Charging points for electric cars

Discussion in 'Electricians' Talk' started by Bob Rathbone, Jul 9, 2018.

  1. Bob Rathbone

    Bob Rathbone Screwfix Select

    Well, this morning our government announced that they want all new homes to be fitted with electric car charging points and every lamp post to have a charging point fitted to it. This displays quite clearly how ill informed are our politicians of the realities of charging thousands of cars, the energy it will draw from the system and the service cable sizes provided to street furniture such as lamp posts. On a separate issue, does this mean that I will be able to park on double yellow lines provided I have plugged in my car for a charge?
    What does the team think?
     
  2. Pollowick

    Pollowick Screwfix Select

    It has good intent but certainly demonstrates a lack of understanding as to what is required to support the charging points. For example: will they charge a premium rate during the peak hours? will overnight charging be at low cost? Will you be able to plug in and tell the system to wait until cheap rates become available?
     
  3. rogerk101

    rogerk101 Screwfix Select

    Home charge points will not be the quick charging points ... rather the overnight and trickle ones, which don't require especially large currents.
    Think back to a few years back, in the days when almost every room had at least one 100W light bulb, several rooms had a 2000W electric heater, and many more ovens and hobs were inefficient and electric before gas became widespread. The electrical infrastructure coped then, and it will cope again.

    Governments decide the what ... engineers decide the how.
     
  4. Bob Rathbone

    Bob Rathbone Screwfix Select

    I agree that the home chargers will be 3 or 6 Kw, but the number of these will be huge, every car at every home in every street, that is the intended outcome. We currently do not have sufficient generating capacity to supply our own demand without import from France at peak times and their are no plans to substantially increase capacity in future (Hinkley point is a small step).
     
  5. The only thing correct there roger is the 100w lamp.
    The vast majority of people had gas cookers and did not want electric, and I did not know anyone who had 2kw heaters in several rooms,just a coal fire in the front room.
     
  6. rogerk101

    rogerk101 Screwfix Select

    The biggest hindrance to adoption of electric cars is the shortage of charging facilities. The biggest hindrance to increasing charging facilities is the shortage of electric cars. Catch 22.
    The government is taking a very small step here, but a journey of 1000 miles begins with the first step.
    What would you prefer ... that the government just sign the international carbon dioxide limiting agreements and then does nothing?
    The only universal constant is change.
    It is not beyond the wit of man to convert from petrol/diesel vehicles to electrical.
     
  7. HappyHacker

    HappyHacker Active Member

    When, for my sins, I was working in London I would walk back to my flat through Notting Hill and surrounding areas. There was no off street parking for the cars so the roads were full of parked cars some of which had obviously not moved for some time. The same situation exists in my little one horse village that appears in the Doomsday book. Arranging charging for these is going to be problematic even if they do manage to dig up all the roads to put charging points on lampposts, every 200 yards in my village and not all where you could park.

    I think in time technology may provide an alternative, with shared car ownership becoming more common, especially if automation allows the driverless car to turn up at your house when you order one for you to drive away. Otherwise if we continue with the drive to electric I am not convinced that our infrastructure will cope despite the optimistic reports from various central bodies. Especially of the drive to wind and solar is not matched with sone other form of storage for when the wind does not blow at night when we will be trying to charge a large number of these cars.
     
  8. Pollowick

    Pollowick Screwfix Select

    My local Costco has 20 or more points and the usage is extremely low. It is very rare to see even one in use.
     
  9. Dr Bodgit

    Dr Bodgit Super Member

    Over the past several years we've seen virgin and like digging up roads and pavements to lay fibre optic cable for all those potato couch types who have nothing else to do but stay in all day watching carp films.

    I can envisage, in a few years time, the roads will be dug up all over again as electric companies have to upgrade their power cables to cater for more and more car charging points.
     
    rogerk101 likes this.
  10. rogerk101

    rogerk101 Screwfix Select

    I've often wondered why councils don't dig some nice deep and broad trenches alongside every road and lay a network of big diameter concrete pipes with manholes every 50 meters or so. The result would be a network of 'service tunnels' alongside every road in every part of each council's jurisdiction.
    Then, when Virgin, Sky, Thames Water, EDF, or whoever wants to run a new service, they apply to the council, pay their installation and monthly fees, and they can then provide their service without having to redig and repatch everything. Imagine walking on pavements that haven't been patched 20 times in the last 20 years as water, gas, electricity, phone, etc. companies add their latest 'technology' to our neighbourhoods.
    It would also provide our councils with much needed reliable recurring revenue streams. Wins all round.
     
  11. Pollowick

    Pollowick Screwfix Select

    They would need to put numerous ducts - one for domestic power (230v), another for the HV lines, another for water, another for gas, more sets for communications &c. To ensure separation.

