here is a scaleable microgrid isolation device that fundamentally is a directional contactor to install at the service entrance. the idea is to have some battery and be able to defeat utility curtailment of your solar production, yet you can suck as much grid power as you want.
from the specs, it is not clear if this fronius will synthesize grid to cause the other grid tie inverter to work when the grid is down. It may do so, and you want it to do so, so you get all solar output when the grid is down. the schneiders do synthesize grid. there is a fronius gen24 6kW version, larger than the one you identified, with two mppt inputs. you could sell your enphase microinverters to pay for the larger fronius. you could sell your 250w panels and upgrade to more 450 watt units and then make money selling power to your utility. (do they pay?)
Don't know about mounting the panels on the pergola colourbond roof sheets though? Anyone done this?
Could even have a go at mounting them myself maybe.
from the specs, it is not clear if this fronius will synthesize grid to cause the other grid tie inverter to work when the grid is down.
Ok, this is getting nuts. I'm being inundated with solar/battery companies.
Enphase want to help out with system expansion and storage, whatever I need.
Fronius actually got back to me today and are keen for the hybrid inverter or whatever.
I just got sent an EcoFlow 3.6kWh DeltaPro battery and portable solar panels.
And Holymils just emailed about a collab for microinverters and storage or whatever.
WTF do I do?
I envy your issues, that companies want to send free stuff for the advertisement. Stuff that practically makes money.
Did you already check/consider Victron Multiplus II as hybrid/off-grid inverter (which is intended for 12/24/48V batteries, enablig low-cost DIY battery storage)
OK, so back of the napkin calculation for Tesla powerwall:
System costs 10K, Dave said it's OK for 10 years.
10 years *365 days * 10 kwh = 36500 kWh usable capacity. At 0.30AUD/kWh the system barely pays for itself (10950 AUD), by cycling it 100% DoD, every single day.
If you would include the feedback rate, probably it would be 15 years or more to pay for itself?
10 years *365 days * 10 kwh = 36500 kWh usable capacity.
For option 1: why not get a single inverter (with multiple strings)? That saves half the cost (using a 10kW 3 phase inverter) compared to the Enphase AND you get more power output because from what I've read from the specs, the Enphase inverters can't deal with the full output of the solar panels. The solar panels I have on my roof are rated for 4500Wp total but I've seen them produce up to 5kW. I'm also not convinced by the IQ8 relays; I have a customer who had two of those relays burn out. The more stuff you add, the more that can break.
Prices for the panels also seem high. Over here a 400+ Wp panels costs less than 80 euro each.
Over here a setup with 27 panels + inverter would cost around 3200 euro (materials) with a maximum power delivery to the grid of 10kW.
For option 1: why not get a single inverter (with multiple strings)? That saves half the cost (using a 10kW 3 phase inverter) compared to the Enphase AND you get more power output because from what I've read from the specs, the Enphase inverters can't deal with the full output of the solar panels. The solar panels I have on my roof are rated for 4500Wp total but I've seen them produce up to 5kW. I'm also not convinced by the IQ8 relays; I have a customer who had two of those relays burn out. The more stuff you add, the more that can break.