Solar options for home in 2022

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#3479238 8-Apr-2026 14:53

LightbulbNeil:

That looks to be a sizeable house.

I would suggest a 15kw system with a 10kw 3phase inverter.

...

Yes - but with gas hot water and space heating, no EV (yet), and presumably no need to run the pool pump ;-), I'm not sure he needs a 10kW inverter. Obviously he would need to consider current and projected power usage.

Agree that a bit of clipping is no big deal. I think it is more important to size the system to try to get reasonable power through the winter months at the cost of a bit of clipping over the middle of the day in summer. This will likely become more the case if/when feed in tarrifs drop in NZ, as they have in Australia.

Jase2985

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#3479239 8-Apr-2026 14:58

kangaroo13:

Jase2985:

Example is my system, where i couldn't put the panels anywhere else, ...

6.6kw facing 297 degrees and 3.3kw facing 117 degrees, you can see the WNW ones generate way more than 50% more power than the ESE ones. In peak summer it gets closer to the 50% more but if there are better options i would go with them.

What I find most interesting there is that your WNW string starts earlier than your ESE string, and they track reasonably closely over the morning. With more panels, the WNW string has potential to exceed the inverter string switch-on voltage earlier, nevertheless, it will get direct sun much later in the day. Was the light a bit diffuse that day (light clouds?)? Perhaps it is a low roof pitch also?

It doesn't, that day just had a slight bit of cloud in the morning, as it was a quick, recent example I found. The roof pitch is 30 degrees.

On a perfect summers day (Jan 11th) the ESE starts anything meaningful about 0730 and peaks about 1140. The WNW string starts generating more power by about 1045, with its peak being about 1500 before dying off about 2000

Jase2985

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#3479241 8-Apr-2026 15:01

LightbulbNeil:

I would suggest a 15kw system with a 10kw 3phase inverter. If you have an electric car, that will make a difference in the summer for charging, and the extra pannels will be useful in winter.

Why 3 phase? Presumably they only have single phase as thats the inverter they were quoted

LightbulbNeil

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Master Geek
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#3479245 8-Apr-2026 15:22

Jase2985:

LightbulbNeil:

I would suggest a 15kw system with a 10kw 3phase inverter. If you have an electric car, that will make a difference in the summer for charging, and the extra pannels will be useful in winter.

Why 3 phase? Presumably they only have single phase as thats the inverter they were quoted

I suggested 3phase as they appear to be looking at electric car charging. 3phase based charging is cuurently used for fast er chargers compared to single phase 15 amp chargers. Fast chargers are around 60 amps or so, so the majority of the current that is supplied to a single phase house supply. They could go single phase too, but 3phase allows for a more balanced approach. It also depends on the number of phases to the house currently. In theory the house could be run through the inverter and the battery, then be 3phase while the house only has a single phase supply, and a single phase export.

I went 3 phase as we have 3phase to the house, and I have wood work machines that have 3kw 3phase motors.

johno1234

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#3479246 8-Apr-2026 15:22

Look at this bloody great Camphor Laurel shading our roof! Could probably fit 10 panels each on the garage north pitch and at the west end of the house.

That tree is beautiful to look at but it drops deadwood on the roof which would be extra annoying if it was smashing the PV panels.

tweake

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#3479253 8-Apr-2026 15:33

LightbulbNeil:

I suggested 3phase as they appear to be looking at electric car charging. 3phase based charging is cuurently used for fast er chargers compared to single phase 15 amp chargers. Fast chargers are around 60 amps or so, so the majority of the current that is supplied to a single phase house supply. They could go single phase too, but 3phase allows for a more balanced approach. It also depends on the number of phases to the house currently. In theory the house could be run through the inverter and the battery, then be 3phase while the house only has a single phase supply, and a single phase export.

I went 3 phase as we have 3phase to the house, and I have wood work machines that have 3kw 3phase motors.

not a silly idea. but an extra inverter adds to the cost.

single phase for the house, a 3ph inverter to run the faster charger and other products you might want. with a lot of new ev's starting to come out with big batteries and hyper charging.

dukezoid

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#3479256 8-Apr-2026 15:49

dantheperson:

timmmay:

@maoriboy I agree the price seems high. I'd probably get a cheaper but reputable panel brand, and add more panels.

