Solar options for home in 2022.

Forums › Home Workshop DIY › Solar options for home in 2022.

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174 posts

Master Geek

#3283220 17-Sep-2024 14:40

fastbike:

Apart from a slightly more complicated main distribution board (it has 3 bus bars and sets of breakers) I would highly recommend it for any new "all electric" build.

Outside of specialised workshop machinery, i don't see why a normal household would need three phase? Single phase will supply 14kW load, why would anyone need more, am i missing something?

LightbulbNeil

57 posts

Master Geek

#3283225 17-Sep-2024 15:14

With a 3 phase lathe, they have the ability to stop quickly and then go into reverse. Very handy especially when thread cutting. Just makes it so much easier. Also means that older 3phase machines that were not home hobby machines can be easily connected without needing to get a 3phase inverter etc. Milling machines and thicknessers that come with 3 phase motors and controls are then just a plug in and they work situation. There are now single to 3 phase VFD units that also work really well on motors to 15kw. My house in the workshop also has the 15amp power points for air compressors and a 3hp circular saw etc. It was just a nice to have so did it. Not many want small industrial machines and are happy with the single phase lathes and milling machines etc. The 3phase stuff does run smoother and a bit quieter as well.

Neil

MikeFly

148 posts

Master Geek

#3283226 17-Sep-2024 15:16

dantheperson:

fastbike:

Apart from a slightly more complicated main distribution board (it has 3 bus bars and sets of breakers) I would highly recommend it for any new "all electric" build.

Outside of specialised workshop machinery, i don't see why a normal household would need three phase? Single phase will supply 14kW load, why would anyone need more, am i missing something?

I guess it depends on your definition of normal.

On one of the 3 hours free plans such as Z and Contact offer you charge an EV (Tesla, MG, Polestar to name a few) at 11kW using a 3ph charger, while at the same time heating your hot water, doing a load of washing and running the dishwasher and dryer, heating the underfloor tank, and if you really want to go crazy, cook a casserole in the oven.

Admittedly this doesn't happen every night, but just being able to throw 60% back into the car for free every night makes it worthwhile.

I haven't looked into the deals for solar back to the grid as yet, but having 3 phase should give the capability to send more back if that's your thing.

Scott3

3963 posts

Uber Geek

Lifetime subscriber

#3283228 17-Sep-2024 15:35

dantheperson:

fastbike:

Apart from a slightly more complicated main distribution board (it has 3 bus bars and sets of breakers) I would highly recommend it for any new "all electric" build.

Outside of specialised workshop machinery, i don't see why a normal household would need three phase? Single phase will supply 14kW load, why would anyone need more, am i missing something?

you can also get single phase in 100A with vector (~23KW).

In terms of why go three phase (either 60A / 42kW, or 100A / 69 kW), there are really two reasons.

Run three phase stuff
- This goes beyond the obvious workshop gear:
- Large pool heat pumps
- Sauna's
- Kilns
- Swim spa's
- Larger pumps
- EV's (Most EV's in NZ max out at 7kW single phase, but many of the bigger battery ones will charge at 11kW on three phase) - For a 100kWh EV like the kia EV9 AWD, this means your charge time drops from 14 hr to 9 hr. Yes I know full charges are rare, but for the person who uses all their range in a day trip (could be as little as 200km towing a larger boat), and wants to do the same thing the next day, this is valuable. Also EV's batteries keep getting bigger if Rivian ever make good on their promise to do RHD, their biggest battery is 149 kWh..
More capacity
- A 90cm induction cooktop can use 5.5 kW alone.
- A big ducted heat pump can do ~4 kW
- A 400L hot water cylinder can do 4.8 kW.
- Many single phase EV's can do 7.2 kW (yes you can get smart chargers with CT clamps to shed this load)
- Spa's can do 3+ kW
- Oven's are typically 3.6kW
- If you are fed up with residential dryers and want a commercial one, they use 4 kW+ https://speedqueen.co.nz/wp-content/uploads/2023/02/NZ-version-LWNA62_LDE3TR_LDG3TR-Washer-Dryer-SPECS.pdf

Yes it is not all at the same time, but it is easy to get to the point where you are risking tripping a 60A, or even 100A pole fuse in a larger fully electric home (especially with multiple EV).

fastbike

212 posts

Master Geek

#3283233 17-Sep-2024 15:50

dantheperson:

Outside of specialised workshop machinery, i don't see why a normal household would need three phase? Single phase will supply 14kW load, why would anyone need more, am i missing something?

