Bit of a odd one but over the weekend a neighbour of mine offered me an obscure inverter battery system that he bought a few years back to bolster his FiT based system but never got it fitted owing to building an extension at the time (& now he's moving anyway.
It seems a little bit different to the normal coupling in that you link via PV strings - both through itself (it then converts some of this down to 48V for the battery) and sends the rest back out to the existing MPPT PV side of the existing Inverter.
When there is demand (via a CT clamp on the AC side) the system works in reverse, sending a "Pseudo" PV string voltage from the battery into the existing inverters PV Inputs.
To me this sounded like it would be a pain to make work but (assuming none of the specifications of the GE PV Input or panels side are broken) in the back of my mind it did seem a good way to get around the existing limitations of the GE battery output - Existing 2.6KW limit + PV + whatever the "Fake PV" can muster.
(With the downside being that it would only ever charge from PV as there is no AC connection at all)
I'm tempted with it as more of a plaything but the Question is - What this means for warranty? Is there a stipulation that the MPPT side must be a PV panel? (Obviously I realise it's my own fault if I set it up wrong or go over PV Voltage / Current limits on the MPPT sides)