Context: I have just moved in to a house in Metro Melbourne 2 months ago. The house has underfloor slab heating which eats up a lot of electricity - we experimented with it a little bit and think during winter 80kw/day usage is on the higher end (and that’s only turning on the main zone!). I would like some guidance / opinions on the system size, inverter options and ballpark costs. Note that I have a 3 phase system.
- Option 1: 10.73kW system, with 29x panels North and West facing, 1x 10kW inverter
- Option 2: 13.32kW system, using 36x panels North, West, East facing, 2x 5kW inverters (due to 3 panel direction)
- Option 3: 16.65kW system, using 45x(!) panels North, West, East facing, 1x 5kW and 1x 10kW inverter
Question on options:
a) What would be the ballpark price difference between each options?
b) Does it make any financial sense to do option 3 as I assume the costs would be quite high?
To make a more informed decision, I’m trying to get comparable quotes across retailers by asking them to use similar products. It is hard though to ask them to give me prices for the 3 options above and with different products for the different options!
Solar panels - I’ve asked them to use the CER recommended ones, the ones put forward were Trina / Jinko / Canadian Solar / REC.
Solar inverters (remembering I have a 3 phase) - I’ve been given 3 options:
- Fronius Symo
- Sungrow SG5KTL-D
- Solaredge SE10K with the optimisers
My questions on the inverters are:
a) Is the Fronius much better than the Sungrow for the 3 phase models? How much more expensive are they as a ballpark? It seems hard to justify going with the Fronius with 5 year warranty (with additional 5 years for parts) compared to Sungrow’s 10 years.
b) I assume that the SolarEdge is a more expensive option. I don’t have shading so am thinking either the Fronius or Sungrow should do the job well?
c) Are there any other inverters I should consider for 3 phase?
d) Is it worth considering adding a battery in the future when prices are cheaper seeing that I don’t generate enough solar for winter with the underfloor heating? Will batteries be compatible with all 3 of these inverters / is there anything I need to consider?
Thank you in advance!