My Urban Car
Tesla charging at a lamp post

Getting local EV Public Charging right – Part 2 local charging mix

In part 2 we will look at the different types of charging you need, the most common mistakes and how to avoid them.

Table Of Contents

Aiming for acceptable utilisation rates for local chargers

Firstly let’s make it clear what we mean by utilisation. Imagine you built and owned a petrol station and only one customer a week visited. You would probably fairly quickly ask yourself why none of the cars driving past were stopping to fill up. You might ask yourself why they were filling up elsewhere. Was your fuel competitively priced as we covered in part 1? Or was it something else? Today we are covering mix of EV charging available and when they are used by EV owners.

What are the key components of a successful local public charging strategy?

  1. Cost of charging
  2. local charging mix
  3. Useability. Reliability, ease of use and payment

2. Local charging mix

Your Customers are EV owners- what do they need?

This might seem obvious but many EV charging installations have been made across the country with almost no thought to this. Each type is useful to EV owners in different situations.

Slow AC charging

  • in this speed range chargers will offer AC (alternating current) charging only
  • While EV’s can charge very quickly on DC (direct current) chargers most have very low maximum speeds they can charge at using AC chargers
  • Many plugin hybrids and older EVs can charge at a max of 3.5 kW
  • Most newer EV’s can charge at a maximum of 7.2kW
  • Some EV’s can charge at up to 11kW on AC
  • AC charging above 11 kW is fairly pointless. To our knowledge only 2 cars (Tesla Model S and Model X can charge at 16kW while a single EV on sale can charge above this speed on AC. The 2020 Renault Zoe can charge at 22kW

Advice – As at 2020 there seems to be no point investing extra money on AC chargers that are above 7.2kW or 11kW speeds. EV owners wanting to charge faster than 11kW (apart from Renault Zoe owners) will generally use DC chargers

Could future models offer faster AC charging than 11kW?

It’s possible but unlikely because anyone wanting fast charging does it using much faster DC chargers that at the moment span 50kW at the slow end to 350kW at the fastest. As a result faster AC charging is a bit like asking for a faster snail instead of using a horse.

Who uses slow AC charging?
  • these chargers are ideal for charging somewhere your EV will be parked anyway, the longer the better. This could include home, work, leisure facilities and shopping locations
  • 7kW chargers are likely to add around 20 miles of range in an hour so even 3 hours is only going to add 60 miles
  • An EV owner is very unlikely to sit in a vehicle on a slow AC charger or remain in the vicinity or be around to unplug promptly
  • so local facilities are not vital nor do they need to be grouped together

Slow AC – Lamp post charging 

Advantages

  • lamp posts allow shared bays between EVs and non EVs especially 3 or more are installed in a street.
  • Cheaper to install and don’t clutter or block pavements
  • with charging costs as low as 24p a kWh lamp posts deliver good value public charging
  • lamp posts without bays do allow EV’s to park up and connect whether the charge port is front or back or driver or passenger side provided the space is free.

Disadvantages

  • These lamp posts are slow usually around 7kW
  • As EV battery sizes grow to 70kWh and above the 7kW charging speed works best for smaller top ups or full overnight charging could take 10 hrs or more
  • Lamp post chargers need increasingly to be used in conjunction with dedicated EV bays as they are popular. The fact they are unobtrusive means they tend to be blocked by internal combustion cars, by accident but sometimes for weeks at a time.
    Option A Start with a bay for one lampost in a street and mark out extra EV only bays once existing ones are in regular use. Perhaps over 7 charges a week averaged over a month would trigger another EV only bay
    Option B Give all lamp posts dedicated EV bays which require the plugin vehicle to be connected) but only enforced for a limited time.. eg 9.30 until 10.30am. This makes the bay available to any car but they will know they need to move by the next morning. This would make a big difference to availability (some cars block the chargers for days and weeks) while minimising inconvenience
  • some older lamp posts are fairly useless because they require special cables that are very expensive. Only those that anyone can plug in using a standard cable should be installed.

Advice – Lamp post charging is probably the best way to roll out charging that’s good value for EV owners in residential streets with low cost and impact.

Slow AC – Charging posts 

These quite bulky posts are seen quite widely in London and have dedicated parking bays. They were amongst the oldest charging types and for now are struggling to find a purpose as they are prohibitively expensive as we covered in part 1.

