Hi - I'm new to this site and all things ESS! Warning - Long Post - Sorry
I want to set up a UPS for our home (in NSW Australia) using a Quattro 5kva and 48v AGM battery string (240 - 300ah - haven't decided on batteries yet). We have a 3.15kw (approx) Enphase S270 PV setup already - works great.
I believe that the basic system could be set up in parallel and the PV would cut out when grid goes down, but while the grid is up excess PV would be available to charge the batteries before export.
However, I've been told by a local installer that the system could be setup AC coupled so that during a blackout the PV would still work but exporting excess (when grid is up) would be disabled - that's fine by me.
Enphase in their documents say frequency shifting is fine but not to rely on it as they can sometimes change the parameters and therefore could cause system damage. They suggest using a Voltage Controlled Relay as well. My question is - Does anyone know how and where this device would go in the system and how it works? And in Australia is the AC coupling method suggested permitted?
Cheers and thanks for any info that can be given.