Solar options for home in 2022

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#3448396 31-Dec-2025 11:08

insane:

Thanks @Fastbike for those that is indeed very helpful. And @Jase2985 thanks for all those shared files, wasn't expecting that so really appreciate the help!

I guess I'll need to budget for a larger system :)

Panels are cheap, and its so much easier to put them in at one time as opposed to going back to do it again later. the cost for a larger inverter is also not that much more. I do appreciate people can and are on budgets but once the payback period has been and gone, its all free power, and power aint going to be getting any cheaper.

tweake

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#3448402 31-Dec-2025 11:38

Jase2985:

Why? Because you are charging a battery from a battery, It's not very efficient, HV DC or AC > LV DC in the battery, then VL DC to AC for the EVSV (EV Charger) then back to HV DC in the EV battery. My EV is about 88% efficient from the AC charger

You are better off going straight from solar or using night rate power for this.

When charging at home you don't generally need a fast charger, as your car is sitting there during the day (WFH) or overnight while you sleep, 7kw AC charger will give you about 40km per hour of charging so for me with night rate power I can get about 400km of range overnight, not that my EV needs that much. Not many people need that amount of charging each and every day.
If you have 3phase power you can go up to 22Kw for your charging speed, but most cars dont take that much.

"fast chargers running off a home battery will become a thing." for most people in the short to mid-term I doubt it, most people just don't drive that much to need fast charging at home. as above, 40km per hour of charging is about what the average person does daily.

"the house can easily run off the mains if you deplete the battery." you don't want the house to run off the mains, that's the purpose of the battery. Most will go onto a cheaper night rate plan where they can top up their battery and also charge their car in the 8–10 hours when it's cheaper. You then use the battery to cover the peak periods that the solar can't cover, and then rinse and repeat.

i think this is a good discussion to be had.

i think its going to change. for eg the recent cars with 500kw-1000kw charging. that opens up super fast charging on suitably equipped public charging, but those owners will want similar at home. the ability to get home with a near flat battery and recharge it to 80% quicker than you can get ready for a night out. thats a huge convenience factor and also peace of mind.

that also works on a lesser scale. the ability to have fast charging at home, if you want. by making it easier and more convenient than a ice car, its a win.

i got laid off from work a while back and went from refuelling the ute at work to having to use gas stations again and manage fuel. what a pain in the rear (not to mention cost). that convenience factor of an instant refill at home/work is not to be underestimated.

i looked at getting an ev but the cheaper ones didn't have quite enough range and you had to recharge at night, or i would not get to work the next day. the bigger battery models had the range but still reliant on recharging over night due to slow speed charging. if i missed a recharge it would be a case of going to a public charger. having the ability to fast charge at home, at whatever rate you want, removes a whole lot of "what if's" with fuel management.

btw thats only with one ev. multiple ev's compound the issue.

imho getting around the bottle neck of house and garage electrical connections is worth the drop in efficiency, especially if you have lots of cheap power from solar.

fastbike

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#3448403 31-Dec-2025 11:48

tweake:

i think this is a good discussion to be had.

If you want to see the lengths some people go to, then watch Dala getting setup for 400kW home charging !
https://www.youtube.com/watch?v=HovFY44p0Fs

Otautahi Christchurch

Jase2985

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#3448406 31-Dec-2025 11:53

tweake:

i think this is a good discussion to be had.

i think its going to change. for eg the recent cars with 500kw-1000kw charging. that opens up super fast charging on suitably equipped public charging, but those owners will want similar at home. the ability to get home with a near flat battery and recharge it to 80% quicker than you can get ready for a night out. thats a huge convenience factor and also peace of mind.

They really dont, because you are not in a hurry to charge when charging at home, and you keep missing the fact that the amount the average person drives is low (40-50km per day) there is not usually a need to do a large top-up at home most days.

tweake:

imho getting around the bottle neck of house and garage electrical connections is worth the drop in efficiency, especially if you have lots of cheap power from solar.

