The EV fact thread

[Bobby Dazzler]

At what state of charge % range?

I’m not sure I understand what you’re asking.

 

[ChipChop]

I’m not sure I understand what you’re asking.

The higher SOC ranges, 80%-100% full, take longer to charge than the earlier low% -80% SOC range.

 

[Bobby Dazzler]

The higher SOC ranges, 80%-100% full, take longer to charge than the earlier low% -80% SOC range.

That’s what confused me about your question, as you suggest in your post above, a the battery gets closer to being fully charged the charging rate is deliberately limited.

Therefore it would be illogical to assume that @clk320x was suggesting (below) that his car charged at the max output of the charger during the phase in which charging rate is deliberately limited.

Even with V3/V4 sites being full I have always got the max power output. The sites have sufficient power supplies but if this isn’t possible they are supported by ‘Mega Pack’ batteries for peak use.

 

[poormansporsche]

The higher SOC ranges, 80%-100% full, take longer to charge than the earlier low% -80% SOC range.

On a side note, on the Leaf, when over 90 % charged you only have 2 "bars" of regen available and below that the "bars" go up to 6. So I'm assuming that some of the regen energy is "lost".

Dunno if it makes much difference in the real world though.

 

[ChipChop]

That’s what confused me about your question, as you suggest in your post above, a the battery gets closer to being fully charged the charging rate is deliberately limited.

Therefore it would be illogical to assume that @clk320x was suggesting (below) that his car charged at the max output of the charger during the phase in which charging rate is deliberately limited.

Each to their own.

More accurate for the Tesla owner to say he gets a fast charge up to XX% SOC (state of charge) or within a certain SOC range (15% to 85% for example) only. Done to prevent "overfilling" and potentially damaging each cell in the battery pack apparently.

 

[ChipChop]

On a side note, on the Leaf, when over 90 % charged you only have 2 "bars" of regen available and below that the "bars" go up to 6. So I'm assuming that some of the regen energy is "lost".

Dunno if it makes much difference in the real world though.

To prevent regen overcharging the battery when it is at a high SOC possibly?

 

[markjay]

Superchargers were just an example, but I would be interested to know what the grid supply to their sites is rated at (I tried to find out, without any luck). A 5 megawatt connection is unlikely I think - that would supply 270 UK houses all simultaneously running at maximum possible consumption (normal domestic supplies are 80A, so at 230V that's 18.4 kW).

I've certainly read a fair few comments from EV drivers about getting much less than the rated maximum power from ultra-rapid chargers, even with the relatively light usage most sites have now. I don't recall whether that was Tesla or not though.

Again, you are extrapolating on current technology.

At curremt, around 4% of cars in the UK are EVs. How long before the majority of cars are EVs? We are talking about decades, at the very least.

40 years ago - in 1985 - very few people had a personal computer at home (Apple II? Commodore 64? IBM PC/G? Etc), no one had a mobile phone, there was no Internet, and no Satellite Navigation. A mere 15 years later, in 2000, all of these were not only in existence, but also commonplace. Which of these developments could have been predicted in 1985?

In fact, if we go further back, to the turn of the previous century, I challenge you to find a prediction regarding transportation - by land, sea, or air - that could have been conceivably made in 1900 and would have turned out to be true if it was made. I can think of none....

My point is that in the coming decades, battery tech will improve, charging tech will get better, efficiency will increase (the latter is crucial, as it will reduce the need for frequent charging), our energy generation capacity will evolve, the way people use cars and the way they travel in general might change, etc.

To say now that in 20 or 30 years nothing will change, and then calculate the resources we'll need to support the current technology in 30 year's time based simply on growth extrapolation, is, to my mind, foolhardy.

Then, looking at the shorter term, the other (ongoing) fallacy is that somehow everyone will be charging their cars at the same time. My 2021 Hyundai achieved 220 kW in France (admittedly, not everywhere), this means that a 15 minutes top-up buys 120 miles of high speed driving on the Autoroute. There's no reason to assume that these charging speeds won't be commonplace in the neae future. We will need around 50% more chargers than pumps at the Motorway services to be where we are now with petrol and diesel - i.e. that there's almost always going to be a free one when we approach the services.

Add to this the fact that a modern EV knows how many chargers are there in every location, their capacity, and if they are free (it's displayed on the screen), and the satnav software can easily optimise the utilisation of chargers. In fact, with the use of AI in future, we can mange charging centrally and we may actually need less chargers than we currently have pumps at the Motorway services.

Again, the idea that drivers simply glide into the nearest services when the gauge is low, is just old-fashioned ICE thinking, and will cause havoc if trying to run an a EV in the same way that ICE cars are run. Instead, the onboard computer will plot and plan a route, including dynamically changing charging stops to optimise everyone's journeys.

