Scheduled three-pin charging?

[samoht]

I've just got a Citroen e-C4 (which I like a lot). I only do c. 5k miles a year, or 100 miles a week. As such, a three-pin charger seems quick enough for my needs, and I have a good quality mains outlet available which isn't getting warm doing so.

I'd like to take advantage of cheap-rate overnight electricity, and have found such a tariff which is cheap midnight - 5am. Five hours times 2kW = 10 kWh a night, times five nights a week = 50 kWh which is a full charge ready for the weekend.

However, while the Citroen allows me to schedule a start time for charging via its infotainment, it doesn't apparently support setting a scheduled end time. I want to set it to charge only in the 00:00-05:00 cheap rate window, i.e. to stop charging at 5am daily and start again at midnight.

I'm a little concerned about using a separate mains timer, as it needs to support a fairly hefty current, and I'm not sure that cutting that off abruptly is a good idea for sensitive electronics.

The ideal thing would be if the three-pin charger itself had start and end charging times, as it could end the charging session gracefully. However again I can only see ones that support deferring charging start, none that allow you to set an end time. Having it built into the charger would mean it was at least intended for handling such a power.

Does anyone know of such a three-pin charger? Or alternatively of a mains timer suitable for this purpose? It looks like Ohme used to offer a 'three pin charger' with scheduling, but they've discontinued it.

I know that I could get a 'proper' 7kW home charger, but it feels like a waste of an extra ~£1k on what's meant to be a money-saving exercise, when I will very rarely need the higher charging speed.

Apologies if this is a dumb question, I'm new to e-motoring

[James6112]

Hi
If a smart plug is safe (eg Tapo says 13A)
Is there a setting on the car, which tells it to charge when the power is connected?
So come on at midnight.
Can’t see turning it off being a problem.

Eg wife’s Phev, can plug it into the car/socket
Then turn on the 3pin plug
Works fine.

[TheDeuce]

We use TCP smart plugs all over our house, they're rated at 13a which should be fine switching a granny charger which is just 10a.

The electronics in the smart plug will be protected from back EMF from the switching relay by a suitable diode on the relay circuit. Switching off a high induction load will slowly degrade the contacts within the relay switch, but no more so than switching off manually at the wall would damage the contacts of the wall switch. Either way, you're using a switch to break the circuit, same load, same switch rating...

[samoht]

Many thanks, will look at smart plugs, seem like just what I need

[somouk]

A lot of cars don't seem to support a scheduled stop time but only a start time and a state of charge. Really annoying to be honest but the UK is unique in its power system with cheap overnight electricity I'm told which is why manufacturers don't bother doing it.

[Ardennes92]

Can’t you set the car charge limit eg 20% charge on day 1, 40% on day 2 etc with a common start time of 00:01?

[samoht]

AIUI the e-C4, and all the Stellantis 50kWh EVs, support neither a charging max limit nor a charging end time, only setting a deferred start time. But once you start charging, as far as Stellantis are concerned, you're going to continue until the battery is 100% charged.

[Michael_B]

somouk said:

A lot of cars don't seem to support a scheduled stop time but only a start time and a state of charge. Really annoying to be honest but the UK is unique in its power system with cheap overnight electricity I'm told which is why manufacturers don't bother doing it.

In Switzerland I have cheap electricity (35% price reduction) 22h-7h on weekdays, and 22h-17h at weekends.
At my French house off-peak (45% price reduction) is 01h30-7h and 12h-14h weekdays and all weekend from midnight Friday til midnight Sunday.
Tesla allow a scheduled start and final SoC, so I use that. The car even suggests what you programmed when last at that location, which is useful.
Knowing the charge rate in both places makes it fairly simple to set a SoC which corresponds to the desired switch off time, though I’m usually awake by 7 so can always turn it off remotely via the app.

[samoht]

^ thanks, I was gonna say, I can't believe other countries don't have more power supply than demand in the middle of the night, especially France with its largely nuclear fleet running 24/7.

The deal I'm getting has the cheap energy ending at 5am, which is a bit early for me to be waking up unless I've just got back from the far east! But should give me enough cheap hours to charge fully between weekends.

The Tapo P100 said:

EV charging is not supported since it typically requires higher power, and its charging current exceeds the rated current of the plug

however

The Tapo P105 said:

Support Higher-Power Appliances – Schedule your kettle, coffee maker, and toaster to enjoy a "preset" breakfast

I have ordered a P105 from John Lewis, I'll post back how it goes.

https://www.tapo.com/uk/product/smart-plug/tapo-p1...
https://www.tapo.com/uk/product/smart-plug/tapo-p1...

[Michael_B]

samoht said:

^ thanks, I was gonna say, I can't believe other countries don't have more power supply than demand in the middle of the night, especially France with its largely nuclear fleet running 24/7.

In Geneva our elastic trickery comes from the Chancy-Pougny dam on the Rhône about 2km from the house. Rivers around here tend to flow 24/7 as well

[barryrs]

I have a BG Smart Socket in an external weatherproof enclosure which is programmed to turn on and off to correspond with the cheap hours.

