Using a granny charging cable at 10A is perfectly OK. I regularly use one when staying at our holiday lodge on OVO's Charge Anytime. The car is on their compatible list. Since you can charge any time (as the name suggests) there's no time restriction to getting the 7p/kWh.
The only problems with granny charging occur when people try charging above 10A, as 13A sockets are not designed to sustain a current of 13A for extended periods. The same applies to using an extension lead.
We have some Tapo smart plugs at home for automatically turning things on and off at set times. They can be set up and controlled by an app on your phone. They also show how much power is passing through the plug and how much energy was used.

 

Totally untrue sweeping statement.

Let me amend it for you....

Using a granny charging cable at 10A is perfectly OK, until one day you find that the socket you've been using has slowly but surely over 6 months deteriorated to the point where the internal resitance has built up to an excess and it's sets on fire (or at least smokes horribly). I regularly use one when staying at our holiday lodge on OVO's Charge Anytime. The car is on their compatible list. Since you can charge any time (as the name suggests) there's no time restriction to getting the 7p/kWh.
The only problems with granny charging occur when people try charging above 10A, as 13A sockets are not designed to sustain a current of 13A for extended periods. (again totally untrue - whilst many problems WILL occur over 10a - when my socket set on fire it was charging at 10a) The same applies to using an extension lead.

The fact is thousands of people charge on a granny fine for a very long time - but there have been numerous fires and melted sockets using a granny. Your best bet is to fit a proper charger, but if that's not possible, just make sure that you set the charge rate to no more than 10a during the day if you can occasionally go out and check things are ok and perhaps 8a overnight which will reduce the heat build up in the plug. Get an electrician to check the socket you are using is is perfect condition with almost no internal resistance, and just use common sense. I would not use a timer in the socket for all the reasons stated above. The standard domestic socket is simply not designed for high loads for those kinds of time periods.......

 

why do I have to set a departure time to be able to schedule changing?

Are you sure about that? I have an e-niro (as you do, apparently) and the "departure time" setting is for the climate control preconditioning. Charging timer is simple set start and end time, and the language on the display makes it clear that they assume you're setting "off peak" electricity times.
That said, I don't think you can set more than 1 charging period per day. My timer is permanently set for a night time charge and manually override it if I want to top up on solar in the day.

 

Ahh - I was trying to program it through the Kia Connect app. I was told I had to set a departure time before scheduling charging. Perhaps it is possible directly though the car?

Edit: I now just defined departure every day at the same time, and it then seems to accept the setting. Sometimes a past in IT is useful...

 

Using a timed switch in that manner is not going to do the car any favours.
An occasional loss of power is one thing but to deliberately cut the power every time you finish charging is going to damage the car and in a way that the warranty would not cover the cost of repairs.

For the very few legitimate reasons to use a timer switch it would be a completely different type of device and would involve a fair bit more than plugging it in.

Gaz

 

Using a time switch to switch on a granny lead is fine. On turning on the EVSE will tell the car it's here so the car can say turn on the power please.
Turning off with a time switch is likely to end in tears, breaking a 10amp current is likely to lead to arcing with the potential of high voltage spikes, toasting a granny lead is unfortunate, damaging the cars OBC is not good.

The switch off sequence is a slow,relatively, ramp down of the current from the car so there is no danger of arcing.

 

Indeed, I've seen a couple of failed granny leads from this and someone here had similar, with, IIRC, serious additional damage, I think to the charger in the car. Chargers present a pretty reactive load when suddenly turned off, and although they all have built-in protection from the spikes this can cause, those surge protection devices degrade more and more with each spike they shunt to ground. Over time this can cause them to fail, which is why domestic SPDs have both indicators to show when they are worn out and their own MCB to trip and so take them out of circuit when this happens. The surge protection devices in the charger most probably don't have this protection as there is no expectation that they will need it, they normally only have to handle a few, probably infrequent, power cuts through the life of the vehicle.

 

This then brings up the next question: which is the proper way of stopping charging from the car (I know how to use the app) when using e.g. the granny charger?

I will try the manual, but it it in French and my French is very poor.

 

Best bet is to stop the charge from the car itself. Not sure how the Kia does this, but some cars just stop charging when unlocked, some have an option to do this from inside the car and some have a stop button by the charge port. This being the Kia bit of the forum hopefully someone with detailed knowledge may respond.

 

Thank you Jeremy!!

Yes, the socket that almost set fire was a brand new, MK - I'd been using it for about 6-12 months.

So no I am not an "EV hater" (stupid comment there Hangnail999) as I've had one for 3 years and love it - I am just honest and not blinded by ignorance.

UK Domestic sockets are NOT designed to take very high loads for a very long time - both of which happen charging an EV on a 3 pin.

Where possible use a proper EVSE, otherwise, if you can, turn down your input current (usually via the granny or the car) to about 8A and you will probably be ok - note the use of the phrase probably.

