newhome

Adding a timer to an EV charging point.

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I’ve started thinking about what I need to do to move my electricity supply away from Scottish Power. I am currently on the Economy 2000 tariff that has 2 completely separate meters; one for standard use and the other for heating only. Each meter is currently connected to its own consumer unit. Apparently I just need to ask a spark to rewire both consumer units into a single meter. An easy job I’m led to believe? 🤔 Once this is done I believe that Scottish Power will remove the second meter and then I’ll be free to swap suppliers. 

 

The tariff I’m considering is Octopus Agile (tariff changes every half an hour) and it’s important that I set as much as I can to run overnight as that’s where savings will be made. I haven’t ever run the dishwasher, washing machine or tumble dryer overnight as I’ve always been quite fire conscious but they all have inbuilt timers so I could do that if I choose to. 

 

The heating can be reset to heat my TS overnight so no problem there but my car charger has no timer setting that I can see. It appears to be on a separate RCD so I could just flip it on when I go to bed and off again in the morning but a timer would be much more convenient as I’m bound to forget! Neither the car nor the charger has anything inbuilt to control the times. If it’s plugged in and on then it’s charging. The charger is in the garage and ideally the timer would be in the house next to the CU. Is that possible? I googled and consumer unit timers appear to be a thing? 

 

 

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It's not easy to just fit a timer to a charge point, for a few reasons.  The first one is that the current being switched is pretty high (30 A in your case, could be up to 32 A) and that means using a time switch that's capable of handling that sort of current, and they aren't that common or cheap.  Another potential issue is the way that the car and charge point interact.  This varies from one EV to another, but some need the control pilot signal from the charge point to be active as soon as the lead is plugged in, so the car can adjust its onboard charger to the advertised current, before any charge timing can happen.  Other EVs will either just accept a charge point going live whilst plugged in and start charging, throw a charging error if this happens or refuse to charge (mine does the latter, it point blank refuses to charge if the charge point is run on a time switch).  In theory timed charging like this should work OK, but theory and practice are often different when it comes to the foibles of some EVs.

 

Was your charge point installed with an OLEV, or other, grant?  If it wasn't, then you may be able to get it swapped over for a smart charge point that offers scheduled, or tariff tracking, charging, (if your car will accept this).  All new charge points that are partially grant funded have to be smart, so they can all be scheduled etc.  In your case there there are two grants available, up to £500 from OLEV plus £300 from a Scottish grant initiative.

 

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.

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Isn't there some control protocol tat you previously used to control the charging of your previous car, rather than turning on and off the mains supply?

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9 minutes ago, ProDave said:

Isn't there some control protocol tat you previously used to control the charging of your previous car, rather than turning on and off the mains supply?

 

 

Yes, there is, but it's not at all easy to break into this in a commercial charge point to do this.  My charge point is home made, and includes an enable port, that allows the control pilot connection to the car to correctly signal that charge power is, or is not, available.  The standard allows for this, and cars are supposed to stick to the protocol, but not all do.

 

My charge point has three modes, selectable via a three way switch, off, on and timed.  In the timed position the charge point signals to the car that charge power is available only during the E7 off peak period.  That worked perfectly with both the Prius Plug In and the BMW i3, but is completely ignored by the Tesla Model 3, as the Model 3 doesn't seem to follow the protocol, and refuses to wake up and start charging when the charge point signals that power is available. 

 

The advantage of doing it the proper way, like this, is that the timer is only working with logic levels, not switching power, plus the charge point maintains the right control pilot signal, so the car should know that it is connected, but that no charge current is being advertised, so it should wait for an indefinite period for the control pilot to start advertising.

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I thought EV chargers and systems were still in the Betamax / VHS tussle, but now I think they are still at the super 8 cine film stage with "some way to go"

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51 minutes ago, Jeremy Harris said:

Was your charge point installed with an OLEV, or other, grant? 

 

Yes it was done via a Scottish grant. 

 

56 minutes ago, 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. 

 

Thanks, I will give that a go when I next use the car. 

 

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16 minutes ago, ProDave said:

I thought EV chargers and systems were still in the Betamax / VHS tussle, but now I think they are still at the super 8 cine film stage with "some way to go"

 

The standards have been in place for a while now, and haven't really changed a great deal from the original J1772 standard that first saw the light of day over 20 years ago.  The issue seems to be that car manufacturers aren't consistent in their interpretation of the standard, and don't stick to it rigidly enough.

 

For example, the control pilot is an analogue signal, with a 1k source impedance.  Initially this signal sits at +12 VDC, and when a car is plugged in, the car loads this line down, reducing the voltage to +9 VDC.  The charge point senses this change, and starts a +/-12 V pulse train on the control pilot, at 1 kHz, with the duty cycle indicating to the car the maximum current that is available (the advertised current).  The car then signals to the charge point that it's ready to accept charge, by loading the control pilot further, so that the positive going part of the pulse train is loaded down to 6 V (the negative going part has a diode to PE in the car, so still swings to -12 V).

