I have a potential client who runs a business from his house and I' trying to find a solution for his property.

During the day, he has high loads(over 30kW), but at night it's a normal household. The area has lots of power outages

Is it possible to AC-couple grid tied inverter like a 50kW Solis with a 12kW Sunsynk?

The idea is to ensure that

1. The daytime loads are taken care of.

2. He has backup power for the house at night and

3. Critically, the grid-tied Solis keeps running even in the event of loadshedding or some other outage

 

An obvious solution would be hybrid inverter like an Atess, but that very quickly blows the budget.
 

Why do you post the same topic twice?

It's definitely possible.  But if you need to ask for advise here, perhaps you may want to pass on this install.  It isn't going to be a typical install and it'll definitely require reading manuals/datasheets to see what the inverters support and figuring out a way to accomplish it.  This will be compounded if you are going to use a single battery for both inverters.

Also I would weigh up the complexity of two inverters against paralleling how every many Sunsynk inverters are required and then turning a bunch off at night (again something that needs research to confirm is possible, how, etc.)

Edited January 29, 20223 yr by Gnome

On 2022/01/28 at 12:39 PM, Leratse Energy said:

I have a potential client who runs a business from his house and I' trying to find a solution for his property.

During the day, he has high loads(over 30kW), but at night it's a normal household. The area has lots of power outages

Is it possible to AC-couple grid tied inverter like a 50kW Solis with a 12kW Sunsynk?

The idea is to ensure that

1. The daytime loads are taken care of.

2. He has backup power for the house at night and

3. Critically, the grid-tied Solis keeps running even in the event of loadshedding or some other outage

 

An obvious solution would be hybrid inverter like an Atess, but that very quickly blows the budget.
 

Just keep in mind that the sunsynk can not charge from the AC inverter when no grid is available. It is not an Inverter/Charger but rather a bidirectional inverter, it can not invert and charge at the same time. 

Furthermore placing a 50KW ac inverter onto a 12Kw off grid inverter may lead to instability in the grid I believe this is why Victron for example requires your AC Coupled inverters to not exceeded the KVA rating of your hybrid inverter. The hybrid inverter has to regulate the grid and with a 50Kw AC inverter it may fail to do this effectively. 

Also Keith from sunsynk advises that AC Coupled inverters should be placed onto the Gen Port and not the load.... this may be a problem for you also as I would not put 50Kw through the Gen port of a 12Kw sunsynk.

Have you considered looking at an SMA system for this, they offer much more scalable systems and specialize in AC Coupled solar? 

Is it within the budget to parallel 3 sunsynks