Looks like some of the reasons have been provided. In the workshop all of the big machines are three phase (saw, dust collection, planer etc). The motors are more robust and spin up smoothly, also can do some clever delta/wye switching for speed/torque control.

In the house we have a twin oven, and will be replacing the gas hob in the next 5 years with induction. HWC has two 3kW elements, heatpump has a 32A circuit.

I might add an EV at some stage so the ability to do a fast home charge (requires 3 phase) would be bonus.

And I can export up to 15kW back to the grid rather than 5kW if I expand the panels in the future.

P.S. At our first house (last century) I remember tripping the mains breaker in a 1950's house if I wanted to do much in the garage and we had something happening in the kitchen - I', thinking it probably had a 230V 32A service panel !

Otautahi Christchurch

dantheperson

174 posts

Master Geek

#3283283 17-Sep-2024 15:53

Scott3:

Yes it is not all at the same time, but it is easy to get to the point where you are risking tripping a 60A, or even 100A pole fuse in a larger fully electric home (especially with multiple EV).

Ah so 'fully electric' means mulitple EVs. Though we'd want to charge those on solar roght?

I guess my thinking on 'normal' was like typical nz household using 8kWh/year. Excluding those with kilns, commercial dryers, and Rivians towing the boat 200kms everyday :)

My heat pump dryer pulls 400w max.

SumnerBoy

2074 posts

Uber Geek

ID Verified

Lifetime subscriber

#3283286 17-Sep-2024 16:10

Yeah I recently built and was close to going with 3 phase, but in the end was talked out of it by my sparky.

We are an all-electric household, with pool, two EVs, induction hobs, electric HWC (with 2x 3kW elements), but no industrial machinery ;).

We also have 7.8kW of solar and a Tesla Powerwall, and we very rarely pull over 10kW, thanks to the PW Gateway doing a very good job of regulating when it will charge the car, battery etc.

The main reason I opted out of 3 phase was the solar + battery - I didn't want the extra expense of a 3 phase inverter, and the Powerwall is only able to backup a single phase. So it meant the PW would only "see" 1/3 of my solar generation. The alternative was to stick with a single phase inverter but then anything on the other 2 phases would have no solar offset and be pulling from the grid the whole time.

Now that Tesla have rolled out "Charge on Solar" the Powerwall Gateway is even better at ensuring we soak up as much solar as possible, by diverting any excess to the EV (only works for Tesla EVs, not the e-Golf). But it means we are exporting less and less now than ever. Something that would not be possible if the EV charger was on a different phase to the PW etc.

HarmLessSolutions

969 posts

Ultimate Geek

Subscriber

#3283288 17-Sep-2024 16:28

SumnerBoy:

Yeah I recently built and was close to going with 3 phase, but in the end was talked out of it by my sparky.

We are an all-electric household, with pool, two EVs, induction hobs, electric HWC (with 2x 3kW elements), but no industrial machinery ;).

We also have 7.8kW of solar and a Tesla Powerwall, and we very rarely pull over 10kW, thanks to the PW Gateway doing a very good job of regulating when it will charge the car, battery etc.

The main reason I opted out of 3 phase was the solar + battery - I didn't want the extra expense of a 3 phase inverter, and the Powerwall is only able to backup a single phase. So it meant the PW would only "see" 1/3 of my solar generation. The alternative was to stick with a single phase inverter but then anything on the other 2 phases would have no solar offset and be pulling from the grid the whole time.

Now that Tesla have rolled out "Charge on Solar" the Powerwall Gateway is even better at ensuring we soak up as much solar as possible, by diverting any excess to the EV (only works for Tesla EVs, not the e-Golf). But it means we are exporting less and less now than ever. Something that would not be possible if the EV charger was on a different phase to the PW etc.

We opted to go for a single phase setup when we last upgraded our solar. Evaluated our likely maximum consumption and decided to move all circuits onto one of our two phases. The extra expense and phaffing around with prioritising between phases and price of 3 phase inverters and EVSEs just wasn't worth the extra export ability we would have had available.

Nice to see Tesla have added solar diversion to their home systems' management system. Just a pity they could have allowed integration with non-Tesla EVs as is possible for Evnex EVSEs. Ring fences their customers' product choices I guess.

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

SumnerBoy

2074 posts

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Lifetime subscriber

#3283289 17-Sep-2024 16:34

HarmLessSolutions:

Nice to see Tesla have added solar diversion to their home systems' management system. Just a pity they could have allowed integration with non-Tesla EVs as is possible for Evnex EVSEs. Ring fences their customers' product choices I guess.

