Adding a timer to an EV charging point.

[ProDave]

Don't worry about the high loads and duty electrician thing.  That questionnaire looks like it will cover anything from a house to a factory.  Just tell them about the 24kW boiler and how it operates e.g on a timer.

 

The CT thing would be applicable if you had solar PV and a diverter to sent power to an immersion heater (CT = current Transformer that clamps onto one of the meter tails)

[Jeremy Harris]

One of the problems if smart metering gets used for load shedding (every smart meter is capable of doing this - your supply can be remotely turned off if you have a smart meter) is that they need to sequence the way loads are brought back on line after a load shedding event.

 

At the moment, there are no published plans to use domestic load shedding, it only applies to commercial users.  However, the remote disconnection provision was included in the smart meter spec, for two reasons, to allow customers to be cut off if they fail to pay their bills (this primarily applies to those with credit meter type tariffs at the moment) and to allow load disconnection in the event of a major network problem (much the same as the LFDD system that applies to commercial users). 

 

One of the problems with load shedding by turning the supply off to customers is that when the supply is turned back on the grid may see a large step increase in load.  Managing big step changes is challenging, so, where possible, they like to be able to sequence reconnection so that users with large connected loads aren't all switched on at the same time.  This used to be a potential problem when night storage heaters were popular, and teleswitch controls were common, and its pretty common now to find that the time clock in an off-peak meter with switch control is slightly out.  Having all the meter clocks on a very different time means that the off-peak loads don't all switch on at the same instant.

 

My guess is that they want to know about any heavy loads in order to assess the impact of any reconnection event.

[newhome]

On 08/02/2020 at 15:15, Jeremy Harris said:

You can probably do a test to see how your car responds to the charge point going live after being plugged in, by turning off the circuit breaker (with the car unplugged), plugging the car in, waiting for maybe half an hour to be sure the car has fully shut down it's onboard systems, then switching  the circuit breaker on.  This is safe, as turning the power on initially won't draw a high current, as the charge point has to boot up and then do the control pilot handshake with the car, before it will turn on its internal contactor.  If the car charges OK doing this, then you have the option of adding a time switch and contactor to the circuit supplying the charge point.  This is probably the cheapest option overall.

 

I tried this last night and it appears to have charged ok so that seems like a good option although someone told me I wouldn’t find a timer for a 30A charger. I have visions of sticking a post it note up to remind me to switch the circuit breaker on and off! 

 

I’m going to do some rough stats gathering over the next few days to ascertain how many units I use in the 3 hour peak period with just the normal stuff running, eg lights, fridge freezers etc. as that will all cost more than I’m paying now. Then run some tests so that the boiler comes on to warm the slab up and provide DHW overnight, so that I can assess how much it has cooled by the following evening to see if it’s viable to change the boiler switch on timings. If the slab has cooled too much I guess I could stick the thermostat up by another 1 degree if the electric is half the price? 

 

 

[ProDave]

What you need is a normal timer switching a contactor.

 

Is there any spare space in the consumer unit that feeds the charger?  Picture?

[newhome]

3 hours ago, ProDave said:

What you need is a normal timer switching a contactor.

 

Is there any spare space in the consumer unit that feeds the charger?  Picture?

 

Here is the CU that feeds the charger (marked EV). 

 

 

[ProDave]

Ah a 3 phase board.  Not so convenient.

 

You would be looking at something like this,  https://www.ebay.co.uk/itm/CONTACTOR-63-AMP-2-POLE-AC-12kW-NORMALLY-OPEN-HEATING-LIGHTING-DIN-RAIL-MOUNT/174122632964?epid=6007308395&hash=item288a848704:g:dYcAAOSwBY5d8RnJ

 

It might be possible to put that inside the CU, but not in place of a pair of mcb's as you can often do with a single phase board.  It all depends how much room there is inside and how much depth.

 

Alternatively the contactor could be mounted above or alongside the CU in it's own enclosure.

 

Use a normal single channel central heating programmer to set the on / off times. the output of the timer feeds the coil of the contactor.

 

P.S.  Have you really got two washing machines and 2 tumble dryers?

