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Craig Myatt avatar image
Craig Myatt asked

Measuring PV output, into a Venus device, for Enphase microinverters

I will be doing a system with a MultiplusII, AC coupled to several strings of Enphase micro inverters. I want to measure the PV input, as data into the VenusGX, from the microinveters. I have spec'd an ET112 meter to do that, but I presume that might not work...eg putting mutliple active wires (from each PV string) through the meter doesn't sound like a good idea. perhaps a 3phase meter, setup to read 3 strings? Or is there enphase support (sunspec standard?) on Venus devices yet? Is anyone familiar with the enphase envoy? Perhaps enphase has a solution...

Venus GX - VGXAC PV Coupling
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Paul B avatar image
Paul B answered ·

Get a Victron AC sensor and put that on the output of the PV inverters conect it to the Aux output on the inverter, if there are not enough then you may need a external board to add it, setup a Assistant and the the PV tile will appear on the CCGX and thus also in the VRM report

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Craig Myatt avatar image Craig Myatt commented ·

I think that will work, just wasn't sure that the AC sensor would work with the Multiplus-II, however, apparently so. Via the Aux input? If that is so, then I think with the strings coming together, as noted by WKirby, then I should be OK with one AC Sensor, going into the Multiplus-II, unless putting it into the Venus GX would work. Thanks Paul.

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wkirby avatar image
wkirby answered ·

I have an Enphase M215 in my system.
I am using a Carlo Gavazzi EM111 to measure its output. I have the EM111 connected to my Venus system and then tell the system that the EM111 is a PV meter.

What is the peak power that your Enphase "farm" can produce? The ET112 can measure 100A on a single phase so unless your system is more than 24KW (240V) or 12KW (120V) then it will be perfect.

Surely you are using the Enphase cbling to connect the microinverters together and that they meet up at some point in the system? At this point, or the feed to the distribution board would be a good place to site the ET112.

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Craig Myatt avatar image Craig Myatt commented ·

Thanks for that...am looking at the ET340 3phase as well...which apparently can be setup to do grid & PV monitoring, as single phase...so I think that is the way to go.

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wkirby avatar image wkirby ♦♦ Craig Myatt commented ·

Yes, that is a good solution.
I have been meaning to look into the SunSpec specification, but I have always had something better to do. It would be good if the Enphase systems could be integrated into Venus.

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Craig Myatt avatar image Craig Myatt commented ·

The peak of the output is about 3.2KW, I think. But I am planning to put the Multiplus in so that it is AC coupled, on the AC output, which means we may/will have a problem with overcharging+excessPV, when/if the system is disconnected from the grid. Occasional grid disconnection was the whole point of the system...as a grid backup.

What the solution normally would be, eg Fronius inverters, is frequency shifting, indicating to the inverter to throttle back output. Enphase don't recommend relying on this however. So at this point, I plan to use a basic relay which actuates if Grid is down+batteries are full, shunting out the Mircoinverters. There is also an Enphase device which does this, but not sure how I could literally actuate that, as and when needed. I was a bit concerned that simply shutting the AC off in this way, using a relay may not be ideal...would you have any concerns about that approach?

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perma-batteries avatar image perma-batteries Craig Myatt commented ·

Based on a technical whitepaper published by ENPHASE named "Design Considerations When AC Coupling IQ Micros to Battery-Based Systems", it seems like the IQ7 can support FSPC in micro-grid, AC coupled systems to battery based inverters. Grid profile in the envoy system should be manually set-up though. https://enphase.com/sites/default/files/downloads/support/Design-Considerations-AC-Coupling-Micros-Battery.pdf

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russ avatar image
russ answered ·

i am planning to setup similar using renesola microinverters. (not recommended by the way but i have them)

the approach renesola recommended was to set the cutoff frequency in each to a different point, eg, 50.2, 50,3, 50,4 etc, so that in the event grid is lost and there is excess production, it will ramp down progressively rather than drop suddenly.

(then i discovered i needed multiplus II... :(


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mr-manuel answered ·

If you additionally want to see the PV input in Venus OS using the data from your Envoy-S you can use this driver: https://github.com/mr-manuel/venus-os_dbus-enphase-envoy

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