 

Some cars ignore the negative going part of the pulse train (which is there for safety reasons) and will work with a charge point that only sends out a 0 V to +12 V control pilot.  Some cars work properly and require the -12 V part of the control pilot signal to be there.  The car is supposed to wait indefinitely for the charge point to turn on power after the car has signalled its acceptance of the advertised current, but at least one car doesn't (the model I have).

 

If all manufacturers rigorously implemented the spec, as defined in IEC61851 then I don't think there would be any problems.

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So we need a trading standards input to force them to recall the cars and make them comply?

 

Imagine if they were non compliant with some other motoring standard that actually made them unsafe? I bet they would act then.

 

Nothing I hear particularly encourages me to get an EV at the moment.  I just know it will come with a certain amount of unnecessary grief.

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Trading Standards can't even make a tiny dent in the vast number of dangerous bits of kit being imported to the UK, more often than not with fake approval marks, so I doubt they are going to have the resources to go after car manufacturers (and charge point manufacturers) who are selling stuff that's non-compliant.

 

A bigger issue, in terms of safety, is charge point installers not installing charge points in accordance with the provisions of Section 722 of BS7671:2018.  There are a LOT of non-compliant installations, as installers seem very keen to avoid having to install an earth electrode, and are using all sorts of dodges to pretend this isn't needed.  You and I know only full well about the risk a PEN fault presents to a big lump of metal outside, connected to a TN_C-S/PME  provided PE presents, but nevertheless it's still fairly common to find that installers are ignoring this, or using some sort of magic box to pretend that an earth electrode isn't required.

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The draft of the 1st amendment to the 18th edition is out for review.  Just 15 pages updating the requirements for EV charge points. https://electrical.theiet.org/media/2332/amendment1_read-only_final.pdf

 

I hope the situation matures soon.  By the time I buy an EV I expect to be able to plug it into ANY public charge point anywhere, and to be able to charge it at home under a regime that I dictate that will be either time of use or based on solar PV generation.  Those don't sound like particularly strange requirements if we are to have better controlled use of available grid power, but I see no sign that it is possible.

 

At the moment there is a 4PM to 7PM shortage of power.  How many EV's will be arriving home at say 5PM and plugging in the chargers just when they are not wanted, and with no easy timer function, most won't be bothered to say "oh I'll go out at 9PM and plug it in"

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27 minutes ago, ProDave said:

The draft of the 1st amendment to the 18th edition is out for review.  Just 15 pages updating the requirements for EV charge points. https://electrical.theiet.org/media/2332/amendment1_read-only_final.pdf

 

 

Thanks, it looks like the changes proposed to Section 722.411.4.1(iv) will enable one of the magic box solutions to be used instead of an earth electrode.  That bit is worded almost as if the manufacturer of the device (matt-e) wrote it. . .   It also looks as if they intend to leave the door open for other protection methods, from the wording of 722.411.4.1(v).

 

Not wholly sure this is as safe as using an earth electrode, TBH, as they are assuming the same degree of reliability for the voltage sensing device as for an earth electrode and its associated connections.  Given that we know that protection devices can, and do, fail in ways that renders them inoperative, it seems that there is still a risk, especially as there's nothing in there about how these devices can be tested.

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6 minutes ago, Jeremy Harris said:

 

, especially as there's nothing in there about how these devices can be tested.

That will be amendment 2 next year.

 

If anyone thinks I am paying for a new book just for that amendment, they can think again (I will print those few pages)

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7 minutes ago, ProDave said:

If anyone thinks I am paying for a new book just for that amendment, they can think again (I will print those few pages)

 

 

Me too. . .

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@newhome Tale a look at the Ohme charging cable - they do a version that plugs in to your existing chargepoint to make it ‘smart’

 

also has direct integration with octopus agile so you can say to the cable ‘only charge when cheap’ and don’t have to worry about plugging in at specific times. 
 

There was/still is a deal where you can the cable discounted to £200 when buying via Octopus (need to have at least started the switch to them before you order)

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10 minutes ago, MrMagic said:

also has direct integration with octopus agile

 

Thanks, but it seems that my plan to move to that tariff is a no go as they don’t have a smart meter for 3 phase 😕

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In that case the cable will just act like a normal smart charger, i.e. set timers, charge levels etc

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What eV are you thinking of going for? If I'm not mistaken, most provide the ability to set charge times anyway, negating the need to to it at t he meter end? 

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1 minute ago, jamiehamy said:

What eV are you thinking of going for? If I'm not mistaken, most provide the ability to set charge times anyway, negating the need to to it at t he meter end? 

 

I've got one already. It's a 2015 Mitsubishi Outlander PHEV hybrid that doesn't have the ability to set charge times. I don't worry about when it's charging now as I'm on a flat rate but had I been able to switch to Octopus Agile charging during the 23p - 27p rate would be prohibitively expensive. It's moot now though since I can't get a smart meter and my current prices are fixed until September and I don't think I will better them. 

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9 minutes ago, jamiehamy said:

What eV are you thinking of going for? If I'm not mistaken, most provide the ability to set charge times anyway, negating the need to to it at t he meter end? 

 

Some do have built in charge timing of some sort, although some don't.  My Prius Plug in had a built in charge timer, but I'm pretty sure that the Outlander that @newhome has doesn't. 

