Solar options for home in 2022

Forums › Home Workshop DIY › Solar options for home in 2022 - 2026

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#3480358 13-Apr-2026 10:43

snowfly:

Looking for advise on my solar design below.
Have started to engage some companies for quotes (waiting for quote adjustments for larger inverters), but interested to hear others thoughts on the proposed design, if this will or won't work, or any other better suggestions.

.....

Sounds like a good set-up. FWIW I would go for the DC feed from the shed back to the house as on a three phase property I think that an additional (single phase) AC input would complicate things. Another consideration though is where you would site an EVSE ('EV charger').

The spread of panels should provide continuity of generation through the day.

Note that the Sigenergy system gives you the option of adding/including a 25DC EVSE which can operate in a bidirectional way thereby allowing V2G/V2H functionality so minimising the cost of large battery installation.

Include a HWC diverter on at least the larger HWC. You will appreciate its functionality on partly cloudy days.

https://www.harmlesssolutions.co.nz/

timmmay

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#3480364 13-Apr-2026 11:02

I wonder if multiple inverters could be an option for future shed expansion, to reduce transmission losses, and reduce the size of the inverter. I have no idea if that's possible, but it might be worth asking a professional.

tweake

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#3480369 13-Apr-2026 11:14

snowfly:

DC cable trenched back to Inverter in house (approx 35m from shed to inverter location in house garage) - using the 4th MPPT on inverter
Currently the shed is only on single phase, with a sub board, connected back to the house main board.
Is having solar on the shed in the future possible, with a large enough DC cable running back to inverter in house (any issue with voltage drop?).

Otherwise if that won't work, other options I have read about is potentially install a slave inverter in shed with its own panels, and feed AC back to the master house inverter.

if your going to do trenching etc, i would pull up the cable that goes to the shed and replace it with three phase cable. this will enable far better ev charging capability (multiple ev's, bigger ev's, faster charging) which is where you can save a lot of $$$ improving payback period.

also if you do dc back to the house, look at high voltage systems, that way you can use smaller cables.

PolicyGuy

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#3480377 13-Apr-2026 11:35

tweake:

if your going to do trenching etc, i would pull up the cable that goes to the shed and replace it with three phase cable. this will enable far better ev charging capability (multiple ev's, bigger ev's, faster charging) which is where you can save a lot of $$$ improving payback period.

also if you do dc back to the house, look at high voltage systems, that way you can use smaller cables.

And if you're doing trenching (either yourself or contractor), definitely include a duct with / for an Ethernet connection (fibre or UTP) between house & shed if you don't already have one.

fastbike

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#3480378 13-Apr-2026 11:40

tweake:

also if you do dc back to the house, look at high voltage systems, that way you can use smaller cables.

14 panels at 40Voc will be around 560V so you would need to ensure that fits within the MPPT allowed voltage of the inverter. Installer can do voltage drop calcs using some thing like jCaclc, hopefully you can use 4mm^2 cable.

https://www.jcalc.net/voltage-drop-calculator-as3008

I agree with the upgrade of the shed to 3 phase if possible, especially if you are charging cars there. I decided to go for a 3 phase charger when I bought my single phase Leaf, but now have a different car (Nissan Ariya) which will charge at 22kW - no changes required to my installation. I think many cars will support 3 phase charging in the future.

Otautahi Christchurch

fastbike

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#3480379 13-Apr-2026 11:41

timmmay:

I wonder if multiple inverters could be an option for future shed expansion, to reduce transmission losses, and reduce the size of the inverter. I have no idea if that's possible, but it might be worth asking a professional.

My 3 phase Solis can chain up to 6 inverters - they all need to be the same model though. It uses an RS485 twisted pair.

Otautahi Christchurch

snowfly

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#3480380 13-Apr-2026 11:51

Thanks for all the replies so far, appreciated.

Just to clarify, the house has an internal access double garage, which is where our daily driver parks, and where the solar installers proposed for the inverter.
So this is where we would park an EV in the future.

Currently the shed is used as a workshop, second vehicle, sports gear, storage, etc. And future plans to build a sleepout in 1/4 of the shed floor space.

Sounds like putting 3P out to the shed at the same time when running DC back to house inverter sounds like a good idea.
Data cabling would be ideal too.

fastbike

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#3480382 13-Apr-2026 12:00

snowfly:
Data cabling would be ideal too.

Use a 32mm conduit with a draw string/wire so that you are future proofed. I foolishly used the smallest conduit (20mm) when we built - the Cat 5 fitted buy when we got fibre the conduit was repurposed so we could add the UFB to avoid digging up the drive. Ended up using the existing Cat5 to draw a new Cat6 and UFB through. There's no way to add anything more now.

Otautahi Christchurch

snowfly

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#3480389 13-Apr-2026 12:05

Also forgot to mention I already have Shelly's switching contactors on the 3 x HWC elements, and use Home Assistant, so can either automate the HWC via HA, or control the Shelly's directly from Sigenergy (from what the first installer told me).

We've also had a Shelly 3EM running the last 6 months, so have a good idea on the loads per phase, what everything draws (at peak), and the house is reasonably well balanced across the phases.

tweake

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#3480402 13-Apr-2026 12:45

one other thing, you would have to ask sparky/installers about this, is factor in batteries for later on. make sure any underground cables are suitable sized if you say put the batteries on the garage. that would keep the house tidier.

tweake

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#3480403 13-Apr-2026 12:49

fastbike:

I agree with the upgrade of the shed to 3 phase if possible, especially if you are charging cars there. I decided to go for a 3 phase charger when I bought my single phase Leaf, but now have a different car (Nissan Ariya) which will charge at 22kW - no changes required to my installation. I think many cars will support 3 phase charging in the future.

with cars coming out with 500kw, 1000kw and now one has demonstrated 1200kw charging, 22kw would be considered trickle charging.

fastbike

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#3480409 13-Apr-2026 13:10

tweake:

fastbike:

I agree with the upgrade of the shed to 3 phase if possible, especially if you are charging cars there. I decided to go for a 3 phase charger when I bought my single phase Leaf, but now have a different car (Nissan Ariya) which will charge at 22kW - no changes required to my installation. I think many cars will support 3 phase charging in the future.

with cars coming out with 500kw, 1000kw and now one has demonstrated 1200kw charging, 22kw would be considered trickle charging.

Home charging LoL

Good luck getting 500kW out of your grid connection

Otautahi Christchurch

HarmLessSolutions

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#3480415 13-Apr-2026 13:16

tweake:

with cars coming out with 500kw, 1000kw and now one has demonstrated 1200kw charging, 22kw would be considered trickle charging.

To keep things in perspective 22 kW would still easily provide a full recharge overnight on any battery currently available, unless you're planning on home charging your Windrose.

https://www.harmlesssolutions.co.nz/

tweake

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#3480419 13-Apr-2026 13:29

fastbike:

Home charging LoL

Good luck getting 500kW out of your grid connection

but quite possible to get it out of the home battery storage. i know there is people out there who would use it if they had it.

richms

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#3480420 13-Apr-2026 13:32

25 is the biggest DC charger for home that I have seen offered, and that was part of a storage battery. Good improvement on the 11kw that most cars top out at, with that only being on 3 phase so 7 for most peoples max.

Richard rich.ms

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