In 99% of cases, there is no bottleneck.

your comments show thats its all based on opinion, without actually taking to people who have EV's and how they use them.

This conversation doesn't belong in the solar thread.

tweake

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#3448417 31-Dec-2025 13:31

Jase2985:

They really dont, because you are not in a hurry to charge when charging at home, and you keep missing the fact that the amount the average person drives is low (40-50km per day) there is not usually a need to do a large top-up at home most days.

In 99% of cases, there is no bottleneck.

your comments show thats its all based on opinion, without actually taking to people who have EV's and how they use them.

This conversation doesn't belong in the solar thread.

i disagree on that. solar afaik is still the cheapest way to generate home power, for home or ev. with battery cost decreasing and performance increasing, home batteries will become more common. so its becoming more of a package deal. we will see more and more use home solar to charge ev's. as people are not home to charge ev's direct from solar, you need to store it first. hence the discussion.

imho your looking at this inverted (eg survivor bias). its not the usage existing ev owners have that you need to look at, but rather what everyone else wants. telling mass market buyers they have to change their life to suit a new car is met with scorn. mass market buyers expect the next car to be better than their last. but tell them they can have an ev that does the same range as petrol car and you can charge it as quick as a gas station vist, and you can also do it more conveniently at home with no need to go to a gas station/public charger and the iceing on the cake is that your own solar power is cheaper. thats a win.

HarmLessSolutions

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#3448419 31-Dec-2025 13:48

tweake:

someone mentioned there is a fast charger with built in battery.

most kiwis homes are bottled necked by the connection to the street, fast chargers running off a home battery will become a thing.

What you're referring to is possibly the Sigenergy set-up. This has the option of a 25 kW DC charger supplied direct from its battery. The added advantage is that because it is connecting to the EV battery via a DC link it is able to reverse that current and so provide V2H, and because this is happening on the DC side of the inverter no regulatory compliance is needed beyond that already in place for the DC-AC inverter as the source of the power is no different from if the inverter was being supplied from the solar.

Our installer has already provided systems that are operating in a V2H capacity here in Taranaki but any installer with the technical skills to understand how the Sigenergy systems work is able to do the same.

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

Jase2985

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#3448446 31-Dec-2025 15:09

tweake:

Jase2985:

They really dont, because you are not in a hurry to charge when charging at home, and you keep missing the fact that the amount the average person drives is low (40-50km per day) there is not usually a need to do a large top-up at home most days.

In 99% of cases, there is no bottleneck.

your comments show thats its all based on opinion, without actually taking to people who have EV's and how they use them.

This conversation doesn't belong in the solar thread.

i disagree on that. solar afaik is still the cheapest way to generate home power, for home or ev. with battery cost decreasing and performance increasing, home batteries will become more common. so its becoming more of a package deal. we will see more and more use home solar to charge ev's. as people are not home to charge ev's direct from solar, you need to store it first. hence the discussion.

imho your looking at this inverted (eg survivor bias). its not the usage existing ev owners have that you need to look at, but rather what everyone else wants. telling mass market buyers they have to change their life to suit a new car is met with scorn. mass market buyers expect the next car to be better than their last. but tell them they can have an ev that does the same range as petrol car and you can charge it as quick as a gas station vist, and you can also do it more conveniently at home with no need to go to a gas station/public charger and the iceing on the cake is that your own solar power is cheaper. thats a win.

Again you have completely missed the point, most people don't drive that far to NEED it to charge superfast at home as it sits there for many hours while you sleep where it can charge slowly, as pointed out on a single phase charger you can put 70kw into the battery in the cheap power period (10 hours) overnight, and it's also better for the battery to charge it slower. You need it to charge fast when you are out and about, as you don't want to be waiting longer than you need to on a road trip.

Please, this is not the thread for this.

tweake

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#3448479 31-Dec-2025 16:51

HarmLessSolutions:

What you're referring to is possibly the Sigenergy set-up. This has the option of a 25 kW DC charger supplied direct from its battery. The added advantage is that because it is connecting to the EV battery via a DC link it is able to reverse that current and so provide V2H, and because this is happening on the DC side of the inverter no regulatory compliance is needed beyond that already in place for the DC-AC inverter as the source of the power is no different from if the inverter was being supplied from the solar.