Sounds outlandish? So was real-time traffic 20 years ago. Then Waze came along, others copied it, and now you can't do without it.

 

[markjay]

Ok semantics but the exact wording is important because it confuses the debate of whether is squared or cubed. My understanding was that drag increases by the square of the speed but the power needed to overcome that drag increases by the cube of the speed.

So drag increases by the square of speed, and power increases by the square of the drag, right?

 

[clk320x]

That’s what confused me about your question, as you suggest in your post above, a the battery gets closer to being fully charged the charging rate is deliberately limited.

Therefore it would be illogical to assume that @clk320x was suggesting (below) that his car charged at the max output of the charger during the phase in which charging rate is deliberately limited.

Sorry Rob, yes I mean when I’m between 0% to say 40% I get the max output, naturally as the SOC increases the max output tapers. This is why you don’t ever really fill up above 80-100% on a fast charger as it’s just a waste of time. I usually just go from 5%-80% in say 30 mins.

The reply was mainly aimed at the point that even at a full site you can get the theoretical max output across all stalls with the cars being at the right conditions.

 

[BTB 500]

I definitely think it’s worth remembering that even in 2025 there’s plenty of EVs out there with quite respectable ranges already. Perhaps not Vito vans with room for several dogs etc - totally understand your specific example which is very niche for the type of journeys etc but this is hardly representative is it?

Equally though there are many brand new EVs that don't have a very respectable range on a long run at higher speeds (particularly in colder temperatures). And plenty of older generation EVs that had less range to start with (not everyone drives a brand new car). Sorted by 'typical real world range' here (motorway range would in all cases be less, even in mild weather):

EV Database

Range of full electric vehicles cheatsheet. Quick reference for all plug-in hybrid en full electric cars.

ev-database.org

As time goes by (and a relatively short time too!) EVs are getting better in terms of performance, range, charging speed etc and the infrastructure for charging is improving all the time too.

The excuses for not being able to use one are weak already and as you mention, compared to a few decades ago the expectations have changed already.

In other words, the preference for not stopping is minor. You’d have had to stop in the past and if you happen to live just a little beyond the current range for being able to do a 400 mile round trip without stopping at all (and with no changing facility at the exact arrival location too) then you would just have to change your habits.

And no doubt in the future there will be more changing infrastructure - including at the Excel centre

Yes agreed. I have no problem with any of that - I just object to general statements that long trips in EVs now are just as convenient as in an ICE.

and hopefully they’ll have a Vito equivalent with a 500+ mile range so you might be able to not have to stop at all for even 30 minutes on the way back if you don’t have any way to charge at your destination

Sadly for us that's some way off - the latest e-Vito (90 kWh battery) will only do around 150 miles on the motorway (obviously a lot less towing a caravan - yes this is a standing joke, but it's something we actually need to do in the summer months). They are also limited to 110 kW charging, so a 10-80% top up takes a minimum of 40 minutes. And price - starting at about £85k for a similar spec. to what we have now (before options) ...

So for now diesel is the only choice, although the 2.5 litre petrol hybrid from VW and Ford is interesting (but possibly not a great idea for long term ownership due to the complexity).

 

[Bellow]

But you can walk into any Nissan dealership and buy an an X-Trail or Qashqai which does that

My understanding is that they will run continuously on petrol once the battery is flat - same as the original BMW i3 (although IIRC that had a pretty small tank?).

In the case of the BMW i3, long before the tank wes depleted, the available performance was much reduced from that from a battery with a decent charge in it. That would be in the case of allowing the battery to deplete to quite a low SOC ( maybe 10%). It could IIRC be configured for the REx to come into play at a higher SOC as a provision for arriving in a city aiming to run solely on battery power.

 

[Bobby Dazzler]

So drag increases by the square of speed, and power increases by the square of the drag, right?

Drag is a function of the square of speed (v * v), and in turn power is a function of drag and speed (v), so when you combine that it’s (v) * (v * v) which is equivalent to v * v * v, or v cubed (v^3).

 

[BTB 500]

The reply was mainly aimed at the point that even at a full site you can get the theoretical max output across all stalls with the cars being at the right conditions.

Even with V3/V4 sites being full I have always got the max power output. The sites have sufficient power supplies but if this isn’t possible they are supported by ‘Mega Pack’ batteries for peak use.

Are all UK Tesla sites V3 or V4? Do all of these have Mega Pack batteries? How many charge ports are there at these sites (is it standard, or does it vary)?

 

[markjay]

Are all UK Tesla sites V3 or V4? Do all of these have Mega Pack batteries? How many charge ports are there at these sites (is it standard, or does it vary)?