[covmutley]

Dont disagree with the above, but just saying that if you just leave it and switch it off at say 7am, its only another couple of hours of charging, so pennies.

Plus the next night charge, you willl get to your desired state of charge sooner, so it might cut off at 5am anyway?

I suppose I'm saying, just do what's easiest, unless the pennies matter to you

[Herbs]

Personally just let it run as its still far cheaper than petrol, plus its better to have a full charge if you ever need it in an emergency.

Also, if you are only using it a little, it will never be charging from empty so the chances are it will reach 100% in the window and turn itself off anyway.

[samoht]

I think it's correct that the savings are relatively small, in that the amount of electricity you can draw through a three-pin charger in five cheap hours a night is relatively limited anyway, so paying a higher rate for some of that doesn't add up to a vast amount per year.

For 100 miles a week at 3m/kWh, I estimate it would add £40 to my monthly electricity bill on a standard tariff, or £20 a month to move to a split-rate tariff and do all my charging in the cheap hours. So it's only c. £240 a year total saving by scheduling the charging... which isn't a vast amount, but is enough to be worth doing and worth paying say £8.99 for a Tapo plug.


Just in case anyone else is looking for this, I found two additional possibilities in addition to the smart plug recommended above.

1) An extension cable that integrates a timer, either directly set on the unit or configured via an app - https://toughleads.co.uk/collections/heavy-duty-13...

2) A program which promises to let you set end times and/or maximum charging percentages for Stellantis EVs https://github.com/flobz/psa_car_controller - it would appear that the cars may actually support this, and it's just the infotainment and official app which don't.

[clockworks]

I didn't realise that some cars don't allow fully-scheduled charging.

My 2021 XC40 plug-in hybrid allows scheduled start and stop times via the app, so I set it to come on at 00:30 and go off at 04:30 to match the Octopus Go cheap rates.

Set it once, and forget about it. I just plug in when I get home. If the car is plugged in, it'll just charge at the scheduled time.

As a backup, and to disable the charger outside the cheap rate window, the granny lead is connected via a Tapo P110 smart plug. This is set to come on at 00:20 and go off at 04:40. Again, this is an automatic schedule, and it should never switch on or off while the car is actually charging - unless the software fails.

If I want to charge the car in an emergency outside the window, it's just a couple of button presses in the Volvo and Tapo apps to override the schedule.

The P110 has the added benefit of monitoring the actual amount of electric that's put back into the car. Makes tracking consumption/running costs a lot more accurate.

[lost in espace]

I was on Octopus Agile wtih my 3kwh charger, but moved into rental and lost the charger. I moved onto Octopus Tracker, I just plug the granny charger in when daily rates are low. Would recommend.

[ZesPak]

clockworks said:

I didn't realise that some cars don't allow fully-scheduled charging.

The fact that Stellantis apparently still doesn't do "max charging limit" is odd to me.
There's obviously a reason the industry had to wake up when the Model S launched over a decade ago :/.

As for the OP, I wouldn't mind the "cut off", the car should be able to handle just being disconnected no issue.
Find a sturdy enough timer for the plug and you'll be fine.
I'd say a lot of these timers would be rated high enough, but most are used for things like christmas lights and the like, so make sure it's rated high enough.

[samoht]

The Tapo P105 is now working nicely, I'm leaving the car plugged in on the drive and it gains about 25% charge each night in the cheap overnight period with no interaction needed.

ZesPak said:

The fact that Stellantis apparently still doesn't do "max charging limit" is odd to me.
There's obviously a reason the industry had to wake up when the Model S launched over a decade ago :/.

Indeed. The thing is, making software is a totally different skillset from making cars, and big OEMs like Stellantis are about as adept at programming as they would be at, say, creating a blockbuster film. Tesla has the opposite problem, a bunch of programmers trying to make cars, but they at least managed to hire in enough car people so the wheels don't normally fall off.

[ZesPak]

samoht said:

Indeed. The thing is, making software is a totally different skillset from making cars, and big OEMs like Stellantis are about as adept at programming as they would be at, say, creating a blockbuster film. Tesla has the opposite problem, a bunch of programmers trying to make cars, but they at least managed to hire in enough car people so the wheels don't normally fall off.

It's funny how we saw so many manufacturers struggle getting an interface in their car as cars got more and more functionalities, and imho almost none of them really got it right. Nearly anything past 2005 is just a horrific experience imho. The worst ones we had were Alfa and Jaguar. I just don't bother changing the time to DST on the Alfa as it's hard to figure out without a manual.

I know Tesla gets a lot of heat for the "glued in tablet", but in terms of using the extensive array of features the car has, it's night and day coming from anything that isn't the Google system.

The issue with EV's I guess is that so much of the user experience is software these days, "filling up" as per this thread, accelerating and braking (converting pedal input into forward motion and using engine braking). Hell, I understood that the reason the Plaid accelerates faster than it brakes is because the Tesla software has more and faster control over the motors than the Bosh ABS system.

[essayer]

To be safe, I would unplug the granny and the Tapo each day and check for any developing heat damage. The charger plug should have overheat protection, but the Tapo may not