The bog-standard home wallbox doesn’t do that, but there are models with load management available
I wonder how this would be implemented since usually the place where the car is charged (the drive or a garage) is nowhere near where the main cable goes into the house and into the consumer unit. So you need a current transformer, and either a long wire to be installed or some wireless connection.
More recent units are capable of being controlled by the power network to manage overall demand; I think this was made mandatory in the UK a couple of years ago, don’t know about the UK.
Maybe a typo there but how is that implemented? Data sent over the power line, same way as remote meter reading? Might be a problem for DIY installed chargers… there is a “conspiracy” (actually I hate that word – it gets used for every kind of commercial interest) between electrician’s trade associations and the govt.
The power connection will always operate on 230V 3 Phase, but at massive currents compared to the typical DC charger. These days 50kW are common, 150kW less so and 300kW are rare
Wow – 300kW at 230V means basically the whole street-end transformer just for you 
The cable is around 600mm² and about 5cm diameter
A few years ago I went to an EV conference and one presenter made the point that if more than ~3 people in an average street buy a Tesla, and fit the max-capability charger (which then was ~50kW, which btw needs 3 phase anyway) then the street-end transformer will be at full capacity. I presume this has somehow been addressed, but it must involve load measurement for that transformer, and data sent to the chargers in that street. I can’t imagine somebody doing the other obvious option which is taking the transformer size, say 300kW, and dividing by the # of houses, say 50, and setting the ceiling in any electrician-installed charger to 300/50, which would be ridiculously low.
Peter wrote:
3 people in an average street buy a Tesla, and fit the max-capability charger (which then was ~50kW, which btw needs 3 phase anyway)
There’s absolutely no need to have 50kW at home. 1/10 or less is enough. The “standard” is 7.4 kW or 11, but 2-3kW is enough for everyday use. It’s also best for the batteries. Better to invest in stuff like load balancing and so on using 7.4 kW max output only when electricity prices are low.
And nobody can afford these – an 50kW AC charger costs 10k pounds/euros or so.
It is also completely pointless. A typical single phase 32A / 7kW installation can charge even the largest 100kW batteries from 20 to 90 percent in ten hours, which translates to 200 miles or so range. A continental 3×16A three phase charger gives 11 kW and does the same in less than 7 hours.
If you drive up to 100 miles per day, you can recharge in a 4-hour “low cost” window at 7 or 9p per kWh.
Come home in the evening, plug in, leave full in the morning.
AC chargers with 50kW or more are really to top up on longer trips.
Peter wrote:
Maybe a typo there but how is that implemented? Data sent over the power line, same way as remote meter reading?
Yes.
Might be a problem for DIY installed chargers… there is a “conspiracy” (actually I hate that word – it gets used for every kind of commercial interest) between electrician’s trade associations and the govt.
In Luxembourg, I just learned, it is simply forbidden to charge one’s car (at more than 7kW triphased or some lower limit I forgot monophased) if not through a charger box that will obey these data signals to “back off”, and which has been declared beforehand (so that the amount and capacity of installed chargers can be taken into account into the planning of network upgrades).
Hmmm. Here in the UK they cannot stop you installing anything electrical in your house, DIY. Only if you sell the house could a surveyor cause trouble.
Peter wrote:
Maybe some EVs can plug-in to a 3 phase AC socket i.e. no charger?
My understanding is that yes, they can. The cable may not be included in the price of the car, but you buy it and it works.
Peter wrote:
I dont know how (or whether) a charger measures the house draw and scales down its output limit based on that; obviously it is possible, but do they? AFAIK they don’t; the installer makes the above calculation and adjusts the charger’s ceiling.
In Luxembourg we have “smart counters”; they enable not only remote near-real-time measure of power consumption, but also that kind of communication. Frankly I don’t know if they communicate with the car wallbox charger on a “hous load level”, but they do communicate both with the network and with the wallbox charger so that if the network sends a message “reduce load now”, they send a message onwards to the car wallbox charger “reduce load now”. A car wallbox charger that doesn’t obey these messages is (if its capacity of beyond a certain threshold) simply not legal to connect and/or use.
Peter wrote:
Hmmm. Here in the UK they cannot stop you installing anything electrical in your house, DIY.
I didn’t push them as far as “show me the law and/or regulation”. But they definitely say “it is forbidden”.
An EV cannot connect to a simple 3 phase connector (or a simple 1-phase wall plug) because the “glorification” is missing. At a minimum the wall box or the “granny charger” coming with the car needs to be able to tell the car how much current it can deliver. Not a complicated or expensive thing but without it (via the data lines in the connector) the car won’t charge.
I am pretty sure there are EVs which can plug into a 13A UK socket… little ones?
I did not bother to get wallboxes for our EVs and for 11 years now have been using the 2.5 kW chargers that came with the cars. 220V single-phase. It’s because I charge them with solar but also need power for the house (9kW peak power generated). Funnily, the instruction booklet of one of the cars says “for occasional use only”.