[Ed Davies]

19 minutes ago, ProDave said:

Alternatively the contactor could be mounted above or alongside the CU in it's own enclosure.

 

Use a normal single channel central heating programmer to set the on / off times. the output of the timer feeds the coil of the contactor.

 

Would a DIN rail time switch like this be appropriate to make that neat?

[Jeremy Harris]

Just now, Ed Davies said:

 

Would a DIN rail time switch like this be appropriate to make that neat?

 

That's similar to the one I use to control my charge point.  Easy enough to wire one of those to a contactor.

[ProDave]

1 minute ago, Ed Davies said:

 

Would a DIN rail time switch like this be appropriate to make that neat?

Yes you could put that and the contactor in a box together.  I merely suggested a boiler programmer as everyone knows how to use them.

[newhome]

2 hours ago, ProDave said:

P.S.  Have you really got two washing machines and 2 tumble dryers?

 

Lol, not now as it seemed to be overkill with just me living here but there is space / plumbing / wiring for a washing machine and dryer upstairs. The 2 I use currently are in the utility room. Should have included 2 dishwashers really as if this house was fully occupied that would be useful. 

[SteamyTea]

19 hours ago, newhome said:

I’m going to do some rough stats gathering over the next few days to ascertain how many units I use in the 3 hour peak period with just the normal stuff running

Do it properly

https://www.ebay.co.uk/itm/Current-Cost-EnviR-Real-Time-Home-Energy-Monitor/153515105953?epid=1623207346&hash=item23be369ea1:g:mSsAAOSwGIJc99Hw

Add in a 10 quid RPi and a cable and you can log it all

 

[jamiehamy]

Quick update from me. 

Got a quotation back from SP Energy to provide a 3 phase supply. The gods are in my favour, when we paid for the new connection, they ran a 3 phase supply down and then ran a single supply in from just outside our boundary. We need to excavate that back to the joint + a metre and they will pull out the old single supply and run 3 phase to my meter box. They'll connect a single phase to the existing meter and then it's up to me to sort a new meter. 

 

So my plan is to get the Single phase Smart meter installed. Upgrade the supply. As and when we need to use the other phases + when 3 phase Smart meters are available, w upgrade and connect the the two phases. 

 

Cost for 3 phase supply - £900inc vat. Will get it done this year and am future proof. 

[kla456]

I realise this is an old thread, but what was discussed has probably been installed by now? Feedback would be useful? And I have some questions around the same topic.

I went down the same road as JamieHamy and installed 3-phase a couple of months ago (£1400), at the same time a 3-phase consumer unit, 3-phase smart meter from Octopus and a 22kW Myenergi charger.

I had considerable disruption because SSEN did not finish on time and the 3-phase meter was not installed on the day. Another meter fitter sent later that night (emergency) was not qualified to fit 3-phase and also disconnected the PV installation - anyway!

Same as him, I fed the existing single phase consumer unit (including the existing PV inverters and the Polar charger) from the 3-phase consumer unit.

I currently have an application pending with DNO for a 12kW PV expansion with 10kW 3-phase hybrid inverter and 10kW of batteries.

DNO has asked a question:

"I note on your G99 form that the existing 6kW of PV is installed on 1 phase and the additional 10kW will be spread over three phases. Where your generation connection involves multiple phases you will need to balance the generation output evenly across the phases."  

Not really understanding the question, I replied:

"the busbar of the new 3-phase consumer unit will balance all loads across the 3 phases. "

And they replied with this comment:

"Thomas has come back to advise to add the extra generation then it will need to be balance over three phase as it does not work on single phase."

I'm not sure what they are getting at. Are they saying that the existing 2 x 3kW SolarEdge 1-phase inverters will not live happily on the same 3-phase consumer unit as the new 10kW 3-phase hybrid inverter?

 

Also, I have the same Polar dumb charger as NewHome since 2014 and I would like to install a DIN Rail time stitch  - wifi ones are available, but are they advisable?

https://www.amazon.co.uk/Circuit-Breaker-Switch-Control-eWeLink/dp/B07Q34WYR8?th=1

Then I would have a 7kW charger and a 22kW charger., both switchable by app.

The 22kW charger and the PV expansion would not have been possible without 3 phase.