Grid Goes down; Multiple Inverters; Combine SPS into transfer switch

[Mike90250]

Thanks for the responses everyone. Here is something that is a little bit confusing to me.

What is the difference between:
A) 5x split phase 240v AC output inverters wired into a combiner box then out to the load.
B) 5x 240v AC output SPS' wired into a combiner box then out to the load.

I can't find a good reason why A would work but B would not work. Thoughts?

> A) 5x split phase 240v AC output inverters wired into a combiner box then out to the load.
Will only work with 240V loads, those inverters use a neutral wire for reference, not for load balance ( from what little I know about microinverters)


> B) 5x 240v AC output SPS' wired into a combiner box then out to the load.
SPS' don't have a Sync signal, so you will have: (in order of likelihood)
a) smoke
b) 5 random phases
c) might get super lucky and some would sync together somehow

[solardreamer]

Thanks for the responses everyone. Here is something that is a little bit confusing to me.

What is the difference between:
A) 5x split phase 240v AC output inverters wired into a combiner box then out to the load.
B) 5x 240v AC output SPS' wired into a combiner box then out to the load.

I can't find a good reason why A would work but B would not work. Thoughts?

A) works for grid-tied inverters because they sync to an independent grid voltage waveform. B) does not work because they don't sync to anything.

[solardreamer]

I have seen that video. Anything is possible on Youtube. It is an interesting science experiment and I am surprised it has only received 100 views considering how many schemes go viral on Youtube. It is not sustainable because the H6 is a dead end inverter with no support. That video does nothing to address the complexities of powering an electrical device with solar. I have reach that conclusion after many hours of watching Youtube videos.

H6 definitely is dead end and no support. There is also E5 that has support but not available in the US yet.

[SoftwareDude]

A) works for grid-tied inverters because they sync to an independent grid voltage waveform. B) does not work because they don't sync to anything.

Ah... That makes sense. Thanks for that.

[SoftwareDude]

A) works for grid-tied inverters because they sync to an independent grid voltage waveform. B) does not work because they don't sync to anything.

Is there something you can buy to sync them so that you can essentially combine them into a 240v plug and plug it into a transfer switch?

[oregon_phil]

B) No. Have you read the SMA inverter manual or searched the web regarding SPS functionality?

SMA inverters using the SPS outlet require GFCI outlets. One hint of abnormal loads or loads too high, the SPS outlet will shutdown. I have one and it is picky.

Combining SPS outlets from multiple inverter will not work. It will violate warranties. It won't work. Time to move on.

[SoftwareDude]

B) No. Have you read the SMA inverter manual or searched the web regarding SPS functionality?

SMA inverters using the SPS outlet require GFCI outlets. One hint of abnormal loads or loads too high, the SPS outlet will shutdown. I have one and it is picky.

Combining SPS outlets from multiple inverter will not work. It will violate warranties. It won't work. Time to move on.

I appreciate the comment. I am not disagreeing with you, but I will decide to move on once I am satisfied that the answer is no. That's why I am asking a group of people and not just one person.

[solardreamer]

Is there something you can buy to sync them so that you can essentially combine them into a 240v plug and plug it into a transfer switch?

I am not aware of anything plug-n-play for B). It's possible to convert each SPS output to DC then combine them to power another inverter kind of like a double-conversion UPS but is it worth doing?

[solarix]

"A) 5x split phase 240v AC output inverters wired into a combiner box then out to the load." Doesn't work either. You can't run a microinverter into a load unless it is grid tied...Even if you are talking about battery backed inverters, you can't tie their outputs together.

[khanh dam]

It seems like a lot of work for TIGO to keep validating whether or not their modules work with SMA SPS functionality so I would expect TIGO to stop this work for new inverters.

I called Tigo and their rep basically said we wont' test it because we dont' have the gear, but if you want to test it and let us know that would be great. In other words you are on your own with zero support.

[khanh dam]

Ah... That makes sense. Thanks for that.

SPS is dead end technology because SMA no longer supports it On A RESIDENTIAL HOME which requires rapdi shut down. Only way to get around that is to build solar array on a pergola/detached unoccupied building so no rapid shut down is required. Building a structure big enough for your needs is at least another $6K DIY or $15K if you hire someone to make it.

SMA did release a white paper for using 2 nine volt batteries to power the transmitter while the grid was down a few years ago. If you are smart you might be able to figgure how to use with TIGO , but frankly thsi whole idea of paralleling all the outputs is a little daf. Just run the 5 SPS outlets to five parts of your home with extention cords as needed for the once a year emergency.