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Thinking of going Electric? Some things to think about…

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X5Sport
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Thinking of going Electric? Some things to think about…

Post by X5Sport » Mon Apr 11, 2022 8:36 pm

So I’ve ordered an EV. What else do I need to think about?

As I’m now in that position I though I would start a thread to illustrate to others the things that need thinking about as you also make the switch from fossil fuel to electron power.

Vehicle range

As was the case with ICE powered cars, there is a difference between the official WLTP tested range and the actual range you will find when you start using yours.

I have ordered an i4 M50 which has a theoretical range of 316 miles. That is of course under ideal conditions and from what I’ve read or seen to date will never be achieved. Taking 50 miles off the published figures is a reasonable assumption, with more off in winter unless you pre-condition your car whilst it’s still connected to a charge point. Pre-conditioning means running the heating, ventilation and if fitted, battery heater system. Doing this whilst not connected will reduce your range somewhat!

The load of the car and any external kit like bike racks or a roof box will also have a range impact.

Many EVs have a towing limit well below what you might think. The iX3 as an example can only tow 750kgs regardless of the trailer being braked or unbraked. The i4 can only tow 1.4T, still better than the iX3 but down on an ICE powered car.

Range anxiety is something any EV owner going on long journeys will suffer from to some extent. Plan your stopping points before you get to 20% battery capacity. That gives you a short reserve to get to another nearby point if your intended target is closed or broken (this issue is being addressed by the Government who are now insisting on a 99% availability for commercial charge point operators).

Vehicle charging is also worth checking. Some owners have been caught out by their vehicle only having a 3.6kW charging rate. Fine for a small battery but not much good for a work van needed every morning.

Battery Life

Recent testing indicates that the average EV battery will be good for around 200,000 miles (some will be more). This assumes that you keep the battery state between 20% and 80% and you use slower charging rates. It is possible to charge at very rapid rates. My i4 can charge at 205kW DC from 20-80% in just 30 minutes, however that heats the battery and should not be done regularly. Similarly fast charging to above 80% isn’t good for the battery. This is down to heating so many rapid or super chargers will ramp down the charge rate as soon as 80% capacity is reached so as to keep the heating down. Super chargers can also be expensive to use, some as much as a tank of petrol/diesel.

It is also recommended that you keep the battery between 20 and 80% and don’t recharge every day unless your range requirement needs it. Battery life is all about ‘cycles’ and each time you charge is one ‘cycle’ less. Running the battery down to around 20% before recharging is suggested as a ‘good thing’.

EDIT: Storage: the i4 manual states that as long as the battery is charged to 50% it can be left for about 6 months unused before needing charging. BMW recommend monthly checks (as they do for their ICE cars). A similar performance could well apply to other EVs as well.

EDIT 13/04/22 - Battery & Charger Calculations (the boring bit!)

All EV batteries are rated in Kilowatt Hours (kW/h). This is different from standard ICE batteries that are rated in Ampere Hours (Ah). Don’t confuse the two.

In the UK we are billed for electricity by the kWh - which is handy because it makes some of the calculations easier. 1 kWh = 1 unit of electricity at your tariff rate.

Fortunately all charging points are also rated in kWh (unusually helpful of everyone innit :D ).

As an example: taking the i4 battery at 81.7kWh usable (it’s an 84kWh battery but you can’t use all of it as is the truth for any battery).
Single-phase domestic supply can feed a maximum of 7.4kWh. So the maths is straightforward.

To charge that battery from dead in theory needs 81.7 ‘units’ of electricity at your going rate - mine was 20p/unit = £16.34.
In reality you’ll never charge from dead so the cost should be lower (in theory….but - and I’ll cover the ‘but’ lower down in this section) and it also depends upon your local tariff which might have a cheap rate between say 00:00 and 05:00 of just 5p, so meaning a full charge is under £5.

The time taken is capacity divided by delivery rate of the charge point (81.7/7.4) = around 11 hours.

Commercial chargers could be anywhere between 7.4kWh and 350kWh. Costs anywhere from free to a lot. The highest charge I’ve found so far is in parts of Wales where one operator charges £1-10p per unit (IMHO that’s excessive). Typical costs are between 25p and 65p/unit.

