Growatt SPF 5000 off grid inverter with grid tie micro inverters

[dcawkwell]

Hello,
I have a Growatt off grid inverter running my off grid house. It is limited to 5000watts. It seems to run the house nicely
and charge the batteries so all is good. I currently have it at it the maximum kilowatts of panels so no expansion possible there.
I was thinking rather than add a second off grid inverter it would be easier to add extra solar panels with micro grid tie inverters
there by taking the load off the Growatt during the day when the sun up. It would also allow a variety of solar panels to be used.
Would this work?

 

[sunshine_eggo]

Hello,
I have a Growatt off grid inverter running my off grid house. It is limited to 5000watts. It seems to run the house nicely
and charge the batteries so all is good. I currently have it at it the maximum kilowatts of panels so no expansion possible there.
I was thinking rather than add a second off grid inverter it would be easier to add extra solar panels with micro grid tie inverters
there by taking the load off the Growatt during the day when the sun up. It would also allow a variety of solar panels to be used.
Would this work?

Can the Growatt "AC Couple" with other inverters?
Can it frequency shift?

If the answer to either is "no" it will not work.

Grid tie (GT) inverters do not self-regulate. They are designed to output maximum power to an infinite sink (the grid). The AC coupled inverter must be able to shift the frequency away from 50/60Hz something a little higher/lower to get the GT inverter to disconnect and stop sending power.

I would investigate if your unit is parallel-able with like units. That would be the most sensible and likely most cost effective option.

 

[timselectric]

Can the Growatt "AC Couple" with other inverters?
Can it frequency shift?

That would be no, and no.

 

[timselectric]

Hello,
I have a Growatt off grid inverter running my off grid house. It is limited to 5000watts. It seems to run the house nicely
and charge the batteries so all is good. I currently have it at it the maximum kilowatts of panels so no expansion possible there.
I was thinking rather than add a second off grid inverter it would be easier to add extra solar panels with micro grid tie inverters
there by taking the load off the Growatt during the day when the sun up. It would also allow a variety of solar panels to be used.
Would this work?

And also no.

 

[timselectric]

I would investigate if your unit is parallel-able with like units. That would be the most sensible and likely most cost effective option.

It is, up to 6 units.
And the only option I would recommend.

 

[DIYrich]

You could probably add micros up to the base power of your house that it consumes 24/7. After that, you run the risk of producing too much power. Also, the micros will need to be able to sync to the inverter. Lots of threads about problems with running micros of brand X with inverter of Brand A.

Also, for the cost of a few micros, you are up to the cost of another growatt. Having two inverters gives you redundancy if one goes down.