Advantages

  • Highly visible and allow standard cables to be used and therefore could be useful for visiting EVs
  • they often come with dedicated parking bays sometimes in popular locations so effectively they come “parking included”. This could be economic for non residents visiting but is uneconomic for residents who already have a parking permit in that area

Disadvantages

  • To justify the large size and pavement space taken they should be be much faster than the speed of a lamp post charger & upgraded to be faster DC rapid speeds in future. These chargers should be eventually be DC 50kW or more
  • Often installed in 2’s and 3s. This probably makes sense economically but on some residential streets opposition might be reduced if not all bays were EV only to begin with
  • these post charging posts, in London anyway, tend to be both slow and massively overpriced. As a result they appear to indicate lack of demand for charging when they are simply not providing a good enough service for the money. The high cost entirely removes any cost advantages of running most EV’s compared to diesel or petrol cars.
  • Some post chargers in London and the rest of the UK are run on app or membership models. These may work for people using them frequently but are very awkward for occasional visitors who have to give their name, address, bank details or sometimes even nationality and direct debit mandates and sign in just to get a single charge

Medium speed DC charging at 50kW

These slower DC chargers are still being installed across the UK even though they’re relatively low speed won’t make them chargers of choice for EV owners on a trip

  • Should be on EV only bays.
  • DC chargers or slow chargers near retail and eating establishments will encourage owners to spend time and money locally as they charge
Who uses 50kW chargers?
  • Some visitors will use these along with local EV drivers needing to charge faster than on AC
  • For smaller EV’s an hour of charging might fully charge the battery. For larger EV’s it might only provide 50% charge in an hr
  • Like slow AC chargers most owners won’t stay in the vehicle for a 50kW charge if there is anything else to do nearby
  • Unlike slow AC chargers owners are likely to remain nearby and mostly be prepared to move the car soon after a charge completes
  • Needs to be in a safe location
  • 50kW locations should be grouped with 3 or more chargers together is a plus for safety and to help ensure availability

Fast DC charging above 50kW primarily 100kW or 150kW and up to 350kW

These will increasingly take over from 50kW chargers. Many cars and vans can accept DC charging at 100kW or more and new models will manage much more

What is the use case for 100kW+ chargers
  • EVs will treat these charger locations as a destination in their own right
  • These charger locations should be grouped in sufficient numbers of chargers units to guarantee good availability. Ideally 8 chargers or more.. at least 4.
  • owners will usually remain on site or in their vehicle as many charges will be under 30 minutes. They should move as soon as a charge is complete
  • toilet and some refreshment facilities should be on site
  • Drivers waiting in their vehicles while charging will place a much higher priority on a safe, well used, well lit location day or nights than is this case with slower chargers
  • the arrangement of these chargers should be closest to a petrol station
  • while they are more expensive to install a faster DC charger may be able to charge 3x as many EVs in an hour as a 50kW charger and 20x more than a 7kW slow AC charger.
  • It may be advantageous to put a mixed bank of slightly cheaper 50kW chargers next to 150kW chargers at the same location. This will encourage slower charging EV’s to use slower charging charge points

The key consideration for a successful rollout of EV chargers in an area are:

  • A mix of fast and lamp post charging across an area provide a perfect mix for current EV’s.
  • Ensuring EV only space provision for slow AC chargers is adjusted according to demand
  • Charging cost for slow AC charging should be as similar as possible for on street as it would be from home
  • We believe that all areas should include at least 100kW and ideally 150kW in their charging mix. If they are reliable then owners know that, if they need it, they can get a substantial charge even if about to go on a long journey. This reduces the need for “advance planning” when and where to charge that has been a requirement for many EV owners till now

Part 3: is some EV charging being installed that is difficult or impossible to use?

David Nicholson

David Nicholson Is the founder of Rivergecko Ltd & MyUrbanCar which provide consultancy and advice for drivers and fleets to speed the transition from dirty fossil fuel transport to clean vehicles powered by renewable energy on land water and air.

The @MyUrbanCar twitter feed is a source of news & reviews of electric & plugin cars and vans in the UK.
The @rivergecko twitter feed & www.myurbancar.com websites bring news and opinion on cleantech transport including cars, vans, buses, trucks, shipping, rail & aviation as well as autonomous vehicles & renewable energy, air pollution & motor industry news.

David Nicholson has worked as an underwriter at Lloyd's of London since the 1980's. His interest in technology goes back many years including interactive mapping, apps, green tech, boats, solar and cars.

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