Second PV system?

[Stinsy]

The extra solar generation capacity will be fantastic in the darker 9 months of the year. But in the sunniest months you’ll have more power than you can use (a classy problem to have!). Eddi will definitely help out but batteries will do the heavy lifting.

[RTL2PROGRAMMER]

I am in almost exactly the same situation:
2KW solar edge system with FIT payments
want to add another PV system and have battery storage for both.

South coast renewables say that I cannot just joint the 2 PV system together after the FIT meter and then have an AC coupled battery.
They have fitted a hybrid inverter and battery on the new solar panels and an AC coupled battery that monitors the old PV system.

Early days but any power in the hybrid battery drains into the AC coupled battery!

[openspaceman]

Early days but any power in the hybrid battery drains into the AC coupled battery!

This is because the AC inverter just looks like a normal household load to the hybrid inverter, I wondered if something could be done with current transformers and battery voltage sensing but the logic defeats me. The Hybrid will charge the AC battery but not vice versa, if the AC battery is full and the FIT system in excess of house loads it must be exported unless the hybrid inverter is switched to charge from mains.

If you have cheap off peak electricity and an export tariff that is higher it is less of a worry as you can simply charge both batteries to 100% on off peak and then export excess solar generated power from either system.

[nowty]

I think Tinbum has a circuit diagram for wiring up two current transformers so they effectively work as master / slave units. If he does not read this and post I will search for the diagram, its on here somewhere.

EDIT - Found it,

[openspaceman]

It looks interesting, is there an explanation of the logic?