I don't know about Tesla, but this is a map showing the current locations of high-speed charges (100kW to 350kW):

 

[markjay]

Equally though there are many brand new EVs that don't have a very respectable range on a long run at higher speeds (particularly in colder temperatures). And plenty of older generation EVs that had less range to start with (not everyone drives a brand new car). Sorted by 'typical real world range' here (motorway range would in all cases be less, even in mild weather):

EV Database

Range of full electric vehicles cheatsheet. Quick reference for all plug-in hybrid en full electric cars.

ev-database.org

How many city dwellers actually need an EV with 300+ miles range, though? Especially when keeping in mind that in city traffic, the real-life range will be considerably higher than the WLTP range (my car is showing around 30% recuperation per journey in slow-moving city traffic, due to frequent slowing down).

My office is 6.5 miles away from my home, it takes me 45 minutes to drive there (which is why I rarely do that - it's 30 minutes on public transport), but if I did use the car to commute to work every day, I'd only need to charge it from 50% to 80% once a week. Anyone complaining about that, should have their head examined

Yes, yes, there's the occasional unexpected long journey... but my point is that there's good reason why we should absolutely have a decent offering of small battery EVs. Firstly, these EVs are cheaper, then, they are lighter, and last, they consume less of these precious materials that people often mention. There's absolutely no reason why people should be forced into buying expensive EVs with large batteries that they do not need, due to lack of supply of cars with smaller batteries.

 

[clk320x]

Are all UK Tesla sites V3 or V4? Do all of these have Mega Pack batteries? How many charge ports are there at these sites (is it standard, or does it vary)?

See below:

No, not all Tesla Supercharger sites in the UK are V3 or V4.

Many sites are V3 Superchargers, which provide up to 250 kW per stall and have become the standard for new installations and upgrades.

Some older sites (rare now) still use V2 Superchargers, which offer a maximum of 150 kW per stall and share power between paired stalls. Tesla has been gradually upgrading V2 sites to V3, but not all have been updated yet.

V4 Superchargers are a more universal design for non-Tesla EVs. Currently these are also set at 250kW but they will likely go up to 350kW soon.

Not all UK Tesla Supercharger sites are equipped with MegaPack or other battery storage systems. Tesla installs battery storage selectively at certain Supercharger locations where grid infrastructure may be constrained or where energy cost savings can be achieved by charging the batteries during off-peak hours and using them during peak demand. In many urban or well-connected sites, Tesla relies solely on the grid, without battery backup. Some sites may use Powerpacks (Tesla’s smaller battery solution) instead of MegaPacks.

There is no standard number of stalls per site, as it depends on location demand and space availability. Small sites may have as few as 6–8 stalls, often in rural or low-traffic areas. Larger sites, especially along motorways, may have 20–40 stalls. For example South Mimms on M25 has 36, Exeter on the M5 has 32 etc…

 

[markjay]

For example South Mimms on M25 has 36, Exeter on the M5 has 32 etc…

That's 9 megawatts and 8 megawatts, respectively (if all stalls are populated simultaneously and charging at full capacity).

Superchargers were just an example, but I would be interested to know what the grid supply to their sites is rated at (I tried to find out, without any luck). A 5 megawatt connection is unlikely I think - that would supply 270 UK houses all simultaneously running at maximum possible consumption (normal domestic supplies are 80A, so at 230V that's 18.4 kW).

No idea how they do it.

 

[190]

So drag increases by the square of speed, and power increases by the square of the drag, right?

Yes and as long as we remember that aero drag is not the whole picture then we can show if the speed vs maximum power relationship is squared or nearer cubed without getting into serious formulas.

27 hp is enough to do 70mph,

To double the speed to 140 mph would require:-

If squared then 4 x 27hp = 108 Hp (good luck with doing 140 mph on only 108 HP)

If cubed then 140 mph = 8 x 27 HP = 216 HP

Now common experience tells us that the power needed to do 140 mph is certainly more than squared but somewhat less than cubed and that's because Aero drag is only part of the picture. rolling resistance increases more linearly so doubling the speed would only approx. double rolling resistance.

For the sake of simplicity lets say that of the total power required at 70mph, 20 HP was Aero and 7 HP rolling resistance
Power required to do 140 MPH is now 20 HP x 8 =160 HP + 7 x 2 =14 HP making a total of 174 HP. That sounds nearer the mark to me.

In reality it's more complex and doing this really accurately would require working everything out from first principles. The figure of 27 Hp to do 70 mph comes from some very old cars that would just about do 70 MPH on 27 HP and those cars had the aerodynamics of a brick plus the 27 HP wasn't at the wheels so the real figure would be lower. A modern car with much lower drag would do 140mph on a little less than 174 HP. Suffice to say that the above thought process shows you can't double a cars top speed by squaring the HP, it has to be nearer cubed.

