Are micro invertors the future of residential installations?

[timselectric]

Right above the circled part, it says "grid parallel".
I wasn't aware of this capability from Victron.

 

[ncsolarelectric]

If they comply with UL1741SA or CA Rule 21 they have to work. They are on the CEC list for California so they must be able to be AC coupled. An inverter does not get on that list unless they comply with Rule 21.

What @Bluedog225 is referring to is controlling the output current. An inverter does not require export control to be CEC approved, but it requires it if it is to be used for utility-scale systems because the utilities require VAR control. The HM and HMS inverters, use a meter at the grid connection and RS485 to the DTU, so that it knows what the backfeed current is. It then sends curtailment commands to the inverters via Wifi or Sub-1G communication to keep the export at the level you set.

I've designed utility-interactive inverters that used a frequency/phase shift to send power to the battery, not to the grid. I used VAR control to generate a push back to the DC side of the inverter. It worked but it was a PITA to stabilize.

 

[fromport]

The multiplus has some frequency shifting capability. Not sure if it is sufficient to control micros.

Or I misunderstand. 50/50

View attachment 101080

You mentioned "victron multiplus" and I referenced the data sheet I used to see it does not have that ability.
Now you show that the "multiplus II" has something that refers to what would be needed.
Details matter, next time immediately mention "multiplus II" ?

 

[fromport]

I do not know any thing about the Multi-Plus except it would take two to produce split phase. It alludes so some frequency shifting capability and it describes the AC coupling process. It does not explicitly say AC coupling of list any limitations. Usually a hybrid inverter that can AC couple lists teh maximum GT inverter capacity that it can accomodate. Are there examples of people successfully AC coupling them? If so that may be a less inexpensive solution.

Like with the Enphase IQ7 there is a 150% PV wattage rating compared to the wattage of the battery inverter.
Only with the IQ8 they abandoned that ratio. I can image that Multiplus II has a maximum ratio PV vs DC power as well.
What if 10kW of PV suddenly wants to charge the battery of a 5kW inverter ?
more magic smoke...

 

[Ampster]

What @Bluedog225 is referring to is controlling the output current.

Yes, I think the output current of the grid dependent GT inverters would have to be controlled to reduce the power. Isn't that the required response per Rule 21 or Ul1741SA? Doesn't the voltage stay closer together?

 

[Ampster]

Like with the Enphase IQ7 there is a 150% PV wattage rating compared to the wattage of the battery inverter.

The limitation I was referring to was the limit of GT inverter capacity that can be AC coupled to a grid forming hybrid inverter. In the case of my Skybox it is 7.5kW regardless of the battery capacity of my 5 kW Skybox. That would be consistent with the rule but has nothing to do with Enphase. I am currently AC coupled to Enphase IQ7s but previously AC coupled to a SolarEdge and the Skybox had the same limitation. I am sure it would have the same limitation if it was AC coupled to IQ8s. As far as I know the Skybox relies on any GT inverter responding to frequency Watt per the Rule 21 spec.

 

[cs1234]

You mentioned "victron multiplus" and I referenced the data sheet I used to see it does not have that ability.
Now you show that the "multiplus II" has something that refers to what would be needed.
Details matter, next time immediately mention "multiplus II" ?

I was looking into this some more, and the regular Multiplus' should work.

They have to have an "assistant" installed on them, through this complicated procedure.

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/configuration.html
https://www.victronenergy.com/live/assistants:how_to_add_and_configure_an_assistant

I'm tempted to pick up one of the Victon Multiplus 24/3000 as it's one of the only UL1741 listed pieces of Victron equipment and it can supposedly do their frequency shift AC coupling as described in the links above. It's one of the least expensive STACKABLE "hybrid inverters" available, maybe, at $1500. I'm not sure if it requires a cerbo gx as well.

I'm all ears as to what other "low cost" options there are for stackable ac coupling capable inverters.

 

[BentleyJ]

I'm all ears as to what other "low cost" options there are for stackable ac coupling capable inverters.

Schneider SW 4024 or SW 4048.
4000watts, for around $1,500. Schneider SW and XW products have a built in AC charger but do not have built in MPPT solar charge controllers.

 

[cs1234]

Schneider SW 4024 or SW 4048.
4000watts, for around $1,500. Schneider SW and XW products have a built in AC charger but do not have built in MPPT solar charge controllers.

The Victron doesn't have built in MPPT either. The Victron Multiplus are stackable though, I don't think the lower cost SW line from Schneider is stackable. They do look like nice inverters though, both the SW and XW line.. and they have 48v models that are UL listed, unlike Victron.