UKH

I have a plug-in hybrid car, which seems to need 10kw for a full charge, and charges in about 5 hours at about 2kw/h.  I use Octopus Go with cheap units 00:30 to 04:30 so it will mostly charge on cheap units if I haven’t emptied the battery.  I’m using a 3-pin 13A domestic plug charger (sometimes known as a ‘granny charger’).  I know granny chargers are not a long term solution.  But for the moment it’s a workable solution.

I am looking to get a home EV charger, for a quicker charge, and maybe get Octopus’ “Intelligent” tariff.  The costs of getting and installing a home EV charger have to make sense.  I’ve hit a problem in that my house has (unfortunately) an 80A supply (not the usual 100A supply) and I’m on a loop with a neighbour.  

I am learning that EV chargers require permission from the distributor (in my case Electricity North West, ENWL).

A local EV installer has looked at my 80A supply, the loop, my consumer unit and started using lots of long words like diversity and load balancing, and quite large amounts of money. The installer has proposed a solution with load balancing and diversity to ENWL but this doesn’t seem to have been satisfactory.

ENWL also recommend upgrading the supply which will mean (someone, probably me) paying for a trench from the road to my house and the neighbours with cost and disruption, which isn’t swinging the cost equation in favour of a home EV charger.

Apparently, there are 7.2kw EV chargers that you can reduce the supply to 3.6kw, but still no joy with ENWL.  Nor the fact that I have a 10kw electric shower, and oven etc which would be far more than the EV charger, but no joy there either.  Rules are rules ....

I’ve read about something in the car's manual called a Green’up socket which seems to charge at 16A, instead of the 10A granny charger, but I’m told they aren’t available any more.

I suppose I’m looking for a plug that will give a bit more than 2.3kw/h, but won’t incur the requirement to apply to ENWL. But maybe I’m quite out of luck in that respect.

Does anyone have any innovative suggestions, or been in this position?

TIA

In reply to yorkshire_lad2:

Keep using the granny charger (get one with a timer if you haven’t already or the car doesn’t do that for you). For a 10kwh hybrid it’s not worth anything else. You can easily charge it overnight, mostly at cheap rate. If you are slightly short of change you have a petrol engine anyway. What does ‘not a long term solution’ mean anyway? I used one for 4 yrs until I got a full EV. 

In reply to yorkshire_lad2:

Does it need to be legal? 😏 Cos if you're not bothered about regs it's easy enough. 

As you correctly suppose, a 16A or even 32A charger running between 00:30 and 04:30 is very unlikely to cause a problem, as there will be very little else using power at this time. Unless you or your neighbour have night storage heaters?

I believe there are EVSE systems that can monitor the total load on your house supply and reduce the charge rate if it gets too high. It might be worth checking if one of these would comply with regs?

In reply to minimike:

Thanks for the reply.  That's pretty much my thinking (and the car does the timed start).  But I'm trying to find out of there's an alternative that doesn't require an application to the distributor and that doesn't involve substantial cost and upheaval. "not a long term solution" meant that much of what I read says it's not ideal using a granny charger pulling that amount of power over that period of time through a domestic 13a socket as there is a risk of the socket wearing out, burning out etc etc.  It's a 10A charger on a 13a plug so should be OK.  There are stories on the web of people having issues with sockets, but there are also stories on the web of people using them quite happily.

In reply to Hooo:

Thanks for the reply

It had crossed my mind, and it would seem there are quite a number that are installed and haven't been cleared by the distributer.  And if there's an issue locally and it's found to be down to my EV charger, having been told once that it's not satisfactor, it might just piss off an official somewhere, and I don't really want to upset my neighbours either.  Nice idea about the EVSE systems that might monitor total load: I'll look into that.Thanks.

In reply to yorkshire_lad2:

Get a sparky to install a high quality (MK?) IP rated external socket and make sure it’s on a 32A rated separate circuit. Then you can be confident in using the granny charger forever. If you’re currently (Thankyou!) running it out the window from a cheap plastic socket with a crack in it I’d probably stop that sooner than later..

In reply to yorkshire_lad2:

Our house was on a shared line with another - meaning there was insufficient load for an EV charger and hot tub and heat pump - national grid sorted for free.

In reply to minimike:

Oh and don’t use an extension cable reel.. whatever you do. Please.

In reply to yorkshire_lad2:

Loading balancing only really matters if you were charging during the day and decided to run the oven and multiple other higher power items at the same time, it would reduce the power used by the car charger. This is something you could manage yourself quite easily. 

In reply to minimike:

That’s what we did with a blue commando socket.  Should have a DC sensitive RCD or RCBO in the distribution board for current regs I think. 

I have a third party charger from “zencar” which can be set to 8A, 10A, 12A and 16A.  The 8A was handy when we turned up at an elderly relatives to find the socket they said we could use was an old round-pin one with a modern adapter…  Added bonus was buying it with a long and brightly coloured lead.