    There are defined locations - distance from kerb and depth for each service so they all know what is where. Numerous times I have seen one of te providers start digging out and smash the infrastructure of others,for example green cable/fibre TV ducts, and no bother repairing it, just back fill and let the ducts get blocked. The the cable company wants to run a new fibre - and they have to excavate to remove te blockage. Or when a cable TV company ran ducts, less than 100mm under a footpath, they just smashed through drain pipes from roadside gullies resulting in continual flooding of a road.

    BT has some major ducts and service tunnels throughout the centre of London - they were willing to rent space out to other providers. But no, they demanded access free of charge!
     
  12. rogerk101

    rogerk101 Screwfix Select

    Precisely my point ... there wouldn't need to be such 'defined locations' (distances from kerb, depth from ground surface, etc.) if each service provider's service pipes/wires/fibres were readily identifiable. For example, all fibre optic cables are blue, but Virgin's ones have a yellow stripe, Sky's ones have a green stripe, etc. (Yes, they all seem to spend their time acquiring each other, but that, too, is not beyond the with of man.)
     
  13. Pollowick

    Pollowick Screwfix Select

    There are good reasons for having defined locations - that way a provider only needs to dig once rather than dig and see. Water needs to be a minimum distance below to stop freezing, power and 'phone need to be kept separate to stop crosstalk/noise, gas at a minimum depth to protect it from heavy loads above.
     
  14. Bob Rathbone

    Bob Rathbone Screwfix Select

    I think we are losing track of the original issues here. Roger, I support the change to electric but we must have the supportive infrastructure to power the charging points, wherever they are and how big they are. We do not have this at present.
     
    btiw2 likes this.
  15. peter palmer

    peter palmer Screwfix Select

    Surely we had the infrastructure when we had heavy engineering. A single electric arc blast furnace from the 50s would use enough power to charge thousands upon thousands of cars.
     
  16. btiw2

    btiw2 Screwfix Select

    I agree, but I think we have to acknowledge the scale of the transformation currently needed.

    Petrol has an energy density of 36 megajoules per litre. A petrol pump dispenses at roughly 50 litres per minutes.
    This means a petrol pump can be considered a 30 megawatt energy dispenser. That's a huge number.

    When we measure domestic power in the kilowatts, and street lights are... what? hundreds of watts (guessing)?

    It's difficult to see how we upgrade our electrical infrastructure through four orders of magnitude.

    Maybe new tech could give us super-duper-capacitors which we change out, but then wtf have lampposts got to do with anything.

    I'm not sure politicians really understand the physics of these numbers (which was, I think, part of your point).
     
  17. btiw2

    btiw2 Screwfix Select

    From wikipedia:
    The largest scrap-only furnace (in terms of tapping weight and transformer rating) is a DC furnace operated by Tokyo Steel in Japan, with a tap weight of 420 metric tonnes and fed by eight 32MVA transformers for 256MVA total power.

    256 MVA = 256 megawatts. So roughly 10 petrol pumps of power.
    10 petrol pumps would probably be sufficient for a small town of say 20,000 people. So yeah, I guess your numbers check out.
     
  18. Pollowick

    Pollowick Screwfix Select


    But that is 30 MW/minute and will keep a car going for 10 hours or so.

    An electric car has a typical range of about half that of a petrol vehicle, so would require a 15MW/min supply. However, they are often charged overnight for say 8 hours - 500 minutes so a 30 kW or 120 A supply would achieve it. Still a very high-load but most will only require maybe 10% of that each day which does gve a little more perspective.

    Intelligent management of charging pints is required - so when you plug in, a reading is taken and if the batteries are near empty charging starts immediately, or if just in need of a top up, the system will wait until overall loads are low and then start the charge cycle.
     
  19. btiw2

    btiw2 Screwfix Select

    I don't know what MW/min mean. Watts already have the time component built in. They're joules per second. So a petrol pump is 30 MJ per second. I'll assume it was a typo and put pedantry aside.

    I agree, and also there's another advantage to electric cars. They're typically 2-3 times more efficient in energy usage than setting fire to petrol.

    You're certainly right that any infrastructure improvement will be useful for people with short commutes who have lots of time to recharge.
    Some people don't need to charge a car in two minutes with enough energy to last them the month. A slow steady charge works for them.
    And double the delivery of the infrastructure and you slightly extend the number of people for whom electric cars become viable. I'm not anti-electric.

    But if we want to replace petrol then we'd need to cater for people who want to travel hundreds of miles without wanting to charge overnight. I can't see how this can be done. The numbers are too frightening.

    Or perhaps we shouldn't try. Perhaps we'll be stuck with dual fuel until a major technological breakthrough in electrical storage. Petrol for long journeys and electric for popping to the shops?
     
  20. Dr Bodgit

    Dr Bodgit Super Member

    I've just been on a few days holibobs to Gods own country, 300 miles there and back with a B&B in the middle of nowhere. How are electric vehicles going to content with that? Dual fuel (or self charging hybrid) seems the way to go for now at least.
     

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