The ‘but’ bit…..your charge point is just a mains voltage connection to the car, it doesn’t act as a charger. EVs have a built in AC to DC charger as batteries are DC. These on board AC chargers are rated anywhere between 3.6 and 11kWh typically. As with any battery charger there are losses in the system as nothing is 100% efficient. You will not get 7.4kWh of DC out for 7.4kWh AC in. Typical efficiency is about 85%. Some are better and some much worse. When looking to buy an EV it’s well worth asking the salesperson. VW & BMW are above >90% for theirs and modern ones are generally better than those from a few years ago.

Anything over 22kWh is likely to be a DC charge point and those connect directly to the battery via the Type 3 connector fitted to the car. For the i4 it can take a maximum of 205kWh DC in meaning it will charge the battery from dead in just over 30 mins. All high speed and ultrafast chargers reduce their delivery rate once the battery hits 80% capacity in order to prevent overheating.

Cost of one of these charges is about £25 with the BMW discount. Still much cheaper than ICE even taking the range reduction (240 miles instead of 400 miles with say an E71).

If paying the amount the Welsh supplier charges then that cost rises to £90, or about the price of half a tank of diesel at present, for half the range. Not so good so it pays to know your charge costs on route. It’s a lot harder than just rocking up at a fuel station with 18 pumps too.

Charging points

You’ve be wanting a home charging point installed to top up your battery too. There are things to note here too.

Charging from a 13A socket (@2.4kWh) is possible but VERY slow. As an example, my i4 will charge in about 8.5 hours at 7.4kWh (Mode 3) but it takes 32 hours on a 13A connection (Mode 2). And that’s 32 hours of effectively running a kettle continuously. Not something to be done except in an emergency.

Single phase homes can only charge at a maximum of 7.4kWh (32A), to go to 11kW you need a three-phase supply. Most houses do not have 3-phase and converting is VERY expensive.

Firstly, can your dwelling cope? Many older properties only have a 63A main supply fuse and a modern EV such as a Tesla, BMW i, Polestar etc have an on board 11kWh mains powered charger that will draw 7.4kWh (it’s limited to that by the charge point) from the domestic supply. That’s 32A or 50% of you main fuse rated limit. Turn in your electric oven, tumble drier and washing machine and the main fuse will blow!

If you have a 63A circuit then you should get it upgraded to a main feed of 100A. You energy supplier should not charge you to do this. That ‘uplift’ may well also mean the tails between your meter and fuse board (Consumer Unit) will also need upgrading. You will be charged for that by your electrician. 63A is fine for a car that can only charge at 3.6kWh, or you can limit the EV charge point so that it only draws 3.6kWh. That will extend your charging time.

Talking of meters, you really need smart metering set to 30 minute reading intervals in order to get cheaper rates such as between midnight and 04:00 (Some are 00:30 to 04:30). Cheap rate power varies between £0.05 to £0.10 per kWh off-peak and a lot more than that on peak. Economy 7 is an alternative. You should also look at EV specific tariffs though at the time of writing this (Apr ‘22) changing tariffs is not recommended at the moment due to market fluctuations.

If your consumer unit (CU) is based on fuses then you either need a separate CU with circuit breakers for the EV point, or upgrade your entire system to circuit breakers. This can be expensive. You will ideally now need as many as 5 spare (was 3) (EDITED 22/4/22) ‘slots’ in your MCB based CU (Surge protect, new RCD, 32A or 40A MCB for the EV charge point. Your installer may well need to shuffle things around in your CU to give house circuits and car circuit electrical separation so nothing that happens on the EV side affects the house side (usually only the RCDs are affected.

A typical full install of a charge point (including cabling) will be if the order of £1100 as a baseline. That could be for between 10 & 15 metres of cabling between the CU and charge point. Many of those installs only cover the basics and consideration should be given to improving the quality be adding electrical safety.

Such improvements are for a changed RCD as (if like mine) yours is AC only then it won’t detect a DC ‘leak’ from the car and trip. Putting DC onto the house side is a bad thing! So you’ll need a new RCD that can detect AC & DC issues. You should also consider having some form of surge protection installed in your CU. You’ve just bought a very expensive EV so you don’t want a local power surge knackering the car as you can bet it won’t be covered by the warranty!