Our installer has already provided systems that are operating in a V2H capacity here in Taranaki but any installer with the technical skills to understand how the Sigenergy systems work is able to do the same.

more power please 😁 not sure on the specs, but one of the new twin gun ev's with a couple of those units. charge house battery up with off peak to say 50%, then use the rest of the battery for solar. so the house and car runs mostly off a mix of solar and offpeak.

tweake

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#3448487 31-Dec-2025 17:20

Jase2985:

Again you have completely missed the point, most people don't drive that far to NEED it to charge superfast at home as it sits there for many hours while you sleep where it can charge slowly, as pointed out on a single phase charger you can put 70kw into the battery in the cheap power period (10 hours) overnight, and it's also better for the battery to charge it slower. You need it to charge fast when you are out and about, as you don't want to be waiting longer than you need to on a road trip.

Please, this is not the thread for this.

are you seriously telling people what they do or not need? why are you against something that would boost ev adoption and solar installs?

why pay for the most expensive power at a public charger when you can have the cheapest power at home. but people want to charge up when they want to and to their requirements, not some average. this is the point here, all the tech exists, tho some of it is still bleeding edge. i think the fastest decent sized battery takes about 5 min to charge to 80%.

also the big problem here is you NEED 10 hours to slow charge. what happens when your late home, or want to go out for the night or the charger doesn't work one night.

people want fast charging with their own cheap power. which ties this all into home solar and battery systems.

kangaroo13

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#3448488 31-Dec-2025 17:23

solar afaik is still the cheapest way to generate home power, for home or ev.

...most people don't drive that far to NEED it to charge superfast at home as it sits there for many hours while you sleep where it can charge slowly, as pointed out on a single phase charger you can put 70kw into the battery in the cheap power period (10 hours) overnight, and it's also better for the battery to charge it slower. You need it to charge fast when you are out and about, as you don't want to be waiting longer than you need to on a road trip.

As someone with solar, considering both EV and battery down the track, I mostly agree there is no need to fast charge the vast majority of the time, and it is kinder on home battery to charge directly into the car (save cycling the home battery), and kinder on the car battery to charge at slower speeds. It is also kinder on wallet and environment to just trickle in any excess solar that may be available. The EvNex charger (7.4kW, single phase) seems quite a good option in this regard. That's probably where I'm headed. My motivation for solar is not only financial, but environmental, and charging off the grid overnight doesn't tick the green box as much as charging off solar.

Nevertheless, it would be nice to have the option to charge a bit faster than 7kW sometimes - perhaps recharging before a longer journey that wasn't anticipated, or a quick top-up just before departing. SigEnergy do a 25kW DC-DC charger, but it is quite expensive for the relative few times I think it would be used in my case. I think a 'proper' fast charge of 100kW+ at home would be quite unnecessary. I don't think people moving to an EV should expect to use it just like an ICE with a "petrol station" at home.

kangaroo13

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#3448490 31-Dec-2025 17:32

tweake:

also the big problem here is you NEED 10 hours to slow charge.

You're assuming a situation where you get home with battery fully depleted, and you need to drive a long distance the very next day ... that's not typicaly usage. Most people would travel 30-40km per day, and just need a top-up each day, for which a slow charger (7kW => ~1hr) would fit the bill most of the time.

I really don't think a home super-fast recharging (e.g. 5min per your example) is something that most people would need to invest in, and it wouldn't be kind on either home or vehicle battery.

Jase2985

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#3448491 31-Dec-2025 17:49

tweake:

are you seriously telling people what they do or not need? why are you against something that would boost ev adoption and solar installs?

