Granny plugs ? For ev

[jcaan]

A quick advice for a mate.

He has an elect car but can not afford to put in an EV charger at home atm. The public chargers are costing 5 times more to charge !

Are granny chargers reliable ? Where he can just plug his 50kwh on a lead with a 13a plug which will be plugged into a socket .

Thanks for any input

 

[StephenStephen]

I'm not an electrician.

If your mate is paying a fifth of public charging rates at home, then it's worth looking at an EV tariff like Octopus Go - I and others expect to pay about a tenth as much at home (not a fifth as much)

The 2 main dangers of relying on a granny charger are overheating sockets and earth faults.
The main practical drawback is getting enough charge into the car during cheap rate time.

My EV is charging on a granny charger right now, as it does every night.

Some idea of the issues are here: https://www.speakev.com/threads/granny-cable-only-way-to-charge.188498/?post_id=3697525#post-3697525

 

[Avocet]

A quick advice for a mate.

He has an elect car but can not afford to put in an EV charger at home atm. The public chargers are costing 5 times more to charge !

Are granny chargers reliable ? Where he can just plug his 50kwh on a lead with a 13a plug which will be plugged into a socket .

Thanks for any input

I used the granny charger that came with my car for the first month or so after I got it, whilst waiting for the 7kW charger to be fitted. They work fine from a 13A ordinary 3-pin wall socket. Plug gets very slightly warm to the touch, but it's fine. It was running day and night on some occasions. Even at my day rate, still a fraction of the cost of a fast public charger.

 

[Murdochcat]

Technically he needs an EV rated 13A socket BUT thats just nonsense as the whole point of granny chargers is that they can be plugged into any 13A socket

DO NOT use any form of extension lead with it

 

[ReganAndCarter]

Don't remember Jack Regan's Granny having plugs. Ran on good old 4* and Johnny Walker.

(Yes, Avocet I know the first one was technically a Consul - before you feel the need to split any hairs. )

 

[StephenStephen]

My understanding (and limited experience) is that it's really worth checking the temperature of the plug if you're putting it into a different socket.

If I plug mine into the Toughleads extension cable specifically intended for a granny charger, it doesn't get warm.

There's another socket I plug it into sometimes which does get warm - not enough to worry about, but I do check it now and then.

 

[ericmark]

The problem with the granny charger, is many will not detect loss of PEN and automatic disconnect. Yes should use a special socket, and yes they are slow, and many EV charging tariffs are only for 5 hours, so looking at 11.5 kWh, so taking a Renault Zoe as an example, (52kWh battery. This provides a maximum range of up to 245 miles) the maximum daily trip would be 54 miles.

So for me, with distance to local town 8 miles, the 5 hours with a granny lead would do. But depends on the supplier, some want the details of the charge connector before they will give the low tariffs. But I was with British gas, who did allow me to have the EV tariff. This was 8.95p per kWh for the 5 hours, but 31.31p outside that time. I am paying now 25.37p/kWh with Octopus 24/7. So a full charge with off-peak £13.71 and with Octopus 12M Fixed £13.19. OK, unlikely to fully charge a battery from flat, but will be using electric for other things, so the cheap off-peak is unlikely to help much if charge limited to 10 amps, but will likely help at 32 amps.

All solar and battery, and all changes again.

But the main point is loss of PEN. What we hope is if there is a loss of PEN we are not using earthed items outside when it happens, most garden items are class II so don't have an earth, so not problem.

In my house I have an earth rod, but also TN-C-S supply, so the amount the house earth can be away from true earth is limited, but still can rise above 50 volts. But with a proper charge point, they can use an earth rod to monitor, and auto disconnect should there be a loss of PEN. It can also use maximum and minium voltages to cause a disconnection, but it takes longer.

The other problem is DC, a type AC RCD can stop working with DC, a type A can still work with up to 6 mA DC, so we should not charge an EV using the same RCD as any other items in the home, and the charge controller should auto disconnect if over 6 mA detected.

Technically he needs an EV rated 13A socket BUT thats just nonsense as the whole point of granny chargers is that they can be plugged into any 13A socket

This is a problem, where homes use one RCD for many circuits, as it can stop the RCD working, so needs a socket from a dedicated RCD or RCBO. The granny charger is designed for when visiting your granny or other friend, in other words, for the odd time when a proper charge controller is not available.

So what we are doing is a risk assessment, and in my home, charging an EV at the back of the house, and unplugging it before I touch the car, the only risk is to my cats, but at the front of the house, where the postman, milkman etc walk past my car, the risk is higher, maybe acceptable I don't know, but charge the car in the street, no way can you use a granny lead.

