Can the Sunsynk's be AC coupled on the inverter OUTPUT ?

[Delta9]

Hi guys,

Wondering if the Sunsynk Inverters can be AC coupled to the inverter OUTPUT - the same as the Victron inverters can be AC coupled to the output of the Victron's using a Fronius AC inverter? (even has the Fronius inverters in the victron menu system)

I think one could AC couple on the input side of the Sunsynk just fine - however the issue then is that as soon as the grid goes down there is no 50Hz reference available to the Fronius AC inverter so it stops its production.

With Victron there is the infamous 1:1 rule about how this works and also a certain amount of battery required. I have never heard of anything like this mentioned for the Sunsynk so presume this cant be done on the sunsynk range of inverters. However, what do I know? hence asking here.

[Scorp007]

3 hours ago, Delta9 said:

Hi guys,

Wondering if the Sunsynk Inverters can be AC coupled to the inverter OUTPUT - the same as the Victron inverters can be AC coupled to the output of the Victron's using a Fronius AC inverter? (even has the Fronius inverters in the victron menu system)

I think one could AC couple on the input side of the Sunsynk just fine - however the issue then is that as soon as the grid goes down there is no 50Hz reference available to the Fronius AC inverter so it stops its production.

With Victron there is the infamous 1:1 rule about how this works and also a certain amount of battery required. I have never heard of anything like this mentioned for the Sunsynk so presume this cant be done on the sunsynk range of inverters. However, what do I know? hence asking here.

A few days ago I read a post where someone figured out how to use a Solis with Victron instead of the Fronius. I think a lot of people with pure grid tied would like to know if and how it can be done. Major condition will be to isolate the grid input as to not export.

Perhaps a lot easier just to move loads from non essential to essential on the Sunsynk during a power failure?

[Delta9]

11 minutes ago, Scorp007 said:

Perhaps a lot easier just to move loads from non essential to essential on the Sunsynk during a power failure?

In my particular application I want to run water pumps - as many as I can manage as i have an endless need for water. So its all dependant on how many panels I can get up. AC coupled is the most efficient - until the grid goes down and that is more frequent then we would like (remote area). So the Victron system with Fronius works well for this and is a known thing - and those big Quattro's can certainly handle the load (3ph setup). However there are lots of extras one needs with Victron and this adds up fast. 

Sunsynk look to be an economical answer - if they can do the job. HF transformer  Vs Victrons Toroidal transformer, Victron has Fronius setup in it menus etc. With Sunsynk it would appear that the S.S inverter can supply non essential loads from the main DB - but this would be DC coupled - ie, DC from Solar Panels/batteries to the non essential loads via the main DB (using the current transformer that comes with the S.S). I see lots of niggles here on the forum about the S.S not supplying loads correctly from solar so not sure if S.S can supply lots of power from a big panel setup to the non essential loads via the main DB ? Victron can do it with Fronius no issues at all but at great cost.

So wondering which way to go with the whole system. I feel like Victron is tried and true and a known "thing" and Sunsynk "may" be able to do it but its a bit of an unknown qty at this time.

Thoughts?

[Scorp007]

The interesting thing here seems to be the guys with niggles seems to be that not all the PV is used when having batteries. Those that run it as a pure grid tied without batteries are finding it uses all the PV all the time.

This does not help as it seems you need the with batteries system to supply the AC input when there is no grid unless you use the Victron to be the grid input during power failures so that the grid tied can produce AC from panels.

I am sure other members will be able to assist?

[P1000]

Why not add more sunsynks? It's priced similar to the Fronius.

[SYC]

23 hours ago, Delta9 said:

In my particular application I want to run water pumps

Suggestion: Have a look at the AUX port on sunsynk,how it works,etc might be what you looking for

[Delta9]

9 hours ago, Scorp007 said:

with batteries system to supply the AC input when there is no grid unless you use the Victron to be the grid input during power failures so that the grid tied can produce AC from panels.

thats an interesting idea - use another inverter running on battery to deliver AC to the aux port of the main sunsynk system when the grid is down.

 

If the main sunsynk is running without batteries and gets an AC feed on its AUX feed from another inverter running on batteries,  then the main sunsynk is getting a 50 Hz signal and should be able to lock to that 50 Hz signal and be able to produce energy from its connected panels - while the grid is down.

 

I am sure there are lots of reasons why this wont work........although i dont know what these reasons may be.

anyone offer some thoughts on the above scenario?

[Delta9]

5 hours ago, P1000 said:

Why not add more sunsynks? It's priced similar to the Fronius.

in what way do you mean add more sunsynks ?

[P1000]

8 minutes ago, Delta9 said:

in what way do you mean add more sunsynks ?

Instead of Sunsynk+Fronius just 2xSunsynk.

[Scorp007]

1 hour ago, Delta9 said:

in what way do you mean add more sunsynks ?

It is turning out very interesting If it can work itt gives another big plus for Sunsynk.

[GreenFields]

https://www.sunsynk.org/post/ac-coupling-must-watch

Apparently the Sunsynk can do AC Coupling, but on the Generator port, not the normal load or grid ports. Been giving it some serious thought (and would be grateful if anyone could answer whether you could add an AC-coupled auxiliary load as well as add panels via the Sunsynk's own MPPT's simultaneously). Any opinions from someone who's actually done this?

If you have a grid-tied inverter in place this seems more affordable than using some other brands, but from scratch two parallel Sunsynks seem a fair option also.

 

[Delta9]

it does indeed "seem" like a S.S can AC couple on its Aux port (gen power in port)

 

 

However its quite hard to understand what Keith is trying to say - its a muddled convoluted conversation going on in this video. If you listen hard and maybe play it a few times, it seems like he is trying to say a grid tied inverter can be connected to a sunsynk inverter that has batteries attached to it via the AUX port (gen in port) of that sunsynk inverter with batteries attached to it and that same inverter with batteries attached to it can supply power to the circuits in the DB board at the same time as the other grid tied inverter because of the CT from the Sunsnyk that has the batteries attached to it.

I wish Sunsynk would consider upping thier game and doing some professional video's - get someone who can explain it all clearly to present the concepts 

Edited April 28, 2022 by Delta9