All those that are willing to GUARANTEE using a granny is safe, I assume you are willing to put your money where your mouth is and offer to pay to rebuild anyone's house that burns down following your "advice"?

Didn't think so.....

Ultimately nothing in life is safe, using a granny lead is probably safer than base jumping...... just be aware there is a small risk and know what it is.

 

So no I am not an "EV hater" (stupid comment there Hangnail999) as I've had one for 3 years and love it

I never said you were a EV hater.
You don't have to get defensive.
Please keep the discussion civil without the emotion.

 

Only thing I'd add is that installing an EV rated 13A outlet isn't that much cheaper than installing a charge point, given the additional circuit protection that is a mandatory requirement (as in Section 722 of the regs, etc).

 

Over here, regularly using a granny cable to charge with isn't legal any more.
If the outlet is to be regularly used to charge an ev, you need a wallbox. We had a brief period where you could use a dedicated outlett, but that fuse could only be used for that outlet, you could only have that one outlet too, nothing else. And of course the fuse had to be the right kind for ev charging (DC monitoring too).

Now you need a wallbox. No way around it if you are being a ev now.
But you are allowed to use a granny sporadically, while monitoring it.
I would guess it will get to this over there too, as evs get more common. Ev charging is the biggest fire hazzard there is with ev, and it usually isn't the car that will start burning...

 

On my Soul, I stop charging by unlocking the car, although usually it has reaced target SoC and stopped anyway.

When on holiday a while ago, I tried the granny charger just to test it out. Set to 6A and checked after an hour, plug and socket had become quite "warm". Tried another nearby socket of same age and type and it stayed stone cold even at 10A. My conclusion is use an EVSE if possible and, if you have to use your Granny, keep a very close eye on her.

 

FWIW, the lowest allowable charge current is 6A, which is about 1.4kW. Anything lower than that is outwith the spec in IEC61851. It's anyone's guess if the car really does drop to 2A, or it it's just some sort of issue with how it displays charge power.

 

6A is the lowest you can specify with the duty cycle of the square wave on the control pin, but as I understand it, the car is perfectly entitled to draw less current than that specified (but not more.)
The e-niro can be set via the dashboard to two levels of reduced charge current, which clearly goes below the current set by the EVSE. I have the Kia granny cable which can be set to 6A: as an experiment perhaps I should try that combined with minimum charge rate on the dashboard and see how low it can go.

 

I have always switched the car off from charging by lowering the charge % in connect. Let the system sort it out.

 

I think any electrical engineer or tech understands why it's not ideal to make a habit of disconnecting the AC side of an EVSE while under full load, at the very least in regards to the electrical contacts actually doing that task. I was curious and checked my two portable EVSEs owner's manuals from Protecta and Ratio.

.

One other side effect to dropping AC first is that leaving an unpowered EVSE plugged in for more than around 10 minutes may drain your 12V battery. If you have a BM2 monitor, try it.


Along the same lines but counter to this advice, it's worth noting that the CP pin on the EVSEs charger plug is shorter than the others with the intend that a dropped CP signal will cause the EV to immediately drop the load. The spec calls for that to happen within 100ms. The problem is that anyone can pull out an unlocked plug faster than that.

The risk here seems confined to the situation where the emergency plug unlock knob needs to be used. You'd alway want to drop the power to the charger first, especially when DC charging and at higher AC currents.

 

I have heard of people using a 16 amp immersion heater timer to switch off a granny charger?

 

They look at the switch rating which is fine. This is no different to any other switching method.
See various comments above about switching off active granny leads.

 

Thank you Jeremy, very interesting, I was unaware of any of that.
I remember reading last year that a guy had been using a granny charger with a 16 amp immersion heater switch for two years! Sounds like he's been very lucky then so far!

 

It's luck, plus the exact circumstances. For example, if the time switch turns off close to the zero crossing point of the mains cycle then there probably won't be any spikes (because the supply voltage is zero at this point). Also, if the car charger has stopped the charge before the time switch turns off then there also won't be any spikes. The problem area is when the time switch turns off whilst the charger is still pulling power, and when the instantaneous mains voltage is above zero.

 

I linked to an article on MOV's earlier . 100 to 200 surges is about it before they are toast. If you have to use a timer on a granny then switch it on but leave the off long enough for the charge to finish.
Ideally use the cars timers which turn on and off correctly.

 

That's useful to know. It's a pity that (as far as I know) you can only change the charge speed settings from in the car, with it turned on; you can't set it from the app...

 

This was a long and interesting discussion I got started here. I am now much better informed, thank you.

As the plug/socket has not felt hot to touch at 10A I am not worried but will reduce to 8A to be safe(r) and then get a proper home charger in September.

