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portsample avatar image
portsample asked

Possible to create a system in the US using Victron equipment that feeds excess power into the grid?

Is it possible under US regulations to create a photovoltaic and battery system using Victron components in the United States that feeds excess power back into the grid? My understanding is that Victron equipment is not UL approved. Are there any UL approved "pass-through" devices that might resolve concerns and allow the use of Victron devices to feed power back into the local area power grid? I am seeing lots of RVs, boats, and remote cabins with Victron systems in the US, but few systems for houses in rural and semi-rural areas.

installation
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ejrossouw avatar image ejrossouw commented ·

1680853490701.png

There are some models, The product pages will list certificates, if they have been certified.

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z-zk-z avatar image z-zk-z ejrossouw commented ·
Hey, Most people don't understand the difference between feeding power back to grid (aka net metering) and simply connecting to the grid (i.e., like as any load). I asked several other people and regardless of what others have replied to your post, Victron Multiplus II CANNOT feed power back to the grid. So, I recommend doing your own research instead of simply listening to others.
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derrick thomas avatar image derrick thomas z-zk-z commented ·
You may want to clarify your statement to prevent confusion to people reading this in the future. Although multiplus 2 may not be APPROVED for grid feedin in this or some other jurisdictions, it absolutely CAN feedin to the grid.
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portsample avatar image portsample derrick thomas commented ·

I HAVE been doing "research" via reading manual(s), Victron docs and Fronius docs. Appears that some, and perhaps all Multiplus II models can feed into the public grid. In the US, Multiplus devices had not been given gov't approval for this type of connection by the Underwriters Laboratory (UL) until very recently. Consequently, this niche (grid connected systems) has been filled by other devices (Sol-Ark, etc) and configurations (AC connected) in the US. Several US Victron installers as well as forum users have incorrectly stated that DC connected systems cannot feed power back into the grid, and that Victron equipment is only appropriate for off-grid applications, (boats, RVs, remote cabins, etc.). Currently, (to the best of my knowledge) only the MultiPlus-II 48/3000/35-50 120V model has received UL approval for US grids. Local authorities having jurisdiction (AHJ) may still not allow this device on their grids for a variety of reasons. One reseller has indicated that Victron Multipluses should not be used for grid connected systems as there is no onboard arc fault detection, ground fault detection, or rapid shutdown ability as does the Sol-Arc and some of the other one-box solutions engineered for the American market. Can anyone confirm this last statement regarding af/gf detection and rapid shutdown? TIA

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larsea-dk avatar image larsea-dk commented ·
Hi

I know this is not related to US, but I have a victron ess on grid with feedin excess in Denmark. It is extremely important to dimension your system right since Victron is quite difficulty to get to work properly with feedin excess. Works great if you do not feedin excess but is connected to grid. But feedin is as I see it not mature in realtion to control charge current to battery and control mppts.

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portsample avatar image portsample larsea-dk commented ·
This is good information. Thanks for posting. Some of the bigger solar installers in the US are refusing to install Victron grid connected systems, whereas others are. Good to know about the interface problem. Thanks again.
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larsea-dk avatar image larsea-dk portsample commented ·
If you feed in excess, the mppt charge current is not controlled. They will give full throttle and will only slow down very close to full battery(I think to near!!) since it do respect the max charge voltage IF AND ONLY IF you have enough units to handle the power to grid. I have only one multiplusII 48/5000 and have 7.5kWp panels, so I have not enough to take the power to grid and need to degrade my mppts max amps manually. In my country a single phase is also only allowed to feedin max 3,6kW which makes it even worse. The 48/5000 can deliver up to 4.5-5kW.
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Alexandra answered ·

@portsample

Yes it is. The real question is with local regs are you allowed to?

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z-zk-z avatar image
z-zk-z answered ·

Most power companies have a simple form online for requesting to feed power back to the grid. Of course, you need a meter that can run in both directions and the local building department will usually approve the installation via a permit. You also need a grid-tie inverter that monitors the power company waveforms and synchronizes with them, in addition to being able to disconnect automatically when the grid power goes down for safety. I know you can connect a Victron Multiplus-II to the grid but I believe it is meant to function as a load to the grid (like a refrigerator, light bulb, etc.) and not to feed power back to the grid. Please let me know if I am wrong when you find out more and which grid-tie inverter you decide to purchase.

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ejrossouw avatar image ejrossouw commented ·

The MP and Quattro range of inverters are all bi-directional and actually very well suited to many variations of grid-tie use "feeding back" energy via ACIN only as example. Having systems in the field of possibly every conceivable configuration you can imagine and many happily running alongside grid-tie PV systems as old as 10 years, my experience has only been very positive and without any headaches for my customers. I do not discount there may be complications in some case, but I have yet to experience it.

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portsample avatar image portsample commented ·

Checking the certification page here:

https://www.victronenergy.com/inverters-chargers/multiplus-ii#certificates

I found that the UL certificate for the MultiPlex II 48/3000/35-50 120V (MP2) was issued early last month. Question: Pardon my candor, but what goes between the MP2 and the grid? I suspect it is something (distribution box) to precisely match AC frequencies, etc. What is it? What brands/models are people using?

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ejrossouw avatar image ejrossouw portsample commented ·

The inverters sync with the grid as long as certain conditions are met, has integrated relays to disconnect from the grid in the event of grid loss, incorporates grid codes for a number of countries etc. and can be configured for use in many different ways.

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portsample avatar image portsample ejrossouw commented ·
Just for clarity are you talking about separate "grid-tie inverters", or are these components of the Multiplus itself? Thanks in advance.
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z-zk-z avatar image z-zk-z portsample commented ·

well, " MP and Quattro range of inverters are all bi-directional", those units must have the smarts built in for "precisely match AC frequencies, etc. ". You would (I guess, the code would require it) only need a mechanical disconnect just in case the grid tie unit fails to operate, also keep in mind that the grid connection in USA is 240 volts with a center tab (or 120V plus 120V). Isn't the grid voltage in Europe 240V with no center tab???

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ejrossouw avatar image ejrossouw z-zk-z commented ·

The units have integrated relays and some even two for redundancy as required for some certification. I am not familiar with the US models, but diagrams are available in the manuals which you can access with a lot of other information on the product pages. 1680907653077.png

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