I'm doing some back of the envelope figures for an off the grid system, based on the government announcement that instead of the old 50% rebate for these systems to a recs multiplier - 5 x up to a 20kw system.

So for example (and remember figures are pretty rough!) and I'm using the same figures for the batteries etc, just altering the panel array size.

Say a 2.1 kw system (12 x 175 panels)

total system cost say $47500

roughly translated to:

panels $9000

batteries $25000

mmpt reg $1500

invertor $7000

installation $5000

230 recs, lets say $9200.

total cost $38300.

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say a 4.2 kw system (24 x 175 panels)

total system cost say $56500

roughly translated to:

panels $18000

batteries $25000

mmpt reg $1500

invertor $7000

installation $5000

460 recs, lets say $18400.

total cost $38300.

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say a 8.4 kw system (48 x 175 panels)

total system cost say $74500

roughly translated to:

panels $36000

batteries $25000

mmpt reg $1500

invertor $7000

installation $5000

920 recs, lets say $36800.

total cost $37700.

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ok - crazy scenario

say a 20 kw system (114 x 175 panels)

total system cost say $124000

roughly translated to:

panels $85500

batteries $25000

mmpt reg $1500

invertor $7000

installation $5000

2190 recs, lets say $87600.

total cost $36400.

Can you see where this is going or am i missing something, apart from an increase in the installation and regulator costs as the system increases in size, and whether a 10-20kw array can actually fit into this battery setup - or is it apparent to go as big as possible for no extra cost?