A 2.5mm^2 blue commando extension lead is fine, just don’t leave it wound on a bobbin etc!

In reply to yorkshire_lad2:

As several have said, the quick solution is to get a sparky to install an outside socket on a dedicated circuit and just keep using your granny charger.  I've done this for eight years with two different EVs. 

The only problem I had was a manufacturing fault with the charger cable itself.  For peace of mind, as well as making sure there's a suitable circuit breaker as per Wintertree's post, put a smoke detector in your consumer unit cupboard.

By the way - kilowatts are a rate of energy transfer, and kilowatt-hours are a total amount of energy.  So in your cheap period you're getting 2.2kW for 4 hours, to deliver 8.8kWh.

In reply to yorkshire_lad2:

Can you get a petrol generator and just drive around with it in the boot for a handy, charge anywhere solution?

In reply to yorkshire_lad2:

When an electrical engineer explained "diversity factor" to me in ration to loads on a transformer I was like "really, a fudge factor"? 

Basically, my understanding is that it's a reduction factor applies to each load of they're unlikely to operate at the same time. (so that you can have multiple circuits whose loads add up to more than the supply rating.

As others have said, just get a spark to put on a 32a auxiliary circuit on, with a 3pin round plug. And don't have a shower at the same time. 

In reply to Jamie Wakeham:

And Jamie wins (loses?) the who’s first to correct the units game! 

In reply to yorkshire_lad2:

I've granny charged my EV for years. I had a plug I fitted let the smoke out but I had hacked it after a mishap with the factory charge lead and a heavy roller shutter. The factory one was crimped (a screw backed out over time in my replacement) and the factory one had a thermistor fitted for fault detection. Bulletproof.

Jk

In reply to minimike:

This is why I was asking if it needed to be legal. Installing a 13A (or 32A ) socket will work fine and I assume won't be subject to the checks that the OP is having trouble with. But it's not strictly legal. If you are installing the socket for the purpose of charging a car, then the regulations say it needs to be treated as if it's an EVSE installation. If you lie and say that it's for something else you will almost certainly get away with it, but it's not legal.

In reply to wintertree:

I run an Ohme EVSE from a 32A commando socket. The DC RCD part is built into the Ohme, so just a regular RCD needed in the CU.

One thing you should have is PME fault detection. This probably won't be built into a plug in EVSE. This is one of the reasons that routine use of a granny charger is frowned upon.

In reply to Hooo:

And if it’s already there and you just happen to plug an EV into it.. is that illegal too?

In reply to minimike:

No, that's fine. It sounds silly, but thems the rules.

They've made this rule specifically to stop people doing what you suggested - getting around the regulations on installing an EVSE by just installing an outside socket.

In reply to wintertree:

More of that sort of thing!

There's a person who parks their Tesla on the road near me (it's terraced housing here, so driveways are rare) and they run a black lead from the house to the car across the pavement, which is pretty antisocial - a colourful cable would be nice in that case (admittedly, they also park on a double yellow to get that close to the house, so there's probably no hope for them, but I have hopes other people might do things better!)

In reply to minimike:

I'm a physics tutor.  Can't help myself...

In reply to Hooo:

The Zappi charger from Myenergi can adjust the charge rate depending on the total load.

In reply to yorkshire_lad2:

There's a reason why you have an 80A fuse in you cut-out - the cable feeding you and your neighbour probably isn't large enough to give you both 100A. Irrespective of the fact neither of you may ever draw 100A. That, and perhaps your ELI reading is too high and the DNO has reduced the size of you cut-out fuse to overcome that. 

I've said this on here before, and I normally get shouted down when I do, but the Electricity distribution network, as it stands, won't cope with the extra demand expected of it. Lots of the network is old and the cables and wires are small and were put in when houses were first electrified. We can't expect a cable installed back in the 40s-50s-60s to be able to cope with the loads we are now seeing today. 10kw showers, Induction hobs, fast car chargers. Potentially all on at the same time, X2 if your neighbour has the same if you're looped. Your supply cable is going to burn out. 

How many semi detached houses are there that share a supply ?? Possibly the cut-out is under the stairs, in the middle of the house. A complete nightmare to put both houses on their own feed.

In reply to arch:

That's a point worth thinking about, but in no way does it need to be a show stopper.

We do about 10k miles a year, which I believe is about average. That's about 2500kwh PA. With a 7kw charger that's about 7 hours charging a week. All done at cheap rate when no one else is using anything. So with a bit of organisation there is no reason why two average households sharing a 60A supply couldn't both run an EV. Sure, they couldn't just plug in and charge whenever they wanted, but they could make it work.

Many thanks for all the comments, ideas, information and suggestions.  Very helpful and enlightening.

In reply to arch:

Birderline trivial to run a new, parallel feed to a pair of external meter + distribution boxes for BEV chargers and ASHPs however?  This solves the problem without having to put separate feeds in for each house.  Legislation to make the electricity firms only charge one standing charge despite two meters where this is judged the proportionate way forwards.

