Fully electric with solar

LHB · Mar 22, 2023 3:17 pm

Hi All,

We are having a new fully electric home built, with the plan to install solar and a solar battery, this is all so new to us, having never built a new home or been fully electric. Can anyone out there tell me if we will run into problems with having only single phase power (we are building in a small country town in Victoria and don't know if the power will be 40amps or 63amps.)
Our builder has said we should be fine, but I don't find this reassuring. I don't know if we should be requesting to upgrade our power to 2 phase or 3 phase if it is available.
I have heard a few stories from people with fully electric homes that they overload the power which blows the power when they have the heater, oven, cooktop and a few other appliances running. Where they then have to switch off appliance so that the meter box is not overloaded.
Our appliances are electric hot water with heat pump, induction cooktop, double electric wall oven, ducted heating and cooling- 17kw system.

I am also not sure if having solar or running the appliances off solar and battery makes any difference to the amps that are available from the meter box and the grid. I understand the electricity usage that solar will generate but not enough about the total power demand required by the house.

Can anyone shed some light on what we should lookout for or advise on the power phase we should have installed.

thanks, Lynne

ponzutwo · Mar 22, 2023 3:48 pm

Im no sparky or profesionl in this space by any means, but always go three phase if you can. If you ever want to build a workshotp, do welding, have all your appliances on etc you will end up coming up against some problems.

at the very least if you get an EV it wont take you forever to charge the thing using single phase

There's also a maximum of 5kw per phase feed in to the grid. So if you go single phase and have a large enough system, your pay off wont be nearly as quick via the Feed in Tarif.

LHB · Mar 22, 2023 3:52 pm

ponzutwo

Im no sparky or profesionl in this space by any means, but always go three phase if you can. If you ever want to build a workshotp, do welding, have all your appliances on etc you will end up coming up against some problems.

at the very least if you get an EV it wont take you forever to charge the thing using single phase

There's also a maximum of 5kw per phase feed in to the grid. So if you go single phase and have a large enough system, your pay off wont be nearly as quick via the Feed in Tarif.

Hi ponzutwo,

thanks for your response, I get what you are saying, better to be save than sorry.

cheers, Lynne

strannik · Mar 22, 2023 3:56 pm

what he said.

apart from solar feed in limitation, there are also limits on how much you can consume through single phase. and while most domestic houses probably will never reach that limit, it's something to be mindful of if you're planning for lots of power hungry things, like traditional/instant electrical water heaters, large aircons, pool pumps etc.

the upgrade to 3 phase isn't that much, i think it was under $1000 for us. also allowed us to put 13.3kW solar system in

sifntdaz · Mar 22, 2023 3:57 pm

go 3 phase. don't get a battery until you live in the house and determine if you will even have much to store after your required use.

I have an all electric house with a 12KW system and it is not economical for me to get a battery.

LHB · Mar 22, 2023 4:08 pm

sifntdaz

go 3 phase. don't get a battery until you live in the house and determine if you will even have much to store after your required use.

I have an all electric house with a 12KW system and it is not economical for me to get a battery.

thanks sifntdaz, appreciate your feedback, will take it on board, our current home has solar but no battery and we find that we are hardly using any solar during the day (feeding the grid for peanuts) and then drawing all this power at night.

cheers Lynne

stonesthrow · Mar 24, 2023 10:56 am

If you don't have a long run for the power from the street to your house then I would go 3 phase as the upgrade shouldn't be more than $1-2k. The two benefits are: potentially charge an EV 3 times faster than on single phase (quick top up charge) and it allows you to run any machinery/welders that require 3 phase.

It's not the end of the world if you don't though. You will be fine regarding usage (unless you want to build a workshop with 3 phase machinery. An EV could still charge at 7kW with a 32 amp circuit. That means it could charge an empty battery to full overnight. As for solar PV feed in restrictions, it's likely that all states will adopt flexible exports (as SA is currently doing) meaning you could export up to 10kW on a single phase. So I wouldn't worry about the feed in restrictions as they currently stand.

LHB · Mar 24, 2023 4:16 pm

Hi Stonesthrow, thanks for your reply, appreciate the advice, regards Lynne

Pulse · Mar 24, 2023 8:22 pm

agree with stonesthrow, get 3 phase, it gives you more options and allows a spread of loads across 3 phases especially with a large aircon

LHB · Mar 25, 2023 9:57 am

thanks Pulse, we have now asked our builder to install 3 phase if it is available.

josh&eve · Apr 23, 2023 2:17 am

In addition to the reasons mentioned above, for anybody else that stumbles across this in future I thought I would add that many induction cooktops require 3 phase power in order to provide the 'boost' functionality of the cooktop and / or run multiple cooking zones. I built an all electric 3 phase house and Henley wired the bosch induction cooktop to 2 phases whilst isolating the rest of the house onto it's own phase. If you have a lot of air conditions, in addition to induction cooking plus all your standard household loads it can pull quite a bit.

Finally, one other aspect I haven't seen mentioned is that 3 phase power delivery tends to be more stable. So depending on the number of houses on your street you won't see as much voltage fluctuations when compared to a single phase.

stonesthrow · Apr 23, 2023 9:02 am

josh&eve

In addition to the reasons mentioned above, for anybody else that stumbles across this in future I thought I would add that many induction cooktops require 3 phase power in order to provide the 'boost' functionality of the cooktop and / or run multiple cooking zones. I built an all electric 3 phase house and Henley wired the bosch induction cooktop to 2 phases whilst isolating the rest of the house onto it's own phase. If you have a lot of air conditions, in addition to induction cooking plus all your standard household loads it can pull quite a bit.

Finally, one other aspect I haven't seen mentioned is that 3 phase power delivery tends to be more stable. So depending on the number of houses on your street you won't see as much voltage fluctuations when compared to a single phase.

There was an article in the financial review about this on Friday. The guy was arguing against this theory suggesting its very rare that a household will ever be pulling enough load to warrant 3 phase. Especially newer houses with efficient appliances.

LHB · Apr 24, 2023 10:26 am

stonesthrow

josh&eve

In addition to the reasons mentioned above, for anybody else that stumbles across this in future I thought I would add that many induction cooktops require 3 phase power in order to provide the 'boost' functionality of the cooktop and / or run multiple cooking zones. I built an all electric 3 phase house and Henley wired the bosch induction cooktop to 2 phases whilst isolating the rest of the house onto it's own phase. If you have a lot of air conditions, in addition to induction cooking plus all your standard household loads it can pull quite a bit.

Finally, one other aspect I haven't seen mentioned is that 3 phase power delivery tends to be more stable. So depending on the number of houses on your street you won't see as much voltage fluctuations when compared to a single phase.

There was an article in the financial review about this on Friday. The guy was arguing against this theory suggesting its very rare that a household will ever be pulling enough load to warrant 3 phase. Especially newer houses with efficient appliances.

Hi Josh & Eve, thanks for the info, we have decided to play it safe and have 3 phase installed if it is available, would rather be safe than sorry. cheers, Lynne