EDIT 22/04/2022 - changes to the electricity supply and installation regulations at the start of April 2022 mean that the previously ‘recommended’ Surge Protection device is now mandatory for all new installations. This will inevitably now mean that a second CU will need to be installed. The surge protection prevent spikes getting from the supply to your expensive EV. The second CU could (and in my case did) mean that the EV circuitry is now completely separate from the house side electrics. The electrician may well add a new pair of tails from your meter to this second CU. In my view this electrical separation is a good idea. <End Edit.

External cabling should be SWA armoured. If your chosen charge point has mains supply load monitoring then you’ll need an Ethernet or data pair as well. This can now be done with a single cable containing both power and data signalling cores. Saves having 2 SWA cables laid in.

To take advantage of cheap electricity you need a ‘smart charger’. These come with either and/or Ethernet, GPRS (3G) and WiFi. Some now have 4G. Note that 3G will start to be shut down by the cellular operators from 2025 as they need the radio channels for 5G.

All of this will very likely mean your EV charge point cost rises to around £2k - unless you have a tame sparky who will let you run the cables and just do the connections for you or you are NIC EIC approved.

Solar cells

Some EV charge points can work with dwellings equipped with solar cells and will take advantage of the exported capacity by diverting it to your EV instead of the grid. Not all smart chargers can do this so check the spec carefully. The more expensive ones tend to include solar (or wind) generation integration but the cheaper ones don’t. Of course if you aren’t there in daylight, or the wind is calm then you’re out of luck.

From what I’ve read so far, many (could be most?) solar installations are just 4kWh. You could have more if your roof permits it, and there may be local electricity company limits too. One of my colleagues is installing a 15kWh array but his electricity company have refused to allow that much to be connected to the grid. He can charge his 2 EVs though.

Charging time rule of thumb

Depends upon the charge rate and battery type.

For my i4, (84kW/h battery (81.7 kW/h net usable) a charge rate of 7kWh adds about 25 miles/hour of charge. 7.4kWh is around 30 miles/hour of charge. A 13A (2.4kWh) connected charge is about 5 miles/hour of charge….so you’ll be there a while!

Servicing
Service costs should be about 30% less than for an ICE vehicle (no oil, filters, fuel filter, engine air filter etc etc) but you do need to bear in mind that your local Indy may not be able to work on much other than brakes or the cabin filter. This is because EVs use high voltage batteries. The i4, iX, iX3 use 400V main power. Getting your fingers in the wrong place can be fatal! My dealer has special carbon fibre devices to pull anyone away from a vehicle in the event of an accident. Technicians have been seriously injured (not at my dealer) or worse. DIY is something to be thought through carefully. Drilling a hole in the wrong place might have unintended and unfortunate consequences!

The next generation EVs could have 600V or 800V main batteries (both are in development). Higher voltages - less power drawn so range increases (or greater load capacity for the same range).


I’ll add more things as I experience them.
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Thinking of going Electric? Some things to think about…

Post by sapphireblack » Mon Apr 11, 2022 10:42 pm

I'm not a numericist nor am I interested in an EV but that bunch of figures, (skim read) makes it all seem very hard work to save the planet.

Perhaps a great idea in principal but would seem to not have been developed enough to be a truly viable alternative yet. Not by a long way in fact :roll:

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Thinking of going Electric? Some things to think about…

Post by Leslie » Tue Apr 12, 2022 12:01 am

That's a good writeup , 32 amp for 10hrs straight is a lot of juice, think of it as running your electric shower all day :D the national grid will love it , time to buy electricity shares :driving:

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Thinking of going Electric? Some things to think about…

Post by StuBeeDoo » Tue Apr 12, 2022 6:49 am

I echo Leslie's sentiment that it's a good write-up, X5Sport. :thumbsup: Wor Lass keeps mentioning replacing her car with an EV. I can't make her understand that our electricity bill will increase dramatically - potentially by more than she currently spends on diesel.

I had an electrician around to discuss putting in a charging point and he quoted me £1600 as a baseline, but ".....that could easily double". Our property is a 1903-built mid-terrace former quarryman's cottage, with a detached garage to the rear and the electricity supply (and CU) at the front - and we're on a looped supply. Nothing is impossible, but it's not going to be straightforward, and fitting all the EV charging infrastructure will probably involve some interior re-modelling and certainly some re-decoration of rooms that were done less than a year ago.

Then add-in that she's one of these people who insists that everything except the fridge and freezer are turned-off at night, so she's unlikely to want the EV charging overnight. :(

"Range anxiety" shouldn't be too much of a problem. The furthest she is likely to go is less than 200 miles from home but she would still need to know she can re-charge before returning home.

