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
).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.
Never anthropomorphise computers. They hate that.
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.
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 
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. 