Im telling you based on current experience on forums, multiple EV pages on Facebook and Reddit that at home charging off a 7kw charger is more than enough for 99% of people most of the time. Yes there are sometimes you may need more, but your payback on the device just isn't there which is what most people look at.

tweake:

why pay for the most expensive power at a public charger when you can have the cheapest power at home. but people want to charge up when they want to and to their requirements, not some average. this is the point here, all the tech exists, tho some of it is still bleeding edge. i think the fastest decent sized battery takes about 5 min to charge to 80%.

also the big problem here is you NEED 10 hours to slow charge. what happens when your late home, or want to go out for the night or the charger doesn't work one night.

People want fast charging with their own cheap power. which ties this all into home solar and battery systems.

Unless you are road tripping, you seldom need to use a fast charger I've used one twice in 2 years both on road trips, and you can't use your home charger anyway, unless you are a taxi or courier or something, and then you fall into that 1%.

You don't NEED 10 hours to slow charge, you have 10 hours you CAN slow charge on cheap power. or you charge during the day off solar.

You keep IGNORING the fact that the average journey of a New Zealander is less than 40km per day. that's 1h or charging to top it back up. You don't need a 25kw charger to do that.

Where are these people you speak of?

At the end of the day, charging your EV from your home battery doesn't make sense, a small home battery topping up a large car battery.

HarmLessSolutions

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#3448492 31-Dec-2025 17:50

kangaroo13:

Nevertheless, it would be nice to have the option to charge a bit faster than 7kW sometimes - perhaps recharging before a longer journey that wasn't anticipated, or a quick top-up just before departing. SigEnergy do a 25kW DC-DC charger, but it is quite expensive for the relative few times I think it would be used in my case. I think a 'proper' fast charge of 100kW+ at home would be quite unnecessary. I don't think people moving to an EV should expect to use it just like an ICE with a "petrol station" at home.

The other restriction on fast charging in a home situation is that most domestic connections top out at 63 amps so ~15 kW is the maximum you can draw down your home's incoming main. Even with 3 phase you're not going to even come close to 100 kW. That also puts the Sigenergy's 25 kW DC charging ability into perspective.

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

prob

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#3448573 1-Jan-2026 09:17

What you're referring to is possibly the Sigenergy set-up. This has the option of a 25 kW DC charger supplied direct from its battery. The added advantage is that because it is connecting to the EV battery via a DC link it is able to reverse that current and so provide V2H, and because this is happening on the DC side of the inverter no regulatory compliance is needed beyond that already in place for the DC-AC inverter as the source of the power is no different from if the inverter was being supplied from the solar.

Our installer has already provided systems that are operating in a V2H capacity here in Taranaki but any installer with the technical skills to understand how the Sigenergy systems work is able to do the same.

So is this only available with a Sigenergy system with batteries or can you solely use the car batteries for VTH?

Intrigued as I didn't think ant VTH solutions are available in NZ.

Tell me more.

HarmLessSolutions

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#3448581 1-Jan-2026 10:23

prob:

What you're referring to is possibly the Sigenergy set-up. This has the option of a 25 kW DC charger supplied direct from its battery. The added advantage is that because it is connecting to the EV battery via a DC link it is able to reverse that current and so provide V2H, and because this is happening on the DC side of the inverter no regulatory compliance is needed beyond that already in place for the DC-AC inverter as the source of the power is no different from if the inverter was being supplied from the solar.

Our installer has already provided systems that are operating in a V2H capacity here in Taranaki but any installer with the technical skills to understand how the Sigenergy systems work is able to do the same.

So is this only available with a Sigenergy system with batteries or can you solely use the car batteries for VTH?

Intrigued as I didn't think ant VTH solutions are available in NZ.

Tell me more.

The key feature of the Sigenergy system is that the EV charger is on the DC side of the inverter which is where the input from the solar (and batteries) usually are. The EV battery then becomes just another potential DC input which is then converted to AC by the inverter.

Using this configuration to convert the EV battery DC to grid AC does away with the need for a bidirectional EVSE which faces the grid and therefore needs certification as a grid connected device. With the Sigenergy system there is no direct connection of the EV battery to the grid as the inverter sits between EV and grid.

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

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