anti vibration mounts too.

https://uk.rs-online.com/web/c/?searchTerm=anti+vibration+mount

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hominidae avatar image hominidae johnone commented ·
The manufacturer has it's own online Shop and is also to be found on eBay....wonder if they would ship internationally. But I also can't think, that there is no other manufacturer/ source of these. As said, I got mine in a local DIY shop (Germany though).
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dancrompton avatar image dancrompton johnone commented ·

These might do the trick.

https://rawlplug.co.uk/product/rawlnut-flexi-plug-with-screw/

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dancrompton avatar image
dancrompton answered ·
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