Is Canadian Solar an expensive panel brand? That's what tradedepot sell in their packages, e.g. $20K installed for 18 panel canadian solar, 8Kw inverter deye, 14kWh battery DAH solar

https://tradedepot.co.nz/18-panel-home-solar-system-8kw-inverter-14kwh-battery-installation_908719/

I assumed it was the SigEnergy inverter pushing up the price. If you are not getting batteries i don't know that i'd spend extra on a fancy inverter, there's nothing for it's software smarts to do.

Probably your layout with multiple faces would cost a bit extra though.

Agree with others, get those panels onto the more north facing roof faces.

e.g. these spots. you might get a bit of shading, e.g. morning shade on the yellow one, but that's far less shading than you'll get on the large SW face.

PS. the pool needs a clean.

I’d not go any less than an Sigenstor 8.0 Single Phase EC, you need at least 3 MPPTs to cover your varying preferred aspects. Price differential at wholesale is small (see below $AUD), if you’re being quoted more than $750 to step up between models try elsewhere. The 12.0 is AU$3,500 incl. Here in NZ more like $3,800 incl @ cost

The 10.0 and 12.0 have 4 MPPTs. Charging your EV at 32A plus HWC plus misc you’ll appreciate having a 10 or 12 - works fab for most of us.

If going for larger string (6kW+) be aware that Sig has max of 16A per string - I’ve seen clipping on peak summer days from a 13 x 500w panel string.

Three phase would seem overkill unless you’re also looking to run a pool. Also have to budget $10 - $15K to run the two additional phases, upgrade meter, upgrade wiring to MCB etc

Jase2985

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#3479258 8-Apr-2026 15:50

LightbulbNeil:

Jase2985:

LightbulbNeil:

I would suggest a 15kw system with a 10kw 3phase inverter. If you have an electric car, that will make a difference in the summer for charging, and the extra pannels will be useful in winter.

Why 3 phase? Presumably they only have single phase as thats the inverter they were quoted

I suggested 3phase as they appear to be looking at electric car charging. 3phase based charging is cuurently used for fast er chargers compared to single phase 15 amp chargers. Fast chargers are around 60 amps or so, so the majority of the current that is supplied to a single phase house supply. They could go single phase too, but 3phase allows for a more balanced approach. It also depends on the number of phases to the house currently. In theory the house could be run through the inverter and the battery, then be 3phase while the house only has a single phase supply, and a single phase export.

I went 3 phase as we have 3phase to the house, and I have wood work machines that have 3kw 3phase motors.

Unless they already have a 3 phase supply there is no point as its normally a huge expense to upgrade.

As single phase charger will give you about 40km per hour of charge, so in most cases its plenty.

richms

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#3479259 8-Apr-2026 15:50

tweake:

not a silly idea. but an extra inverter adds to the cost.

single phase for the house, a 3ph inverter to run the faster charger and other products you might want. with a lot of new ev's starting to come out with big batteries and hyper charging.

Not seen any inverters that will drive a 3 phase load when only fed with single phase grid tho. That would be useful for people wanting motors and stuff who dont want to deal with a VFD and rewiring them to be 230v delta.

Biggest that happens over the type 2 appears to be selected cars that do 22kW, anything else will be DC fast charge, even if only at 25kW from the home battery, so 3 phase will not help.

I was looking at a 3 phase upgrade when I had flatmates and was hitting the limits on a 63A supply, but it didnt stack up. Would really not work out for just me even tho it would be nice to be able to use industrial surplus things like compressors and thicknessers.

Richard rich.ms

Jase2985

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#3479260 8-Apr-2026 15:52

johno1234:

Look at this bloody great Camphor Laurel shading our roof! Could probably fit 10 panels each on the garage north pitch and at the west end of the house.

That tree is beautiful to look at but it drops deadwood on the roof which would be extra annoying if it was smashing the PV panels.

Unfortunately your place is one of the smaller % of places that just really isn't suited to solar. Too much shade from that tree.

maoriboy

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#3479271 8-Apr-2026 16:15

kangaroo13:

LightbulbNeil:

That looks to be a sizeable house.