 

[gmc600]

Hi all, just jumping on this thread with some experience of my own. So I've had an EV for over a year now and only used granny lead for first few weeks or in emergencies (like when my Zappi EV charger randomly stops working but that's another story!). Some more recent experience is when I went away for 3 nights to stay at a small house that my parents own, it's quite out of the way so not a lot of rapid chargers nearby and about 90 miles from home. I was thinking of buying a toughleads extension cable as they seem to be the best available but didn't want to spend money on something I won't use more than a few times. My Dad said he had an extension cable with a thicker lead for me to use but then forgot to get it for me so just said that i can use the one that's already there, I was a bit wary about this especially as it's probably over 10 metres long! Anyway I turned the car down to 6 amps and it worked fine without anything feeling warm, also tried it at 8 amps and this was also fine. So I'm not saying it's a good idea but if you're desperate and keep checking for overheating etc a granny lead should be OK. Better if you can avoid using an extension cable of course!

Main practical issue that I found like others have said is that you can't get much range overnight, especially if limiting the current to avoid overheating, even having it plugged in for 12+ hours a day I struggled.

Ericmark - loss of PEN wasn't something that I had considered, I'll certainly be more careful in the future! I even had it parked on the street in front of the house! I was also with British Gas on that same tariff, still with them now (7.9 p at night for 5 hours), just wondering what your logic was for switching to Octopus? In my case I'm definitely making a saving with the low night rate but guess it depends very much on mileage and how much your house is using during the day etc.

 

[Avocet]

Hi all, just jumping on this thread with some experience of my own. So I've had an EV for over a year now and only used granny lead for first few weeks or in emergencies (like when my Zappi EV charger randomly stops working but that's another story!). Some more recent experience is when I went away for 3 nights to stay at a small house that my parents own, it's quite out of the way so not a lot of rapid chargers nearby and about 90 miles from home. I was thinking of buying a toughleads extension cable as they seem to be the best available but didn't want to spend money on something I won't use more than a few times. My Dad said he had an extension cable with a thicker lead for me to use but then forgot to get it for me so just said that i can use the one that's already there, I was a bit wary about this especially as it's probably over 10 metres long! Anyway I turned the car down to 6 amps and it worked fine without anything feeling warm, also tried it at 8 amps and this was also fine. So I'm not saying it's a good idea but if you're desperate and keep checking for overheating etc a granny lead should be OK. Better if you can avoid using an extension cable of course!

Main practical issue that I found like others have said is that you can't get much range overnight, especially if limiting the current to avoid overheating, even having it plugged in for 12+ hours a day I struggled.

Ericmark - loss of PEN wasn't something that I had considered, I'll certainly be more careful in the future! I even had it parked on the street in front of the house! I was also with British Gas on that same tariff, still with them now (7.9 p at night for 5 hours), just wondering what your logic was for switching to Octopus? In my case I'm definitely making a saving with the low night rate but guess it depends very much on mileage and how much your house is using during the day etc.

I just "take the hit" if I'm away on a long trip and I use public fast chargers. I did 560 miles in the EV on Monday (Cumbria to Northamptonshire and back). I probably cost me about £10-£20 more than it would have done in my last diesel car, but it's rare that I'm doing trips that are so long. On balance, I still save about £100 a month on fuel - not that it's a fair comparison, as the EV has about 3x the power of my last diesel!

 

[Mottie]

I was also with British Gas on that same tariff, still with them now (7.9 p at night for 5 hours), just wondering what your logic was for switching to Octopus? In my case I'm definitely making a saving with the low night rate but guess it depends very much on mileage and how much your house is using during the day etc.

We've just ordered a hybrid today - was considering a plug-in but decided it wasn’t worth it for the use we will give it but we are with OVO and they do a special rate of 7p at anytime. It needs syncing up with either a proper charger or an app if you are using a granny lead and your car has to have an internet connection to meter the electricity used. Apparently it goes through a third party - you pay the regular price for electric and at the end of the month, they work out what you have used for the EV and send a credit to your account. Might be worth your while looking at it in case it is suitable for you and your car.

 

[ericmark]

just wondering what your logic was for switching to Octopus?

If you quote, or use @gmc600 in your case, you get notified someone is talking about what you have said, so I have missed your question.

So all down to solar panels, I was with British Gas and after 18 months still not being paid for export, they said the application was in the wrong format, but used their forms, and I would get back pay once sorted, I was locked in for a year, with a £75 fee if I left early, asked my solar installer for help, and they said they had also had problems with British Gas and Scottish power, both use paper applications, and Octopus was in comparison easy to get up and running. (May have been because they get £50 to get me to move.)

So waited until contract had run out, then changed to Octopus, they told me the problem was a lack of an MPAN number, seems I need two, one for import and one for export, told my installer, and within two weeks all sorted and being paid for export, they can't pay for export without that number, so British Gas could have never back paid the money for export.

May £73, June £77, July £65, August £58, Sept £12.50 to date for export, that is a lot of money I was losing with British Gas. Basic means in summer electric is free. What I get paid is more than the bill including standing charge.

The EV rate of both British Gas and Octopus very similar when you have not given them control. Son is with Octopus he pays far less to me, as car and charger installed by Octopus, it does mean electricians can't compete with Octopus, the same happened with Worcester Bosch boilers, the plumbers could not compete, parts cost more than they charged for whole job.

Think his off-peak around 6p/kWh.