Charging from a granny lead, dangers?🔥🤔

[tsedge]

I was particularly struck by the people saying what low cost per Kwh they had, but not considering that the cost of their daytime domestic energy use had gone up in proportion.

That can pay off - we have a cheap night rate and more expensive day rate on Octopus Go and it is cheaper for us: we do 10,000 miles a year and time-shift washing machine and dishwasher. But everyone's usage is different so it pays to work it out.

 

[Rolfe]

I have nothing more to add. Good luck with your decision.

I haven't really made a decision yet. I've only had the car for a week. I need to weigh up the pros and cons while living with the granny charger in the real world. A friend who has had a Leaf for nearly three years says he used the granny charger for a year because of complications and difficulties with the installation of the wall box he had ordered. He didn't have any problems with it but wanted the fast-charge capability because of his lifestyle.

I think you're right that there will be more and more people relying on these chargers going forward, and it will be interesting to see what happens.

That can pay off - we have a cheap night rate and more expensive day rate on Octopus Go and it is cheaper for us: we do 10,000 miles a year and time-shift washing machine and dishwasher. But everyone's usage is different so it pays to work it out.

I think it needs careful consideration, and as you say a willingness to shift other consumption on to the cheap tariff time. I'm sure it does work out well for some, particularly those who are out all day leaving an empty house. I was just somewhat amused by people who didn't seem to have thought about it at all.

That's actually another reason the granny charger suits me. I'm in all day and I don't really want to set appliances to run overnight. I'm not going to be charging the car every night, nowhere near. It doesn't make sense for me to arrange a cheap night rate I might use once or twice a week and make all my daytime consumption more expensive. So the longer hours the granny charger spends taking power aren't such an issue for me.

 

[Deleted member 10041]

People use granny chargers without incident, but some problems with wiring don't/won't manifest themselves till further down the line after a period of continued use.
I don't do high mileage about 7000-8000 miles a year but the overnight rate works for me, I have an Ohme charger £750 after the rural grant I mentioned to you,
I'm on octopus intelligent 2330-0530hrs at 10p a KW, they also chuck in other hours here and there. I'm 39.4p a KW during the day.

It's whatever works for you as long as your happy with your decision.
I prefer the wall charger, for me the added safety, efficiency and convenience is worth the £750 I paid.

Again each to their own.

 

[Rolfe]

As I said, I haven't made up my mind yet, intending to live with the granny charger for a few months to see whether its charging capabilities keep up with my motoring needs.

All these comments are extremely helpful, with a lot of things to weigh up, and I'm grateful to everyone who has taken the trouble to weigh in on it.

 

[IanMK]

Regarding my charger installation quotation of £400.

10m of supply cable (6mm SWA cable with integral cat 5), 32A MCB and other ancillaries accounts for £100 of that. We can't all get 'mates rates' or 'cash' deals. Dreaded VAT is £67.

Installation involves more than simply screwing a few bits to the wall. I am also paying for the electrician's training, knowledge and expertise, the tools of his trade (and other expenses), his travelling time, his time to perform the safety testing of the new circuits and the time it takes to prepare and submit the required paperwork (notifying the DNO and local building control) and providing his installation certificate. I think it's good value for what could reasonably be a day's work. It may not take a day but I can't expect him to make up work at short notice to fill in small gaps that appear in his work day.

Qualified electricians do what they do in order to earn a living and provide for themselves and their dependents. Please don't disrespect them by trivialising their role and expecting something for nothing.

£135 installation? Give over!

 

[Rolfe]

And surely, having just splurged £30K on a new car, why would anyone baulk at paying an electrician a fair rate....

 

[Lovemyev]

I think the vote for shelling out for a wall box and should you go for a time of day ( of peak ) tariff or NOT can be rejected or accepted under the same reasoning really, by the answer this simple question ?.
WHAT IS YOUR PERSONAL USAGE CASE ?.
If you are making short trips and only covering a few thousand miles a year, then it's probably fair to say that a Granny lead and a standard rate tariff is likely to do the job.
If you are a person covering say .......... 10,000 and more and are in position where you can load shift your usage into a "off - peak" tariff, then the greater usage can justify the outlay for a wall box and an accompanying off peak tariff I think.
Regards to the Granny lead not carrying out warnings regarding its safety in use in every home.
Well personally I think this takes a lot for granted with regards to the safety element here.
The owners manual just states that it should be used in conjunction a suitability rated socket outlet.
Personally I do find this statement takes in a lot for granted.
There are just too many factors to list, that can influence the suitability of using a Granny lead over longer periods of time etc etc.
It makes the assumption that every single property has the same age electrical system installed to the latest spec's and latest reg's for a start.
Of course I think we all except that this is clearly incorrect and is a very general statement.
You could be living in a new build property with a completely new wiring system being supplied by a 100Amp DNO cut out fuse and have no issues charging from either a Granny or a wall box.
On the other hand, you could be living in a older type property that has received NO electrical updates and is on a looped supply from the house next door and has a 60 Amp fuse protecting the property.
They both have three pin socket outlets inside the property, which would you consider safer to plug in your Granny lead ?.
Not two houses are ever the same, this where the issue can arise !.

 

[Rolfe]

All excellent points. (My house is 27 years old and its cut-out fuses are annoyingly hair-trigger. Any time a light-bulb pops, that entire circuit trips. Plug in a faulty appliance, and the same thing happens.)

Personal usage? That's the biggie. I used to do 12,000 miles a year but that was when I had a round trip of 24 miles to work every day. I retired not long before covid struck, and my mileage has been artificially low since then. Hence, suck it and see.

