EV Charger Cost.

Jenni_D

MeteredOut said:

Jenni_D said:

14.4kWh is likely the battery max capacity, not the usable capacity. And it won't likely charge at 3kW ... there'll be losses involved, plus the fact that a UK 3-pin charger will charge at a max of 10A, so nearer 2.3kW; reckon on 2.0kW at best. (Not that this affects the total power delivered, just that it takes longer to get there).

And there's no way a Kuga PHEV will get 3.5 miles/kWh - not with having to lump around the ICE equipment as well as the battery and motor. 3 mpkWh is probably the best you'll see, and lower still in winter.

My 3 pin charger can charge up to 13A. On the rare occasion I'll let it run at 12A, but generally keep it at 10A.

Anything connected to a ring main socket is only rated for 10A continuous ... it's only if you have an EV-rated socket on a separate spur (with suitable MCB and RCD) that you can go higher than 10A continuous. 🤷‍♀️

facade

born_again said:

WhatAHoot said:

I thought I’d add a real-world data point to this, as charger costs can sound a lot scarier than they actually are in practice.

I’ve got a 2023 Ford Kuga PHEV with the 14.4 kWh battery. Despite the battery size, the car’s max AC input is only around 3 kW, so there’s no benefit to an expensive wallbox for me. I charge using a standard 3-pin 13 amp charger on a dedicated outdoor socket with RCD protection, which is perfectly adequate for overnight charging (The electrician also future proofed with larger cable for a wallbox incase I switched vehicles)

On Octopus Energy’s EV tariff (8.5p per kWh between 00:30 and 05:30), a full charge costs roughly £1.20–£1.30. From empty to full takes about 4 hours 45 minutes at ~3 kW, which fits comfortably inside the cheap-rate window.

To sanity-check the numbers, I built a small EV charging calculator on SPAM  website, under Resources in the navigation menu

Using my setup as an example:
Battery: 14.4 kWh
Charge rate: 3 kW
Tariff: 8.5p/kWh
Cost from 0–100%: ~£1.22
Cost per mile: ~0.3p (assuming ~3.5 miles per kWh)

For PHEVs especially, a wallbox often isn’t financially justified unless you want convenience or future-proofing. A safe, properly installed 3-pin socket plus a cheap overnight tariff can be more than enough and keeps upfront costs very low.

3 posts all with one website mentioned. 

Chips & beans anyone?

Well spotted, I only spot hyperlinks.

It isn't much of an advert though, if the calculator site reckons 8.5p per kWh divided by 3.5 miles is 0.3p a mile!

(I just assumed that he meant around 3p a mile, which would be reasonable in the Summer on that tariff, and for once I refrained from showing off my maths skills ).

I can't be bothered with the maths, but I can't imagine that only taking 70 ish kWh per week @ 8.5p could offset the increased cost of standard rate electricity for running the rest of the house on. It certainly isn't worth me switching to an EV tariff with my current mileage and I have a 40kWh ish BEV.

MeteredOut

Jenni_D said:

MeteredOut said:

Jenni_D said:

14.4kWh is likely the battery max capacity, not the usable capacity. And it won't likely charge at 3kW ... there'll be losses involved, plus the fact that a UK 3-pin charger will charge at a max of 10A, so nearer 2.3kW; reckon on 2.0kW at best. (Not that this affects the total power delivered, just that it takes longer to get there).

And there's no way a Kuga PHEV will get 3.5 miles/kWh - not with having to lump around the ICE equipment as well as the battery and motor. 3 mpkWh is probably the best you'll see, and lower still in winter.

My 3 pin charger can charge up to 13A. On the rare occasion I'll let it run at 12A, but generally keep it at 10A.

Anything connected to a ring main socket is only rated for 10A continuous ... it's only if you have an EV-rated socket on a separate spur (with suitable MCB and RCD) that you can go higher than 10A continuous. 🤷‍♀️

I know, which is why I rarely go above 10A. But you said a UK 3-pin charger will charge at a max on 10A, which was incorrect. I don't have an EV rated socket - its a standard 13A externally wall mounted socket.

Jenni_D

So you do breach the BS regulations then ... BS1363 ... if you allow your "granny" charger to exceed 10A continuous. A UK-specified "granny" charger should not exceed 10A at any time if used on a ring main socket. So no, I'm not incorrect. 🤦‍♀️

WellKnownSid

Jenni_D said:

So you do breach the BS regulations then ... BS1363 ... if you allow your "granny" charger to exceed 10A continuous. A UK-specified "granny" charger should not exceed 10A at any time if used on a ring main socket. So no, I'm not incorrect. 🤦‍♀️

"A breach of the BS1363 regulations"?  I think you are conflating multiple SRs, NSRs and standards.

But broadly you are correct.  Many decades ago, shortly after graduating, I built test rigs for 1363 which ran at 14A for 8 hours against a maximum 52 degree C delta T - this was only possible with a modified plug without a fuse fitted.  A 13A BS1362 fuse will happily take 14A for decades but will generate loads of heat (I^2.R).  IIRC the actual safe continuous rating for a typical switched BS1363 socket - derated through use - is only about 8A.