 

I'm glad I read this thread. I've been looking at getting an immersion timer for my dedicated 13amp socket/granny charger because Im planning to go on the Octopus Cosy heat pump tariff which has 3 off-peak periods, none of which are long enough if my Mini PHEV needs a full charge. Instead I think I'll plug in to charge immediately during one off peak slot, then towards the end of that I'll change the app to charge on the timer in the overnight off peak slot. Will that overcome the problem with switching off the AC mid-charge?

 

You may like to consider one of these type or WiFi switches. They have a very heavy duty internal switch which can be programmed as a time switch with the Smart Life / Tuya app. It will report back the energy supplied (kWh) as well as show the current and voltage. It needs to be mounted into it's own box. I have used a similar one for a year, first on a granny charger then on the cheapest dumb wall mounted EV charger I could find. This gives it all the intelligence I need!

Smart Electricity Usage Monitor,WiFi AT4PW 100A Din Rail Power Meter,110V-220V Digital Energy KWH Energy Monitor,App Remote Control Household Power Consumption Monitor with Digital Display : Amazon.co.uk: DIY & Tools

Shop Smart Electricity Usage Monitor,WiFi AT4PW 100A Din Rail Power Meter,110V-220V Digital Energy KWH Energy Monitor,App Remote Control Household Power Consumption Monitor with Digital Display. Free delivery on eligible orders of £20 or more.

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Have a read of the earlier posts about why this is likely to prove to be a very bad (and potentially costly) idea:

https://www.speakev.com/threads/granny-charging-advice.186124/?post_id=3638334#post-3638334

https://www.speakev.com/threads/granny-charging-advice.186124/?post_id=3638340#post-3638340

https://www.speakev.com/threads/granny-charging-advice.186124/?post_id=3638357#post-3638357

https://www.speakev.com/threads/granny-charging-advice.186124/page-2?post_id=3639974#post-3639974

 

I think you misunderstand my reference to the fridge freezer and old aircons. I am suggesting that the spikes they produce would be far larger and more frequent than the car charger time switch as they have massive, inductive compressor motors.

Given the high side of the onboard charger has some fairly beefy capacitors, I am not sure there would be much of a spike on charge current switch off especially if the car had already reached it's set SoC before the timer turns off.

Rest assured I have already fitted the EV charger CU with a surge protector which should protect me and future owners of my car.

 

No, not at all. What happens with your fridge or whatever has zero bearing on the this problem. Spikes from motors are pretty harmless, the attenuation on the cabling alone means they never get very far, most of the energy ends up being radiated (assuming the suppression is poor) or just absorbed by the inductance of the wiring.

The OBC issue is internal, not conducted EMC via the wiring. When you shut of a switched mode supply suddenly, especially one that uses synchronous rectification (as pretty much all OBCs do, because of the losses they'd suffer if they did not) then it's odds on that the time switch contacts will open at somewhere other than the zero crossing. The result is obvious, as the sudden internal field collapse means there is nowhere for the energy to go other than get shunted by the supply filter MOVs that are part of the OBC filter block. These are there to prevent internally generated spikes from punching through the gate insulation of the switching semiconductors in the OBC, so causing them to fail. It's the primary reason these MOVs are there, to deal with the unwanted consequences of a power cut whilst the car is AC charging.

Whilst these MOVs can provide a fair degree of protection when new, every time they conduct an internally generated spike to ground they degrade very slightly. Their conduction trigger voltage drops as they wear, so sooner or later they start conducting at the peaks of the supply voltage, and when this happens the very high current causes the onboard fusible links to rupture, which stops the OBC working.

It's pointless putting an SPD on the supply, for obvious reasons. The spikes in the OBC will never get to the SPD, both because the MOVs will have already shunted them to ground and becuse the OBC input interference filtering will prevent them getting up the supply cable (and the supply cable inductance itself would stop them reaching an external SPD - that's why the regs state that SPDs have to be located no more than 1.0m from the supply and ideally less than 0.5m from it).

All of this stuff is exactly why the car doesn't just have an AC lead to plug into a wall, but has a control pilot and proximity pilot safety system to ensure that the OBC always turns off gracefully, before the supply gets interupted

 

The problem is only turning off if the power is still on, The Charger (in the car) is designed so it it slowly ramps up the current when advised it can, so turning on a chargepoint is fine as it doesn't offer current to the car until its ready. Turning off is the problem. Here the car electronics are designed to ramp down the current over over a short time (its in the specs if you want to read) to prevent problems as detailed by @Jeremy Harris and are designed to be disconnected when the current is 0 and this is what the protocol does.

Unlocking some cars, pressing a button in the charger port on others, the timer in the car or chargepoint finishing, the battery becoming full, the old Type 1 connection having its button pressed etc. etc. will all turn off the cars charger and on type 2 ports unlock the plug ready for disconnection. The sudden application of an axe to the mains cable is not designed for apart from the rare powercut, the MOV's will have been designed to out last the car if only powercuts are taken into account.