I'll keep my eye on developments in the sphere of EVs, but as long as I can keep her in an ICE-propelled vehicle I will.. .........And at our time of life I doubt we will ever go electric. If I last that long, I will be giving-up driving within 15 years.
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Thinking of going Electric? Some things to think about…

Post by Wayfarer » Tue Apr 12, 2022 7:12 am

Leslie wrote: Tue Apr 12, 2022 12:01 am That's a good writeup , 32 amp for 10hrs straight is a lot of juice, think of it as running your electric shower all day :D the national grid will love it , time to buy electricity shares :driving:
A great write up, any idea what is the battery loss rate is when the car is not being used, as at present my mileage is fairly low and I don’t think the investment would stack up, hybrid maybe in a few years, but currently planning on stay with oil based fuels for transport until the plan is properly developed, as I suspect and hope Hydrogen or similar will make an appearance and it could well be a Betamax vs VHS moment for those who remember.

Cost wise it’s great if you have a large solar array, and live in a house with its own driveway, otherwise that’s £22 at current default rates, probably going to be nearer to £33 after October unless you can get on one of the current cheaper tariffs that will disappear as the demand mops up the surplus electricity, or with street parking you’ll have to rely on public charging points.

The plan would be great if the infrastructure was there to cope with the additional demand but it isn’t and in my view, the cost of upgrading the grid to cope with this latest foible will be astronomical not to mention the time it will take, but I suppose that will fit in with the time scale to plan and build the new nuclear reactors!
But the additional money the government needs for this will no doubt be added to the electricity costs and motoring costs to more than cover it.
And that’s before everyone is forced to install heat pumps!

But enjoy your new car, a neighbours daughter and her family have just bought an ix3 and are very pleased with it so far, so maybe it is the future and maybe I am just being a pessimist.

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Thinking of going Electric? Some things to think about…

Post by StuBeeDoo » Tue Apr 12, 2022 8:39 am

StuBeeDoo wrote: Tue Apr 12, 2022 6:49 amI'll keep my eye on developments in the sphere of EVs, but as long as I can keep her in an ICE-propelled vehicle I will.. .........And at our time of life I doubt we will ever go electric. If I last that long, I will be giving-up driving within 15 years.
............ And she's already questioning whether she will even need her own car once her aging parents depart this mortal coil.

In terms of cost, it's not that we can't afford the outlay, more like we won't see much of a return on the investment.
Last edited by StuBeeDoo on Wed Apr 13, 2022 6:17 am, edited 1 time in total.
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Thinking of going Electric? Some things to think about…

Post by X5Sport » Tue Apr 12, 2022 9:51 am

Wayfarer wrote: Tue Apr 12, 2022 7:12 am
A great write up, any idea what is the battery loss rate is when the car is not being used, as at present my mileage is fairly low and I don’t think the investment would stack up, hybrid maybe in a few years, but currently planning on stay with oil based fuels for transport until the plan is properly developed, as I suspect and hope Hydrogen or similar will make an appearance and it could well be a Betamax vs VHS moment for those who remember.
According to the Owners Manual for the i4, as long as the battery is charged to at least 50% you can leave it ‘stored’ for up to six months before it needs recharging.

With regards to recharging costs, the i4 is approx £15 for a full charge on domestic supplies. A lot depends upon your tariff. There are also an increasing number of supermarkets where you can plug’n’shop and the charging is free. Some employers also provide charging at no cost - it’s a current government policy that ‘encourages’ them to do so. My employer is part of the scheme and expects to have about 200 chargers on site over the next few years. They’re currently only 7.4kW units but that is a full charge once per week.

I’m using approx £200/month on diesel so four or five ‘tanks’ of electric (range assumes 240 miles ‘per tank’) is significantly cheaper. Of course the increased costs of energy will bite but that’s an unknown. Diesel is going to get more expensive because there’s more demand for (currently) less availability.