Then probably not so bad to run some chunky cables from the new meter boxes to the inside DBs, lift a couple of carpets and route out a channel in the concrete floor or run it through the floor void (as appropriate) to take the houses back to one meter each…  Only really has to happen for one house with an updated cable and can be left until there’s major refraction planned….

In reply to yorkshire_lad2:

According to whom?

In reply to yorkshire_lad2:

I have a Zappi/Myenergi charger on Octopus Go. We also have an 80A-to-house supply and that hasn't been a problem for the smart meter or the Zappi - 80A is a lot mind!

Octopus Go is great though. You don't have to do anything once it is set up. Just plug in your car and it will automatically charge overnight at 7.5p/kWh (instead of 25.26p - so about 1/4 the rate). You can boost it during the day if you need to.

You can also delay your dishwasher and washing machine to use the 2am to 6am slot at the same rate. The car itself appears to charge at random times between 11pm and 8am (at cheap rate) since I think Octopus use the cars to balance the grid.

Alan

In reply to wintertree:

Redecoration, not refraction…

In reply to arch:

I am interested in your comments here. I can see that induction hobs, car chargers and heat pumps will take increasing amounts and 10kW showers have been around for years. In many other areas though we are cutting back with electric fires, fan heaters disappearing and light bulbs a fraction of what they were. 

Is the problem that the old cables don't have the capacity - 80A is huge! - or is it just that they are old?

Alan

In reply to arch:

Perhaps the reason you are getting "shouted down" is that what you have said is an easily quantifiable and testable statement - "Your supply cable cannot cope with a load of X Watts" - without any reference to your source. Is this a "gut feeling"? You don't need gut feelings when you have physics.

In reply to Alan James - Rockfax:

Two car chargers is 64A nominal, which is most of 80. Doesn’t leave much for showers and general use.

In reply to Jamie Wakeham:

I suppose the kWh is a "practical" unit of energy, but it's pretty horrible, being a kJ (a unit of energy already) divided by one time unit (sec; metric, hurray) multiplied by another (hours). Ugh. Why don't we use MJ (1 kWh = 3.6 MJ).

In reply to John Stainforth:

As an ex rower I prefer teraergs. 

In reply to John Stainforth:

Because meters would need to be a 1000 times wider to fit all the digits in.

In reply to Maggot:

No. My new smart meter displays whole kilowatt-hours. At my current usage, it will roll over to 00000kWh in about 600 years. If instead it showed megajoules, it would roll over from 99999MJ to 00000MJ in about 170 years. That’s plenty enough for me!

Cheers

Al

In reply to John Stainforth:

I have to agree that kWh is a horrible unit and MJ is much nicer. But, it does make sense if you're charging a car. If you need to add 25kWh and it's charging at 50kW then even the most mathematically illiterate person can work out that they have half an hour to kill. If they need to add 90MJ at 50kW, it's not so obvious.

In reply to Hooo:

It makes sense if you're using any kind of appliance really.  Energy being priced by the kWh means you know immediately how much it'll cost to run a 1kW appliance for an hour.

I don't see how it's 'horrible' personally, it's just based on the Watt hour instead of the Watt second (aka Joule).  It's the same as measuring speed in kph instead of m/s - choosing both units to suit the 'scale' of the thing being measured ie: kW instead of W and hours instead of seconds. 

It's only horrible in the sense that time is that little bit of the Metric system that isn't decimal.  (If an hour was one kilosecond, then a kWh and a MJ would be the same thing.)

In reply to deepsoup:

For goodness sake, I pay for my electricity in kWh, so I am utterly familar with that. (Too familiar!)

From a scientific point of view, the redundant thing about the kWh is it is an energy unit divided by a time unit multiplied by another time unit to come back to an energy unit. What makes it nasty is the use of two different time units (one metric, the other not) to make this mathematical somersault. 

Your analogy with speed is not a good one, since both kph and m/s are distance per time (although the former is mixed metric and non-metric). A closer analogy with speed would be to use metres per second hours for distances, instead of metres!

I don't understand your comment about the second being a part of the Metric system that is not decimal. Milliseconds, microseconds, nanoseconds, Gigaseconds, etc are used all the time in science and engineering.

In reply to John Stainforth:

It doesn't especially matter that you are, what's important is that everybody else is too!

That's pure semantics.  The Watt and the Joule are both derived units.  It's just your habit to think of a Watt as a Joule per second, but that's no more scientifically valid than thinking of a Joule as a Watt second.  (And then your problem disappears - kWh and J are both just a unit of power multiplied by a unit of time.)

I didn't say the second isn't decimal, I said time isn't.  The second is the SI unit of time, but minutes, hours, days and years are all also used all the time in science and engineering.  Quite a few other non-SI units are too.
eg: kph, rpm, lightyears.

In reply to planetmarshall:

35 years working in the electricity distribution industry. The DNO i work for spending millions of pounds to unloop shared services because they  don't

have the capacity as they stand.