I'm also conscious that I'm in the house all day most days, with various bits of electrical equipment running. That weighs against an Octopus-type tariff to some extent.

 

[Lovemyev]

All excellent points. (My house is 27 years old and its cut-out fuses are annoyingly hair-trigger. Any time a light-bulb pops, that entire circuit trips. Plug in a faulty appliance, and the same thing happens.)

Annoying of course, but a good indication that the system is doing its job right !.
I am going to make a pure guess that your main cut out fuse will be rated at 60 Amps ?.
Not the one in the C.U. ( fuse box) the one on the main supply cable before your meters.
It will sealed in place with a wire and crimped with a lead tag seal.
It belongs to your local DNO network supplier and should NOT be touched, other than by them !.
I used a Granny to charge our 2015 VW PHEV for about seven months, before having a wall box installed.
How did I find it ?.
It worked just fine of course, but after good few hours of charging, the back of the three pin plug did get warm.
Not stupid hot, but there was heat present for sure.
The socket I used to charge from, was on its own dedicated circuit.
I used this Granny to gain a charge when we travelled away for a short holiday, with the same affect at three different addresses.
Heat was present at the plug top.
When the wall box was finally installed, I retired the Granny lead to the wall of our garage.
Another thing worth considering is this, now you have a full EV if this is your only mode of transport and your single point of charging is your Granny lead, what happens if that unit fails for some reason ???.
Are you close to a public charger by any chance ?.
Owning an EV tends to puts you in the state of mind of :- “Do I have a back up / fall back plan”.
Many EV owners tend to carry a 12 volt battery booster packs for example ( I do ).
I also carry a public type 2 charging cable, plus a spare wheel, and a 10mm spanner .

 

[sha66ir]

I have no choice but to 100 percent rely on granny charger since my nissan leaf days.

 

[Rolfe]

I have not detected any heat in the plug or the socket during charging. I will continue to check for this.

The fact that I have back-up charging is part of my reasoning for not rushing into a wall box right now. There is a public charge point about five minutes walk from my house. If I ever need fast charging because I'm planning a long trip the day after having brought the car back with a low battery, it can have 45 minutes on that.

I also have very kind neighbours only about 50 yards away who have an exterior wall box and who have offered me the use of it if I need it. (I'll have to find out how much electricity that will take from their system so I can offer appropriate payment, if I ever have to take them up on it.)

Amusingly, if I walk the five minutes to the public charge point, I pass the home (and business adress) of the guy who is the licensed and approved installer for wall boxes in this area!

I have no choice but to 100 percent rely on granny charger since my nissan leaf days.

How long has that been, and how have you managed?

 

[sha66ir]

How long has that been, and how have you managed?

Have been charging via granny charger since 2019.
First nissan leaf, then the ZS and now MG4

 

[Rolfe]

Do you find it's fast enough to keep up with your regular mileage? Do you have to use public charge-points much?

 

[siteguru]

FWIW, this is the wall box I have. (And as I've documented elsewhere, I ended up getting mine, inc fitting, for nothing ... in fact I even made £160 profit on it).

Amazon product ASIN B0B13THHHC

 

[Cocijo]

People use granny chargers without incident, but some problems with wiring don't/won't manifest themselves till further down the line after a period of continued use.
I don't do high mileage about 7000-8000 miles a year but the overnight rate works for me, I have an Ohme charger £750 after the rural grant I mentioned to you,
I'm on octopus intelligent 2330-0530hrs at 10p a KW, they also chuck in other hours here and there. I'm 39.4p a KW during the day.

It's whatever works for you as long as your happy with your decision.
I prefer the wall charger, for me the added safety, efficiency and convenience is worth the £750 I paid.

Again each to their own.

Your Octopus rates should reduce from tomorrow.

 

[sha66ir]

Do you find it's fast enough to keep up with your regular mileage? Do you have to use public charge-points much?

On the mg4 it adds around 15% over the 4 hours off peak window.

It's been enough for us so far.

Almost every weekend we do around 130 miles with 80% charge and usually end with 20-30% remaining at the end of the journey.

Been adequate for us.

 

[Rolfe]

So you only use the car at weekends, and schedule it to charge for four hours every night during your cheap tariff period? That does seem to be an economical way to do it.

Do you keep it plugged in to the granny charger the whole time, or do you unplug it during the day?

 

[Davn]

From the comments above, I'd say it's justified so you don't have you house set on fire.

Really what comments

 

[sha66ir]

So you only use the car at weekends, and schedule it to charge for four hours every night during your cheap tariff period? That does seem to be an economical way to do it.

Do you keep it plugged in to the granny charger the whole time, or do you unplug it during the day?

We do use the car throughout the week for short journeys like taking our toddler to toddler groups, gym, shopping etc. But those journeys are no more that 7 miles each in total.
When we get back home I plug it in till our next short or long trip

 

[CarlMG4]

I've been charging with the granny lead on a fused outdoor extension, plugged into the kitchen socket circuit (dedicated) overnight, after our dinner-making usage has stopped.

Our wiring is 2 years old, has 100a breaker, and I turn the charger off if we use the kettle. Everything else on that circuit is off. There has been no heat in the extension or the plugs. The kitchen has a smoke detector. The smart meter is showing 2kwh pull from the charger, the car is showing 1.87kwh charging at the car.

It's costing around £20 for 200 miles usage for the week. Off peak at 10p/kWh it would cost less than £7.

This is only a temporary measure until we get the OHME installed. In which case I'll switch over to Intelligent Octopus tariff, and charge with the 7kw charger in the 6 hours off peak.

My day rate will increase by 20%, but we are fairly low home users, and can timeshift the washing machine to off-peak to save on that.