Will Hoymiles microinverters work in off-grid mode with a MultiPlus-II?

DIY
, ,
1

Hello,

I currently have a grid-tied solar system using Hoymiles microinverters (AC-coupled). I’m considering installing a Victron MultiPlus-II with batteries to add backup capability and possibly operate in off-grid (island) mode during grid outages.

My question is:
:orange_circle: Can Hoymiles microinverters continue to operate and feed power into the system when the MultiPlus-II is running in off-grid mode and forming the grid?

I understand that microinverters usually require a stable grid reference (230V / 50Hz) to operate and that not all inverters provide a signal accepted by anti-islanding protections.

Does the MultiPlus-II provide a sufficiently clean and stable grid reference to keep Hoymiles microinverters active in island mode?

Thanks in advance for your support and insights.

2

Yes,

Have Fun

Marc

3

Yes, they do. But they are not ideal, when it comes down to throttling through frequency shifting, iirc they won’t go bellow 50% power, but rather shut off to 0 then.

4

@dognose - can you tell more about it? I haven;t heard about this issue - that Hoymiles microinverters can’t gradually go down to zero via frequency shifting. If they can go only to 50% and then shut down then it is a real flaw.

5

Hello Bogi,

I have no idea how to measure this. But as a hint my frequency yesterday. (Pure sunshine):slight_smile:

IMG_9038
IMG_90381170×2532 186 KB

You see very nicely our tree :face_with_hand_over_mouth:

Now the part with frequency shift enlarged:

IMG_9040
IMG_90401170×2532 204 KB

May be this helps you.

System setup in my profile.

Have Fun

Marc

6

Thanks Marc. Maybe they also implemented rate-of-change monitoring. I can see the moment Victrons raised freq in big step Hoymiles reacted immediately and shut down. Wondering what will happen if frequency keeps increasing gradually, with no step changes.