I would suggest a 15kw system with a 10kw 3phase inverter.

Yes - but with gas hot water and space heating, no EV (yet), and presumably no need to run the pool pump ;-), I'm not sure he needs a 10kW inverter. Obviously he would need to consider current and projected power usage.

Agree that a bit of clipping is no big deal. I think it is more important to size the system to try to get reasonable power through the winter months at the cost of a bit of clipping over the middle of the day in summer. This will likely become more the case if/when feed in tarrifs drop in NZ, as they have in Australia.

5 adults live here - one retired so basically home all day. Average summer combined electricity/gas bill is around $400 a month, winter can almost double that. Not sure if adding 3 phase is worth the added expense. We've had an ev for about 4 years now and managed to keep it nicely topped up using the granny charger. Just wanting to add a dedicated charger for future vehicle needs.

Enough about the pool 😂. The pic was obviously captured at a moment in time when we were away for an extended period of time....or something equally plausible 😎

johno1234

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#3479305 8-Apr-2026 18:13

Jase2985:

johno1234:

Look at this bloody great Camphor Laurel shading our roof! Could probably fit 10 panels each on the garage north pitch and at the west end of the house.

That tree is beautiful to look at but it drops deadwood on the roof which would be extra annoying if it was smashing the PV panels.

Unfortunately your place is one of the smaller % of places that just really isn't suited to solar. Too much shade from that tree.

I agree. Bit of a shame but if I ever attempted to remove that tree I’d have a crowd of neighbours outside waving and pitchforks. I couldn’t bring myself to do it anyway.
Not visible in that photo but under the canopy of the large tree there’s a line of trees between the house’s north side and the driveway which had grown up into the house’s light. So over Easter I was cutting out a few of them and feeding them into a trailer mounted chipper. I think one neighbour was horrified! Her south side and my trees so I’m not losing sleep over it.
The chipper from Hirepool was a beast! Vapourised trees into mulch without even blinking.

timmmay

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#3479339 8-Apr-2026 19:31

Having shade from the north means less air conditioning is required, so there's that. We have to air condition north facing bedrooms from about Nov to March.

johno1234

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#3479355 8-Apr-2026 21:04

timmmay:

Having shade from the north means less air conditioning is required, so there's that. We have to air condition north facing bedrooms from about Nov to March.

The 1960s architecture is quite good. There’s a full length veranda so the high summer sun doesn’t shine directly in but the low winter sun does. We only seem to run the heat pump in the depth of winter.

fastbike

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#3479361 8-Apr-2026 22:34

richms:

tweake:

not a silly idea. but an extra inverter adds to the cost.

single phase for the house, a 3ph inverter to run the faster charger and other products you might want. with a lot of new ev's starting to come out with big batteries and hyper charging.

Not seen any inverters that will drive a 3 phase load when only fed with single phase grid tho. That would be useful for people wanting motors and stuff who dont want to deal with a VFD and rewiring them to be 230v delta.

Biggest that happens over the type 2 appears to be selected cars that do 22kW, anything else will be DC fast charge, even if only at 25kW from the home battery, so 3 phase will not help.

I was looking at a 3 phase upgrade when I had flatmates and was hitting the limits on a 63A supply, but it didnt stack up. Would really not work out for just me even tho it would be nice to be able to use industrial surplus things like compressors and thicknessers.

We have 3 phase, it's a bit of a mixed blessing. Double oven is split across two phases, likewise HWC with lower (hardly used) and upper elements. Heatpump 4kW is single phase as 3 phase was not available at the time. Everything else is "balanced" across the phases.
We had a Nissan Leaf - single phase 6kw charger - so would be exporting from battery and sending 2/3 to grid if we weren't careful.

So at times you can end up with importing at peak rates and exporting at half that rate if you are not careful.

Anyway re EV, we now have an Ariya with 3 phase charging so that problem is gone.

Workshop has 3 phase machines, biggest is 5kW saw. So that could be supplied by VFD if I was starting over.

Although having 63A x 230v x 3 = 43kW is an interesting proposition. Can I afford that sort of power bill ?

Otautahi Christchurch

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