 

The effectiveness of the built-in charge timers is a bit variable.  The BMW i3 I had used a really bizarre system where you could only set a scheduled charge if you also set a defined departure time.  If you didn't need to depart at the set time (say, 07:00, the end of the winter E7 period here) then the car would waste power preconditioning the battery.  Thankfully, the i3 worked OK with a charge point with a time switch, so I never had to use the pretty useless onboard timing system.

 

The Tesla Model 3 has a scheduled charge timing system that's almost as bad.  It allows the start time of a charge to be set, or the end time of a charge to be set, but not both.  This can be very annoying, as if a start time is set for the start of the E7 period, but the car needs more charge than can be delivered in 7 hours, it carries on charging at the peak rate until it's charged.  Likewise, if an end time is set the car may start charging before the cheap rate starts.  The final annoyance is that the Model 3 doesn't comply with IEC61581, so won't respond to a timed or smart charger that tries to control when the car charges.

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On 09/02/2020 at 10:09, newhome said:

 

Thanks, but it seems that my plan to move to that tariff is a no go as they don’t have a smart meter for 3 phase 😕

That's a really useful insight. I'm on Octopus and aiming for their Smart meter to get the 0030-0430 cheap period for car, immerser etc... At the same time I'm getting a firm quote to upgrade our 100A connection. We have a fully electric house, a Nissan Leaf on order (and probably another EV in years to come) and second house to be built in garage - so 3 phase is only realistic option. But that would scupper the cheap leccy plan! A friend is going to lend me a load monitor to see what we actually draw /when. If 3 phase rules out Smart meter then we'll need to work on a Plan B. 

 

The market and governments are so far behind the curve its laughable. Lucky that neither Boris nor Nippy will be in power when it's becomes clear net zero can never be met because their governments were so slow to act. 

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16 minutes ago, jamiehamy said:

That's a really useful insight. I'm on Octopus and aiming for their Smart meter to get the 0030-0430 cheap period for car, immerser etc... At the same time I'm getting a firm quote to upgrade our 100A connection. We have a fully electric house, a Nissan Leaf on order (and probably another EV in years to come) and second house to be built in garage - so 3 phase is only realistic option. But that would scupper the cheap leccy plan! A friend is going to lend me a load monitor to see what we actually draw /when. If 3 phase rules out Smart meter then we'll need to work on a Plan B. 

 

The market and governments are so far behind the curve its laughable. Lucky that neither Boris nor Nippy will be in power when it's becomes clear net zero can never be met because their governments were so slow to act. 

 

 

Bear in mind that you can only put around 28 kWh of charge into any EV during the 4 hour Octopus Go off peak window.  That's around 100 miles or so, depending on the weather, which may or may not be enough.  I quite often need to put close to double that amount of charge into my car overnight.

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2 hours ago, Jeremy Harris said:

 

 

Bear in mind that you can only put around 28 kWh of charge into any EV during the 4 hour Octopus Go off peak window.  That's around 100 miles or so, depending on the weather, which may or may not be enough.  I quite often need to put close to double that amount of charge into my car overnight.

It's a good point. We're buying the car to commute - the instances of us returning home near empty should be fairly few (60mile commute vs 120m+ range) It will get charged each night regardless so probably 7/10 times 28kWhs will be enough. For weekends when we're often all over the place we've got the *cough 2.7Bi Turbo V6 petrol Audi...  😉

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6 hours ago, jamiehamy said:

The market and governments are so far behind the curve its laughable.

 

There appears to be little appetite for producing a 3 phase smart meter as it's considered to be a niche product. I read that 3 phase is pretty standard in Germany so why they can't adapt a 3 phase meter from there heaven knows. Apparently the government target is to offer all homes a smart meter by the end of this year. Not holding my breath! I'll probably be blamed for having 3 phase to begin with! 

 

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Octopus have replied to my query as follows:

 

Thanks for getting in touch. At present we are just taking down customer details who are interested in this and then we will look at demand and come up with a plan. Would you like us to add your details to be contacted?

 

Then they have asked the following questions. Not sure I know the answer to all of them. Some of them sound like the sort of questions you would ask a business. 

 

If you do want to be added we need the answers to the following if possible?

Where is the location of the electric meter?
Will we have access to the main fuse? 
Is there space for a smart meter to be installed? The required space is 600mmx600mm.
Does the property have any PV/Batteries/Chargers?

Are there any high loads at the property?
If so, what is the shutdown sequence of the high loads?
Can a duty electrician be available to aid shutdown and start up? 
Does the property have any storage heaters?

Are there any time switches?
Are there any other management systems with utilise CT clamps?
Are there any alarm systems that may need to be reset? 

This will help us answer if it's possible.

 

What’s the thing about the high loads, shutdown sequence and duty electrician? I have a 24kw boiler that runs for about 2 hours a day which is why I have 3 phase. I presume that doesn’t count as a high load, and clearly I have no shutdown sequence or duty electrician. 

 

I don’t have storage heaters so can answer no there, as I assume that a TS doesn’t count, but what are time switches and CT clamps? I assume I enter no there too? 

 

 

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