…..and I remember the Betamax/VHS wars of the 80’s. The UK developed Video 2000 which was by far the best but as usual two years too late to market.
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Thinking of going Electric? Some things to think about…

Post by X5Sport » Tue Apr 12, 2022 10:33 am

StuBeeDoo wrote: Tue Apr 12, 2022 6:49 am
Then add-in that she's one of these people who insists that everything except the fridge and freezer are turned-off at night, so she's unlikely to want the EV charging overnight. :(
She won’t want to do that as turning the charger off will lose the configuration. All of the chargers I’ve considered have safety devices within that ‘kill’ the power in a fault condition. They’re now legally required to have such circuitry to be sold in the UK. You could try convincing her that if it does catch fire, it’s outside….. :P
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Post by Leslie » Tue Apr 12, 2022 12:20 pm

On a related note I could ironically see the price of diesel going down if there is a big switch to electric in the next few years as demand drops off and there is a surplus but I'm sure the government will tax the crap out of that if it happens :headbang: Really 15 quid for a charge that will likely do most of us a week is not bad at all and my work has 6 free to use charging stations now but only 1 electric car I can see an 8 year old Nissan leaf which seems to need charging everyday :rofl: but there only had a 80 mile range anyway with the smallest battery and at 8 years old that is probably 50 miles now as the older batteries were not that good.
Imo though if you can't charge at home electric really isn't for you as for the next few years at least cars are going to outstrip the charging network by far ,the surge in electric orders will only make this worse its already happened that the people who bought ones before went back to ICE as the network wasn't there .

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Thinking of going Electric? Some things to think about…

Post by StuBeeDoo » Wed Apr 13, 2022 6:21 am

X5Sport wrote: Tue Apr 12, 2022 10:33 amYou could try convincing her that if it does catch fire, it’s outside….. :P
Easier said than done. :( She comes from an entire family that have the most irrational fears you can imagine. :roll:
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Post by X5Sport » Wed Apr 13, 2022 10:11 am

Ah…..better not tell her that EV fires are really difficult to put out then! :police: :fuelfire: :o

Note - I’ve added a bit about charging calculations/costs and charger efficiency this morning. It may be useful to someone.
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Post by Leslie » Wed Apr 13, 2022 11:37 am

I think with home maintenance /maintenance outside the dealer network for EV's not being practical /possible anymore we are moving towards the disposable car with a build in lifespan of say 10 years , battery technology is likely to improve rapidly too now making the current models obsolete after only a few years :driving:

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Post by X5Sport » Wed Apr 13, 2022 12:07 pm

You may well be right. Battery warranties are between 8 & 10 years at present and given the power pack costs half that of the car, weighs about 200kgs and can zap you if mishandled, it’s not something your average home mechanic will be able to deal with in their drive. I’ve always fancied having a car lift but still don’t have the headroom in the garage.

I still don’t believe electric is the way forward in the longer term, it should be hydrogen. It will come but probably not before I also stop driving.
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Post by Leslie » Wed Apr 13, 2022 1:25 pm

Batteries last well for sure but they have I believe been deliberately made almost impossible to remove to ensure cars have a limited life and by the time they are needed the cost is many times the cars value . Disposable white goods come to mind when it breaks throw it in the bin and get a new one :rofl:
As for a lift you can get a low lift one that only lifts up to a metre and is moveable , these are great for taking wheels of etc and doing some servicing and will work in any garage .
As for Hydrogren we are having hydrogen buses over here soon I believe as well as some electric buses for town routes, they are made over here In Norn Ireland now . I thought hydrogren would take off too but for cars now I am just not sure if it will ever happen or if it will it's a long way off :fuelfire:

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Post by X5Sport » Thu May 12, 2022 7:40 pm

Here we are. 6 hours of work by one sparky and the domestic electrical side is all done.

Hypervolt Home 2.0 7kW ‘smart’ charge point with 10 metre cable (£800). British made of course.
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The internal install has a second consumer unit with (now required) anti-surge protection, MCB to allow that to the replaced (say following a nearby lightning strike or dodgy mains), 32A circuit breaker (must be Type A to protect against a DC leak) and 100A MCB master switch to isolate the charge point system entirely. New tails run from the company 100A feeder, split to both boards so the house and car side are completely separated.
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The thin black/white pair runs to a current transformer/active load monitoring (CT/ALMS) system designed to monitor full system load and reduce the charge rate to the car if the house needs a lot.
Feed cable is SWA Armoured 3-core 6mm with an included 4-twisted pair, Cat 5 Ethernet core to allow smart monitoring.

…..so what’s missing?

The blasted car! Production dates continue to slip (according to other places) and chip/wiring loom shortages are biting all German car manufacturers very badly. Ho hum.
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