Solar System - Multi string, shade, roof, ground....garage, house lawn...

[Dukesolar]

I have 2 friends and a son that are sparkys - son is 3yrd year. One friends has installed a lot of solar. Our Average power bill is $600+ a month. 1787kw usage for August (winter NZ). 60kw / day.

SO - I am thinking that these fellows can help me do a DIY - sort of install.

Winter Sun is worst as we live in a gully - we get the morning sun and afternoon, gone about 3pm. Roof A&B House, C is garage.


Roof A - 10 Panels - North Facing - Sun 8am - 3pm
Roof B - 10 Panels - East Facing - Sun Part shade - all day - 3pm
Roof C - 10 Panels - East Facing - Sun All Day - 3pm
Ground Mount 20 Panels - North Facing - All Day Sun

Ground Mount 20 panels - connected after sign off.... North facing all day sun. About 50m - 100M away - though thick steep bush. Power will need to be run through conduit along a fence line. Then trenched across small lawn - run under house to solar shed.


2 or 3 Phase system

• • Inverter 1: MPPT1 = Roof A (10), MPPT2 = Roof B (10)
  • Inverter 2: MPPT1 = Roof C (10), MPPT2 = Ground (10 of the 20)
  • Inverter 3: MPPT1 = Ground (other 10), MPPT2 + spare capacity

• • Roof B shading: Lose a bit of output at certain times in winter, but with a dedicated MPPT the other roofs + ground keep pumping.
  • Ground mount: Split into 2 × 10-panel strings (parallel or separate MPPTs) for flexibility.
  • Balance: Total DC ~22 kW, AC output capped at ~10 kW (export limit) → lots of headroom for winter and cloudy days, with clipping on sunny peaks (not a bad thing). CHGPT.. comments

Roof

House is 1996 - original iron roof, color steel very good condition, colour is starting to fade - NO rust - Just had it painted. Looks great.

We have 10yrs left before retirement and are not looking to move any time. Been here 20yrs... will die here most likely.

I will build a dedicated solar room under our house to keep everything dry and at ideal temp. I could even add a heat pump to keep cool or warm at extremes temps - in Hunua AKL.

Is this a suitable idea?
Panels 500W -440W

Full Hybrid + AC-Coupled System​

1. Core Hybrid System (at house solar room)​

• Inverter (main brain):
  • 1 × Deye SUN-30K-SG01HP3-AU-BM3 (30 kW 3-phase hybrid, Vector approved).
  • Wall-mounted on solid backing in solar room (under house, dry/cool).
  • Handles: grid connection, battery control, backup output, 35 roof panels.
• Batteries:
  • 8 × Micromall 409 V 5.2 kWh HV modules (≈ 41.6 kWh total).
  • Mounted in HV cabinet with integrated BMS and isolators.
  • Cabinet sits beside inverter in solar room.
  • Ventilation: keep < 30 °C, ideally 15–25 °C; your idea of adding a small heat pump/dehumidifier is excellent.
• Panels (roof arrays = 35 modules, LONGi LR5-54HTB 440 W):
  • Roof A (north): 12 panels – 1 string → MPPT1.
  • Roof B (east, shaded): 12 panels – 1 string → MPPT2.
  • Roof C (east/garage): 11 panels – 1 string → MPPT3.
  • Mounting: Crest-fixed feet on corrugated iron, stainless screws with EPDM washers + butyl pads. Rails across corrugations, mid/end clamps for 30 mm frames.
  • DC cabling: PV1-F 4–6 mm², MC4, lockable DC isolators at inverter. Inline string fuses not needed (1 string per input).
• Protection at house:
  • 1 × AC isolator at inverter.
  • Type 2 AC & DC SPDs at inverter board.
  • Dedicated sub-board for backup loads (pump, fridge, lights, comms).
  • CT clamps on mains for export-limit (most networks 10 kW cap).

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2. Ground Array (20 modules on separate inverter)​

• Panels: 20 × LONGi LR5-54HTB 440 W (≈ 8.8 kW DC).
  • Stringing: 2 × 10-panel series strings → each MPPT of a second inverter.
  • Mounting: Ground rack (galv steel or aluminium, portrait 2 × 10), anchored with posts or ground screws. North-facing, full-day sun.
• Inverter (AC-coupled):
  • Can be another Deye string inverter (e.g. Deye SUN-8K-G03, 8 kW 3-phase, Vector approved).
  • Mount on post or small cabinet at ground array.
  • Has its own CT kit for export-limit (sits on mains alongside the hybrid’s CTs).
• AC run back to house:
  • Cable: 4c + earth XLPE/SWA/PVC, 6–10 mm² Cu depending on length (100 m → 6 mm² ≈ 1.6% drop, 10 mm² ≈ 0.9%).
  • Above-ground through bush: UV-rated conduit, saddled to fence/posts. Add expansion loops, mechanical protection at crossings.
  • Last 5 m trenched in conduit, marker tape, depth per AS/NZS 3000.
  • Terminate in solar room board.
• Protection at array:
  • 1 × 3-pole AC isolator beside inverter.
  • Earth electrode bonded to frames + inverter chassis.
• Protection at house board:
  • 1 × 3-pole MCB (20–25 A) feeding the array inverter circuit.
  • Type 2 AC SPD at the board.
  • Labelling per AS/NZS 5033.

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3. Whole-Site Integration​

• Two Deye inverters:
  • Hybrid Deye 30 kW → manages roof PV, batteries, backup, grid tie.
  • String Deye 8 kW → ground PV only, AC-coupled.
  • Both export to grid via same mains.
  • Both use CTs on mains to enforce export limit.
  – Hybrid CTs control battery charging/discharging.
  – String inverter CTs cap its output when site load/export limit reached.
• Monitoring:
  • Deye portal/app can see both inverters (same brand = one platform).
  • You’ll have full visibility of roof vs ground generation, battery SoC, site load.

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Summary​

• Inverters: 2 × Deye (30 kW hybrid at house, 8 kW string at ground).
• Panels: 35 on roof (3 strings: 12 + 12 + 11), 20 on ground (2 strings: 10 + 10).
• Batteries: 41.6 kWh HV cabinet in solar room.
• Mounting: Roof → crest brackets with EPDM seals; Ground → racking with posts/ground screws.
• Cabling: Roof DC → solar room, 4–6 mm²; Ground AC → solar room, 6–10 mm² XLPE/SWA in conduit/fence trench.
• Protection: DC isolators (roof strings), AC isolators (both inverters), SPDs (DC & AC), CT clamps on mains, backup sub-board.
• Compliance: AS/NZS 3000, 5033, 5139, 4777.2; Vector-approved inverters; proper CT export limiting.

 

[WorldwideDave]

Can you break this down into short questions you might get more eyes on this. It’s great that you have some friends that can help you install this. Do not underestimate the amount of time it takes to install panels, however. That sounds like you’re basically doing three different installations. But you got this.