Single or 3 phase

[Alan Ambrose]

>>> This isn't about using more electricity, its about being able to time-shift higher loads into an off-peak window,

 

So, using less electricity overall but potentially higher peak loads? And using cheap electricity when it’s available? A lot of Germany’s domestic supply is 3P and the Germans invented the PH principles. But beware of just adding up the peak loads and assuming you will want them all pulling peak at the same time. It’s a functional and statistical thing, but it’ll never happen. For instance, unusually for the UK, I have a flat that has 3P at 67A per phase, so 200A. The building doesn’t have great insulation and my power usage is about 11,000 kWh pa. That’s an average of 5.5A against a fuse rating of 200A. I would guess my peak is never more than 25A and I have electrical resistance heating, that is, it’s all instantaneous load.

 

As I said go for it if you want. You can also install 3P but use only single phase. You can also use single phase for the majority of the house, but 3P for some appliances. Bear in mind that tariffs will change over time. For instance, I think it’s possible that excess PV production on the grid during the sunny summer months may make daytime electricity super cheap in the middle of the summer day.

 

I think you then just need to guide your installer so the whole thing probably isn’t 3P. The big decision is whether you have 3P PV inverters. That gives you a potential higher export possibility but at the cost of higher plant & install costs, less choice and more complexity. It also means you need a more intelligent or experienced sparky - very few have 3P experience.

 

[IanR]

3 hours ago, JohnMo said:

Even if you did charge both cars every night and you did a 1000 miles in each car, every month, the charge time each night (for each car) would be 0.8hrs using an 11kW charger assuming the car is doing around 3.5kWh per mile.

 

I've not come across 11kW single phase charging. Are there chargers that offer in the UK?

 

Using a Tesla Model X as an example, just because it has 22kW charging capability and a 100kWh battery. It's 15 hours to charge from 0% - 100% @ 7kW and 6 hours @ 22kW

 

 

100kWh battery size is recognised in the industry as the base size that family cars need to get to be considered equivalent to ICE cars for range. Cost and battery technology are stopping this from being the case at the moment, but battery technology is changing relatively quickly. We're 5-10 years away from 100kWh batteries starting to become the norm for family sized cars.

 

For the medium size van owner, that keeps their van on the drive, expects to carry 1 tonne in the back and occasionally tow a couple of tonne, their battery size will need to be +200kWh. The next generation of medium van EVs will be coming out before 2030 with up to 150kWh batteries followed up post-2030 with +200kWh batteries.

If you are putting a new power connection in now, and it doesn't cost that much more for 3 phase, it's worth protecting for 22kW and multiple 7kW charging.

[JohnMo]

6 minutes ago, IanR said:

 

I've not come across 11kW single phase charging. Are there chargers that offer in the UK?

 

Using a Tesla Model X as an example, just because it has 22kW charging capability and a 100kWh battery. It's 15 hours to charge from 0% - 100% @ 7kW and 6 hours @ 22kW

 

 

100kWh battery size is recognised in the industry as the base size that family cars need to get to be considered equivalent to ICE cars for range. Cost and battery technology are stopping this from being the case at the moment, but battery technology is changing relatively quickly. We're 5-10 years away from 100kWh batteries starting to become the norm for family sized cars.

 

For the medium size van owner, that keeps their van on the drive, expects to carry 1 tonne in the back and occasionally tow a couple of tonne, their battery size will need to be +200kWh. The next generation of medium van EVs will be coming out before 2030 with up to 150kWh batteries followed up post-2030 with +200kWh batteries.

If you are putting a new power connection in now, and it doesn't cost that much more for 3 phase, it's worth protecting for 22kW and multiple 7kW charging.

Think you have missed my point.

 

If you are charging every day you are not fully charging the battery every time. It's little and often.

 

If everyone has 200kWh batteries bang goes the time of use tariffs as well, because peak time becomes night time - premium rate, so we don't get grid collapse. 

[Mr Blobby]

9 minutes ago, JohnMo said:

If everyone has 200kWh batteries bang goes the time of use tariffs as well,

 

Time of use tariffs will always be available. 

Here in Ireland (NI is part or the Irish market, not GB) demand falls off a cliff at night and wind generation is curtailed.  Regardless of how many EVs are on the road there will always be a need for an incentive to shift load into the E7 hours.

 

29 minutes ago, JohnMo said:

 

If you are charging every day you are not fully charging the battery every time. It's little and often.

 

Little and often is ok if you don't do many miles.  If I were to commute to Dublin three days a week then I would need to charge my 75 kW battery at 11 kW every night and that would only just fit inside the E7 window.  (thankfully I don't do this any more, but I did in the past)

 

2 hours ago, Alan Ambrose said:

The big decision is whether you have 3P PV inverters. That gives you a potential higher export possibility but at the cost of higher plant & install costs, less choice and more complexity.

 

The problem I found is that here in the UK the PV suppliers have no clue and don't want to sell 3P hybrid inverters.  When I approached UK inverter suppliers they just wanted to flog me three single phase inverters, which is fiendishly complex and crazy expensive.  There are plenty of good 3P G98 compliant inverters, its just that UK suppliers don't stock them and don't want to sell them, probably beacause there is too little demand here to make it worthwhile.

