The EV fact thread

[MikeInWimbledon]

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Rest assured, Guv, there's no sign of an electric equivalent of a proper truck yet. The F150 Lightning is but a damp squib. (20,000 sold in 2023 compared to 700,000 full fat F150's)

And let's not start looking at all the convertible drivers who can't see an EV convertible that vaguely meets their needs or budget.

 

[MikeInWimbledon]

Depends a bit on where you live though - there are only three charging sites (12 outlets in total) in our nearest town, and none of them are free. The 22 kW ones at Aldi are 59p / kWh.

Why would you go to your nearest town when you can charge for peanuts at home?

Or are you in a multimillionaires apartment block with no off-street parking, like them there City dwellers?

 

[BTB 500]

As for Fleet News' article about EV power loss, it's great proof of the stupidity of some journalists. (I used to run a 300 vehicle fleet, and worked with salesmen for a more than a decade as well).

So, you have a company credit card or charge card that gives you electricity for your EV, charged direct to the company. Your wife, girlfriend, loved one, or good buddy also runs an EV. Need I say more? (Doesn't work with a Tesla supercharger, but it does for the rest). (Old Fleet Management tradition - the employee can't push it too far, but an extra 10-20%?)

In other news, some employees charge meals and drinks to their company credit cards for friends as well as themselves.

The data on loss rates in that article came from testing done by ADAC in Germany (equivalent to the AA here, but much larger).

 

[MikeInWimbledon]

The data on loss rates in that article came from testing done by ADAC in Germany (equivalent to the AA here, but much larger).

The mis-quoted data on loss rates....

ADAC didn't say that Granny cables lose 30%. Think about it. Where does that energy go? Is it like light fittings without bulbs: the electricity just leaks into the air?

ADAC said that a granny cable "could" lose up to 30%, if charging at full rate 13A rate, through heat loss throughout the building, not just the cable.

Much in the same way that my E55 used to do 8mpg on a two mile school run on a winter's morning.

 

[BTB 500]

Why would you go to your nearest town when you can charge for peanuts at home?

I was replying to the point about people seeking out very cheap (or free) charging. If you live in that town and aren't able to charge at home then 59p / kWh is currently the cheapest you can run an EV for (if you don't mind waiting at a 22 kW charger).

 

[190]

Charging losses of up to 30% from a granny cable though, so in the worst case 8p per kWh could really be 10.4p per kWh when driving. Loss when charging via a wall box is 'only' up to 10%.

I really think there is some misunderstanding going on in the linked article. No way can you lose 30% in a charging cable as it would be absorbing near 1 kw and be getting very seriously warm.

13A sockets should in most cases be fed by two 2.5mm2 cables which is good for 30 A so voltage drop to that point is minimal and assuredly not the issue. Provided the charging cable is correctly sized and I would expect a minimum of 1.5mm2 then the loss should no more the a few percent. Wherever the 30 % is going it's not being dissipated in the cables as losses of that magnitude would produce very noticeable heat.

Installing a wall box fed directly from the distribution board is going to be optimal but using a 13 amp charging cable should also be safe provided the house wiring and charging cable are up to spec. You might not want to do it in an old house though and certainly not where cables have the old rubber insulation.

 

[BTB 500]

The mis-quoted data on loss rates....

ADAC didn't say that Granny cables lose 30%. Think about it. Where does that energy go? Is it like light fittings without bulbs: the electricity just leaks into the air?

Did you actually read the ADAC report? They quote total charging losses as 10-30% when using a wall socket:




Their specific testing on a small sample of vehicles measured 12.7% to 24.2% loss.

 

[BTB 500]

I really think there is some misunderstanding going on in the linked article. No way can you lose 30% in a charging cable as it would be absorbing near 1 kw and be getting very seriously warm.

As above the majority of the loss occurs in the car's on-board charger (which converts mains AC to DC). These require cooling, which of course consumes power in itself.

 

[markjay]

Sustainable? 'Free' could (and probably will) disappear in an instant.

EV incentive are being gradually withdrawn, but they won't disappear as long as there's a viable ICE alternative... once ICE becomes unavailable or unaffordable (due to taxation), the EV subsidies will be completely gone, but not before.