Yeah it is a shame, but my understanding is that the Powerwall actually talks to the vehicle to control how much it should be charging, based on the excess solar available. It obviously can't do that with non-Tesla vehicles.

Would be interested to see how the EVNEX manages this - does it just limit the amount of power being delivered to the vehicle? I was under the impression the vehicle generally decides how much to charge, up to the limit of the charger of course. Not something I know enough about clearly.

HarmLessSolutions

969 posts

Ultimate Geek

Subscriber

#3283295 17-Sep-2024 16:42

SumnerBoy:

HarmLessSolutions:

Nice to see Tesla have added solar diversion to their home systems' management system. Just a pity they could have allowed integration with non-Tesla EVs as is possible for Evnex EVSEs. Ring fences their customers' product choices I guess.

Yeah it is a shame, but my understanding is that the Powerwall actually talks to the vehicle to control how much it should be charging, based on the excess solar available. It obviously can't do that with non-Tesla vehicles.

Would be interested to see how the EVNEX manages this - does it just limit the amount of power being delivered to the vehicle? I was under the impression the vehicle generally decides how much to charge, up to the limit of the charger of course. Not something I know enough about clearly.

Evnex EVSEs monitor the outgoing main by way of a CT clamp and then transfers equivalent power into the EV, with a 1.4kW minimum/7kW maximum (or as dictated by the EV's set maximum). A relatively simple strategy and similar to that of a HWC diverter's function. Also able to be overridden by way of the phone app that controls the Evnex settings to pull maximum 7kW wholly or partially from the grid.

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

tweake

2391 posts

Uber Geek

#3283297 17-Sep-2024 16:44

dantheperson:

Outside of specialised workshop machinery, i don't see why a normal household would need three phase? Single phase will supply 14kW load, why would anyone need more, am i missing something?

single, dual, or 3 phase is dictated to by the lines company. its down to how they do the load balancing.

i can't get 3 phase here (or upgraded service) but the next town over everyone is 3 phase (which catches out sparkies as house wiring is a little different).

fastbike

212 posts

Master Geek

#3283313 17-Sep-2024 18:13

There is some interesting data that can be garnered when you get a few power meters installed. We had a 3 phase one installed last November on the incoming grid connection, and another one on the circuit for the heatpump (which only gets used in the colder winter months). The following chart shows the warm spells, and the recent cold snap.

Otautahi Christchurch

fastbike

212 posts

Master Geek

#3283318 17-Sep-2024 18:22

I was reading the alleged "advantages" of smart meters on the EA website yesterday ....

... so I fired off an email to ask how I could use this near real time to make my power use more efficient ? My email was along the lines of

"Please explain how I, as a consumer, can get near real time access to my power use data, via an API for instance that could be incorporated into a home automation setup.

I can't see anything on your website, or the websites of power companies that would enable this."

The response was, as expected, completely disappointing. Our power market lacks competition and innovation and there is nothing there to allow consumers to take back control. Instead of successive governments forcing true competition and ensuring access to information, we get crap about importing LNG (which will result in more expensive power)

Otautahi Christchurch

HarmLessSolutions

969 posts

Ultimate Geek

Subscriber

#3283322 17-Sep-2024 19:05

fastbike:

Our power market lacks competition and innovation and there is nothing there to allow consumers to take back control. Instead of successive governments forcing true competition and ensuring access to information, we get crap about importing LNG (which will result in more expensive power)

Absolutely! The idea of promoting the most expensive fuel available to enable thermal generation to further shaft our electricity pricing structure is absolutely ridiculous and would be hilarious if it wasn't so damning in terms of Kiwi's cost of living. TPTB take us for absolute numpties by even suggesting this. And to add further next breath they're o the foolishness of this scheme, the government is all to happy to recognise the issue of agricultural methane emissions while in the breath promoting our importing methane by the boatload in the form of methane. What are these clowns smoking?

For those interested in seeing how off-program our government's energy strategy is compared to internationally recognised strategies Brett Christophers' book 'The Price is Wrong' is worth checking out.

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

dantheperson

174 posts

Master Geek

#3283332 17-Sep-2024 21:13

fastbike:

... so I fired off an email to ask how I could use this near real time to make my power use more efficient ?

Yeah, that's real missed opportunity. Some jurisdictions did standardise a communication standard, so you can buy home energy monitors and the like that talk to the smart meter to get realtime data. The greens were pushing for that here when the smart meters were about to rollout, but of course our solution was that 'the market' was best placed to make any decisions about that.

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