Not from 0-100% in one night. It would take at least ten hours. Four hours at 5p at 7kw is £1.40, Six hours at say 13p is £5.46. Add them together and that makes about £7 to go from 0-100% in one night. Going from 20-80% in one night would cost maybe £3.30ish.
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Supercharging more expensive than petrol?
- Thread starter StuC
- Start date
MrBadger
Badger out
Schoolboy maths and estimates
75kWh @11kW is still just shy of 7 hours.
4h @ 11kW = 44kWh = £2.20 @ 5p/kWh
2.8h @ 11kW = 30.8kWh = ~£4.30 @ 14p/kWh
6.8 hours @ 11kW = 74.8kWh = ~£6.50
Sean.
Active Member
3-phase AC is just...yawn. Now 50 kW DC at home is where it’s rocking.
ACarneiro
Active Member
Electricity is expensive in Aus as they don’t have thousands of miles of coastline for cheap wind power or massive uninhabitable areas of land where the sun shines a lot.
No disagreement with the maths, but it made me think - do we have modern data on how efficient the charging process is? In other words, if we use 50kWh from our mains supply, how many kWh ends up as useful energy? I saw some old data from research done in 2013 which suggested an efficiency around 85%, implying in my example above that of the 50kWh that is drawn from the mains supply, only 42.5kWh is available to power the car. I'm guessing that efficiency has improved over the intervening 7 years. Any more recent data?
MrBadger
Badger out
Nothing scientific like putting a meter on the incoming power line, but using the values reported from TeslaFi (energy consumed/'used' vs energy 'added'), it can report a wide range of values. Note TeslaFi gets 'added' from the Tesla Api but calculates 'used' - sum of energy (calculated from P=IV) reported for each poll interval.
However, 90%+ efficiency reported is very common, even at 10A charge. Our 2-1/2 hour charge this morning, nearly 95%. But a few days back, 85%. There will obviously be other losses on top of these.
Ive seen far worse, although normally shorter charges.
I had a bit of insomnia a few weeks back and was sad enough to actually follow the early parts of the drive. It took a long time for the first 1% to be accumulated, then it sped up. Makes sense as battery gets into its optimal charge conditions and also voltage fluctuates over time.
Last edited:
Sean.
Active Member
If you meter your charger supply, and charge to the same level you can very easily work out the “true” total energy and consumption Wh/mile figures of what’s “put in” and “got out”.
This will take into account:
- charge unit losses (should be minimal for a typical domestic AC wall box)
- on-board AC to DC converter loss
- battery and driveline loss
The individual losses are kind of immaterial it’s the end-to-end figure that’s important. 80 to 85% end to end would be good going.
CyberGus
Not Just a Member
Petrol cost is at historic lows due to the pandemic and lowered demand. It wasn't that long ago that oil cost 2x what it does now.
Cost of fossil fuels fluctuates wildly compared to the relatively-stable cost of electrical power. Even if EV costs more to fuel than ICE today, the total cost of ownership is much lower overall.
Cost of fossil fuels fluctuates wildly compared to the relatively-stable cost of electrical power. Even if EV costs more to fuel than ICE today, the total cost of ownership is much lower overall.
It isn't cheaper today or any other day to date. In case anyone missed it (given the thread title) ... charging an EV remains massively cheaper than petrol/diesel in the UK ... the title of this thread refers to an article in Australia so is only tenuously relevant to the this UK/Ireland part of the forum, other than for general interest.
Yep. I have 3-phase AC at home, but just use a regular 7kW charger as the M3's 11kWh limit doesn't justify going beyond. If the M3 could take 22kWh AC charging, though, that would be a different matter...
The author is some climate denier nut job with a book coming out about how we've all been hoaxed by the environment changing right in front of our eyes.
What is amazing is how these things get traction on the internet. But there seems to be a captive audience for this garbage.
What is amazing is how these things get traction on the internet. But there seems to be a captive audience for this garbage.
Drew57
Active ember
There's an article in todays' Times about Gov't studies into how to recover lost tax revenue as EVs will replace ICE
Charges for using roads to fill £40bn black hole | News | The Times
"...Rishi Sunak is considering plans to charge motorists for using Britain’s roads amid concerns over a £40 billion tax shortfall created by the switch to electric cars...Mr Sunak is said to be “very interested” in the idea of a national road pricing scheme despite concerns in the Treasury about the cost of the green agenda, including that revenues from fuel duty, one of the government’s largest revenue earners, are set to vanish...The rise in popularity of electric cars could leave the Treasury with a £40 billion funding gap.
...Fuel duty, which is charged at 57.95p a litre on petrol and diesel vehicles, is on course to raise £27.5 billion this financial year, equivalent to 1.3 per cent of national income, according to latest forecasts. Vehicle excise duty, which is charged on the purchase of cars based on the level of emissions, will raise £7.1 billion, while VAT on fuel is worth £5.7 billion..."
Charges for using roads to fill £40bn black hole | News | The Times
"...Rishi Sunak is considering plans to charge motorists for using Britain’s roads amid concerns over a £40 billion tax shortfall created by the switch to electric cars...Mr Sunak is said to be “very interested” in the idea of a national road pricing scheme despite concerns in the Treasury about the cost of the green agenda, including that revenues from fuel duty, one of the government’s largest revenue earners, are set to vanish...The rise in popularity of electric cars could leave the Treasury with a £40 billion funding gap.
...Fuel duty, which is charged at 57.95p a litre on petrol and diesel vehicles, is on course to raise £27.5 billion this financial year, equivalent to 1.3 per cent of national income, according to latest forecasts. Vehicle excise duty, which is charged on the purchase of cars based on the level of emissions, will raise £7.1 billion, while VAT on fuel is worth £5.7 billion..."
MrBadger
Badger out
Similar threads
