On Grid and Off Grid Hybrid Setup
Hi all i'm a homeowner and currently working with a local installer on the design and installation of a new solar system. My preferred design would be to use a pair of Sunsunk 3.6Kw units but the installer has some concerns if we would get DNO approval or not due to the 7.2Kw output potential of the entire system.
As such I wonder if the attached design is something that is an approved design as I believe your units will work in this configuration?
Basically the 2 attached are fundamentally the same installations but in the second design the slave inverter has no grid connection and is operating in off grid mode. As such the slave inverter is able to charge the batteries and potentially provide some power via the EPS output but is isolated from the grid and physically not able to export power. Assuming the "Off Grid Battery Booster" setup is supportable design it would allow the install to go ahead with very little change and if we could get DNO approval then it is a simple alteration to grid tie the slave unit at a later date. Welcome any thoughts or feedback.
Growatt battery support is a secondary question just included in diagram as were the batteries installer suggested for his original design vs a final choice.
Also the fact that there a flat garage roof and a north roof in the diagram is a different subject which will probably be questioned by a few people but rather deal with the core question if possible in this thread.
Hi James
Great, I see.
Remember that the inverter 'system' itself uses 100W+ an hour ontop of your current GRID loads. So close to 1kW an hour and in winter thats for 12 hours. 80% DoD battery means you need a 20kW battery to cover winter night loads! PV top up battery in the day 7kW MPPT on the 3.6kW inverter will be fine.
Great Calc on the vertical panels - I looked at that myself for another installation.
As you are just installing. Have a look at this video - so mega top tips!
As an aside, personally, if you are close to power handling - I would try and fit a bigger inverter [ie apply G99 / G100] from the outset. It saves on changing EVERYTHING later.....