 

[Bobby Dazzler]

Yes and as long as we remember that aero drag is not the whole picture then we can show if the speed vs maximum power relationship is squared or nearer cubed without getting into serious formulas.

27 hp is enough to do 70mph,

To double the speed to 140 mph would require:-

If squared then 4 x 27hp = 108 Hp (good luck with doing 140 mph on only 108 HP)

If cubed then 140 mph = 8 x 27 HP = 216 HP

Now common experience tells us that the power needed to do 140 mph is certainly more than squared but somewhat less than cubed and that's because Aero drag is only part of the picture. rolling resistance increases more linearly so doubling the speed would only approx. double rolling resistance.

For the sake of simplicity lets say that of the total power required at 70mph, 20 HP was Aero and 7 HP rolling resistance
Power required to do 140 MPH is now 20 HP x 8 =160 HP + 7 x 2 =14 HP making a total of 174 HP. That sounds nearer the mark to me.

In reality it's more complex and doing this really accurately would require working everything out from first principles. The figure of 27 Hp to do 70 mph comes from some very old cars that would just about do 70 MPH on 27 HP and those cars had the aerodynamics of a brick plus the 27 HP wasn't at the wheels so the real figure would be lower. A modern car with much lower drag would do 140mph on a little less than 174 HP. Suffice to say that the above thought process shows you can't double a cars top speed by squaring the HP, it has to be nearer cubed.

Using the CLS 55 AMG as an example, at 70 mph, the rolling resistance is around 452N and aerodynamic drag is around 427N, requiring 28kW (37PS) to maintain that speed.

Whereas at 140 mph the same CLS 55 AMG has the same rolling resistance at around 452N and aerodynamic drag is around 1708N, requiring 135kW (184PS) to maintain that speed.

That’s calculated based upon the following variables.

Transmission losses	18%​
Engine power (at the flywheel)	469​	BHP
Vehicle track​	1.599​	m
Vehicle height​	1.389​	m
Vehicle mass (weight) (kg)	1845​	kg
Drag coefficient	0.31​
Air density​	1.202​	kg/(m*m*m)
Headwind speed	0​	m/s
Gradient angle​	0​	degrees
Rolling resistance coefficient (tarmac)	0.025​

 

[BTB 500]

No, not all Tesla Supercharger sites in the UK are V3 or V4.

Many sites are V3 Superchargers, which provide up to 250 kW per stall and have become the standard for new installations and upgrades.

OK, thanks.

Some older sites (rare now) still use V2 Superchargers, which offer a maximum of 150 kW per stall and share power between paired stalls. Tesla has been gradually upgrading V2 sites to V3, but not all have been updated yet.

So when fully utilised those would only be delivering 75 kW to each car - that wouldn't require much of a grid connection.

V4 Superchargers are a more universal design for non-Tesla EVs. Currently these are also set at 250kW but they will likely go up to 350kW soon.

From Tesla's UK support page:

V3 Superchargers are capable of delivering peak charge rates up to 250kW

V4 currently supports peak rates of up to 250kW per vehicle

https://www.tesla.com/en_gb/support/charging/supercharger

"Capable of delivering peak charge rates up to 250kW" suggests to me that the peak charge rate can drop below 250 kW ... they're not guaranteeing it.

Not all UK Tesla Supercharger sites are equipped with MegaPack or other battery storage systems. Tesla installs battery storage selectively at certain Supercharger locations where grid infrastructure may be constrained or where energy cost savings can be achieved by charging the batteries during off-peak hours and using them during peak demand. In many urban or well-connected sites, Tesla relies solely on the grid, without battery backup.

From a quick Google, it appears Megapack units are only deployed at Supercharger sites with solar canopies - are there many (any?) of those in the UK??

Megapacks have been installed at Tesla Supercharger stations that also have solar canopies to help power the Megapacks. Megapacks can smooth out electric demand on the local power grid and use the stored Megapacks electricity during peak demand so there are not excessive surcharges on electricity to charge the electric vehicles.

Tesla Megapack - Wikipedia

en.wikipedia.org

Some sites may use Powerpacks (Tesla’s smaller battery solution) instead of MegaPacks.

Powerpacks only seem to hold around 200 kWh so you'd need a fair few of those at a site to make much difference?

Larger sites, especially along motorways, may have 20–40 stalls.

40 stalls all delivering 250 kW would require a 10 million watt supply from the grid. Maybe that's no problem but it seems an awful lot of power to one charging site ... some UK power plants produce less than that!

Open Infrastructure Map

List of power plants in the United Kingdom from OpenStreetMap

openinframap.org