Batteries and FIT payment meter

[Battery2go]

I have a 3.6 kw solar system installed when FIT first came out. I want to have batteries installed so plan on getting new smart inverter along with 12-14 kw battery storage. I have tried bonafide battery installers, however when I say I want to island some of my power circuit in case of power cut, they say it can’t be done and still get FIT payments. I have tried looking online for wiring diagram to do this plus any extra equipment needed, without any joy. Can it be done.

 

[johnb2713]

Can you not instal a battery and an inverter AC coupled, use the EPS from the new inverter to provide your power in the event of a power failure etc, that would be my take.

 

[michael8554]

As John said, add a separate AC coupled Inverter and batteries.

The old PV inverter will still feed the FITS meter.

The installers may be saying it can't be done with only the existing inverter - true.

Or that the rewiring to island some of your house will be too difficult.

 

[johnb2713]

Or that the rewiring to island some of your house will be too difficult.

Dont bother to do the islanding, just a changeover switch on the incoming supply and away you go.

 

[michael8554]

The EPS output is probably not rated to cover the whole house load.
So "just a changeover on the incoming supply" is not the whole story.
A few crucial circuits will have to be extended to John's beefy multipole changeover switch.
With the "Normal" multipole outputs wired back to the original house CU locations.
And the "Off-Grid" multipole outputs wired to a mini CU which is fed by the EPS output.
The mini CU will require separate isolated from the grid "earthing", to protect grid workers.
The installer may only want to spend half a day on the battery install and then move onto the next lucrative install.

 

[Battery2go]

My normal usage is 0.75 kWh that’s without using the big items like kettle,oven, washing machine etc. The EPS was mainly for light circuit and Downstairs sockets for TV. During a possible power cut. i Know there are hybrid inverters that will automatically cut off power back to grid, but still allow battery power to EPS.

 

[Scruffy D]

Dont bother to do the islanding, just a changeover switch on the incoming supply and away you go.

Really? I didn't know that was possible, obviously manual and I assume cheaper than the alternatives?

 

[johnb2713]

Really? I didn't know that was possible, obviously manual and I assume cheaper than the alternatives?

Yes it's possible but as someone has kindly pointed out you must consider the earthing situation. My system has an earth rod and an auto changeover.

 

[Battery2go]

John and everyone else thanks for the advice, would someone be able to do simple diagram. I have attached a photo of my current setup with my FIT meter, preferably I would like to use a new Hybrid inverter as the current one is old and is the 3rd inverter I have had .