Look overseas however and it is a different story.  We are getting our 3P inverter from an EU supplier where there is lots of choice at good prices.

 

[Mr Blobby]

11 hours ago, mjc55 said:

Is it still a requirement to have meter in an external cabinet?  They wont be coming to take a reading and it makes more sense to install the meter in the plant room!

 

It depends on your DNO.  Here in Northern Ireland NIE are probably the least flexible.  Temporary cabinets must be brick built and cannot be made perananet and meter cabinets must be in a permali box on the wall.  I did try to reason with them but they were having none of it. 

 

Can you not make your temporary box permanent?  That would have been my first choice if the DNO allowed it. 

There are no smart meters here and so the meter reader needs access to the meter, hence it is so restrictive.  I assume it is more progressive in England so you will have more choice of where the meter goes.

[IanR]

4 hours ago, JohnMo said:

Think you have missed my point.

 

If you are charging every day you are not fully charging the battery every time. It's little and often.

 

Not at all, I'm not agreeing that averaging out a monthly mileage to a little and often daily charging is how EV owners wish or expect to use their vehicles. Range anxiety is unfortunately not showing any signs of subsiding and the average EV driver wants their vehicle at +80% charge at the start of any journey, so expects to be able to charge to that level overnight, no matter how depleted their battery is.

 

4 hours ago, JohnMo said:

If everyone has 200kWh batteries bang goes the time of use tariffs as well, because peak time becomes night time - premium rate, so we don't get grid collapse. 

 

I didn't claim "everyone" will have a 200kWh battery. But with ~100kWh batteries becoming the norm restricting a home to a 7Kw charger would mean you have little choice of when to charge as you'll need it charging the whole time it's on the driveway.

 

Again,

5 hours ago, IanR said:

If you are putting a new power connection in now, and it doesn't cost that much more for 3 phase, it's worth protecting for 22kW and multiple 7kW charging.

[LnP]

6 hours ago, Mr Blobby said:

  We are getting our 3P inverter from an EU supplier where there is lots of choice at good prices.

 

@Mr Blobby would you mind sharing what kit you've gone for, prices and where you got it?

Thanks

[Mr Blobby]

4 hours ago, LnP said:

@Mr Blobby would you mind sharing what kit you've gone for, prices and where you got it?

Thanks

 

Panels are on our roof but we haven't purchased the inverter yet.

 

Theses are the panels we have on the roof.   

https://leisurepower.co.uk/solar/solar-panels/rigid/15139/10-x-aiko-455w-all-black-solar-panels-aik-a-mah54-455-ab-g2?gad_source=1&gclid=CjwKCAjwodC2BhAHEiwAE67hJIC4gQq28yAfvy0rndgda032mOLPHGcf0UW0m6trniTA3LBsW8jIqRoCGsUQAvD_BwE

 

... we purchased the panels from an installer who put them on the roof for us.  We're very pleased with his work so far.

We used S5 pvkit clamps onto standing seam.  The UK suppliers only sold the old version so we ordered the new version 2.0 clamps direct from the US.

 

Our installer can't source our chosen inverter within the UK but he is happy that we supply it and he installs it.

 

This 3-phase hybrid inverter has been available on the continent for over a year but the last time I looked all the UK suppliers were selling the old series 5 model.  Which is no good for us because we want the latest model with >2 MPPTs. 

https://etronixcenter.com/en/8176291-se307-solis-solis-s6-10kw-hybrid-inverter-compatible-with-pylontech-force-h2-hv-battery-including-logging-stick-wifi.html

 

Yes its fully G98 compliant... https://connect-direct.energynetworks.org/device-databases/search-gen?model_number=S6-EH3P10K-H-EU

 

We will be plugging in a pylontech H2 battery. Probably this one.... https://etronixcenter.com/en/8173159-pyl-h2-1421-pylontech-pylontech-force-h2-hv-system-1421kwh-1x-fc0500m-40s-v2-4x-fh9637.html

 

... and conected to this will be a couple of zappis.  And maybe an Eddi.

 

Edited September 1 by Mr Blobby

[kandgmitchell]

On 03/08/2024 at 14:22, mjc55 said:

So how many on here have gone for 3 phase on their newbuild?

 

I haven't looked into this yet and so have no real insight as to the necessity to go for 3 phase so this may be a silly question.

 

I have a quote for a single phase connection to site and was wondering if this was increased to 3 phase, would the costs vary significantly.

So going back to the OP's query - I paid £300 extra for three phase which goes to external cabinet. 3 phase cable to house but currently on single phase only but the extra is there if needed.

[mjc55]

8 minutes ago, kandgmitchell said:

So going back to the OP's query - I paid £300 extra for three phase which goes to external cabinet. 3 phase cable to house but currently on single phase only but the extra is there if needed.

 

I meant to update the thread.

 

The quote came back and was around £600 more than  the single phase quote (£7.7k as opposed to £7.1k).

 

Of that about £200 or so was to with 1/3 phase and the rest just look like general cost increases since last December.