When it takes merely five minutes at a filling station, the iCE driver isn't missing much there.

I may have not made myself clear on this, I was referring to a scenario where an employee is driving his or her company car to work, plugs it in at the company car park, and then goes to their desk to do whatever it is that they do for their job. They may move the car to another spot during lunch break... then drive home at the end of the day. In this scenario, the energy cost for the employee will be nil (other than on the occasion that they embark on a long car journey at the weekend or while on holiday). Again, this will only apply to these people whose particular circumstances allow it... but there would be quite a few of them I imagine. This is just to highlight my point that the question of cost-per-mile is meaningless without having additional specific data regarding how and where the car will be used.

The UK housing market is some model to base EV recharge pricing on. But yes, it's looking a lot like pricing will be based on rate of recharging, availability of said recharging facility, and time of day. None of these limitations apply to liquid combustible fuels.

The house pricing was a generic example, I could provide others: How much does a meal at a restaurant cost in the UK? How much does an airline ticket cost? What is the price of a pair of shoes? Etc etc. What all these examples have in common with EV per-mile energy costs, is that any one figure given in answer will be meaningless, without the data regarding the additional particular circumstances. We can sit here and discuss various cost scenarios until the cows come home, but then one EV motorist will pay 85p per kW while the other will be driving for free.

 

[markjay]

As above the majority of the loss occurs in the car's on-board charger (which converts mains AC to DC). These require cooling, which of course consumes power in itself.

Based on the first law of thermodynamics, any losses will be either be heat (the vast majority), or kinetic energy required to spin any fans in the system (very little).

 

[markjay]

Wots an EV, just got to grips with decimal money
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I measure speed in furlong per fortnight...

 

[BTB 500]

Based on the first law of thermodynamics, any losses will be either be heat (the vast majority), or kinetic energy required to spin any fans in the system (very little).

Absolutely - it's heat, which at low levels dissipates naturally (e.g. in the cables) or requires forced cooling (e.g. charger and often battery).

 

[BTB 500]

Further explanation from ADAC. They factor in charging losses when looking at EV running costs, rather than assuming that the only power used (and paid for) is what the vehicle consumes when driving.

 

[markjay]

Depends a bit on where you live though - there are only three charging sites (12 outlets in total) in our nearest town, and none of them are free. The 22 kW ones at Aldi are 59p / kWh.

Are you checking this using Map of electric charging points for electric cars UK: Zapmap ?

 

[BTB 500]

Are you checking this using Map of electric charging points for electric cars UK: Zapmap ?

Yes, also checked Google Maps which shows the same 3 sites (but obviously without the details on rates etc.). Google actually shows the Aldi charge point (operated by Shell) as being in somebody's back garden though

 

[MikeInWimbledon]

Did you actually read the ADAC report? They quote total charging losses as 10-30% when using a wall socket:

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Their specific testing on a small sample of vehicles measured 12.7% to 24.2% loss.


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I did, which is why I said you were misquoting it when you said “Charging losses of up to 30% from a granny cable”

 

[Bellow]

How do I secure the house at night if I have a 'granny cable' running out through an open window?

 

[markjay]

How do I secure the house at night if I have a 'granny cable' running out through an open window?

I suppose you can get an electrician to fit a simple outdoor mains socket on the external wall - or you could fit a cat flap.....

But how do you secure your house on a hot summer day (or night)? Not everyone has Aircon.

Incidentally, I don't charge from my home supply, but if I did then it wouldn't be an issue because living on the ground floor in central London we have bars on the windows anyway.

 

[ALFAitalia]

Most modern windows have a "night vent" setting which means you can lock it with a half inch or so gap. Been like that on most windows for decades.

 

[markjay]

Most modern windows have a "night vent" setting which means you can lock it with a half inch or so gap. Been like that on most windows for decades.

This goes back to what I said earlier, i.e. circumstances matter. Some people will be able to charge using a granny cable, some won't.... it's pointless taking one extreme scenario and putting it up there as a reason to have - or to not have - an EVs.