EV Charging and Lamp Posts

I would stick with more or less standard single phase 7 kw chargers. and agree to avoid anything odd like 5 kw. And yes do double check that the available supply if sufficient. Large numbers of EV chargers may need a new substation, but a handful can SOMETIMES be added to the existing supply. 9 EV chargers each of 7 kw will be just under 100 amps per phase, presuming that a three phase supply is available. larger numbers are possible if the chargers contain some form of smart control that limits the total load.

If acceptable to the client, it might be more economic to install the chargers in groups of three at every third lamp post. One three phase cable, to three single phase chargers. Then a small single phase cable to those posts without chargers. 

What is the available supply ? And how many chargers are proposed ?

Broadgage, you need to avoid a TNC-S supply if possible, thus a private TX. This will end up the best and in the long run cheapest option.

We have no idea how often the neutral loss sircuit should be tested, 3 months, or whatever? 7kW chargers are no good for a car park where people park for an hour. We simply don't have the data!

5 kW, for reasons I don't entirely understand, seems to be common for lamppost charging. There are thousands of 5 kW Ubitricity lamppost ones in London, and a lesser number in Portsmouth. Some other towns seem to also have clusters of 5 kW ones owned by CityEV.

Thank you for all your replies.

I will state again that the EV system is not our responsibility.

However, there are three tower blocks with a 200A 3 Ph Landlord's supply (And each has a 400A 3Ph for the dwellings).

15 charging points; 3 off one block and 6 from the other two.

Loading calcs suggest the supply is sufficient, but that is down to the EV company and council clerk of works to verify.

My question is, would it be reasonable to suggest that a 5% volt drop will be sufficient?

This system design is tiny. How many flats are there? A few points will never work, it will cause fights and all kinds of problems between residents if many ever have electric cars. Totally mad. Talk to the Council and see what the policy behind this is, if it is saying only a few residents can have cars, there is obviously a severe problem!

Hi David,

I'm sorry, but that really is irrelevant to the initial post. The EV design is for bigger and better people than me.

I just want my lights to work, and the cables we have been asked to pull in be the correct size.

5 kW, for reasons I don't entirely understand, seems to be common for lamppost charging.

To allow I suspect the use of 2.5mm cable and cutouts that take a 20 or 25A fuse but might not be quite so happy with  32A.

However modern housing  developments are more likely to have a minimum underground cable cross-section of 6mm2 or higher, but of course this supplies a number of fittings in a loop-through sort of way and is dominated by voltage drop, not thermal current rating.

Mike

Typical specs for non chargepoint streetlights can make quite informative reading

http://www.auroraltd.com/images/Spec%20for%20SL%20on%20Private%20Devs%20-%20Rev%205%20June%202014.pdf

https://www.durham.gov.uk/media/3075/Street-Lighting-Specification/pdf/StreetLightingSpecification.pdf?m=636736461026070000

UKPN guidance suggests that a maximum of  5 and a bit KW may be available from some streetlamps for charging cars without supply upgrade, and perhaps more surprising without pre-notification. - As per the 'powerpoint slide below from

https://www.ukpowernetworks.co.uk/-/media/files/electric-vehicle-charging/ev-scenarios-may-2020.ashx

Note that UKPN do allow some diversity for chargers on their LV networks, - see section

7.5.1 Case 1a and Case 1b Diversity Factors.. in the more formal PDF

PDF

The answer may well depend on the LED drivers fitted in the lamp posts, assuming they are LED lamps.  Most wouldn't really care about a 10% voltage drop.  They would increase the current draw by 10% to compensate.  Get universal drivers, and they may even handle a 55% volt drop.

Would it make sense for each block to have at least one fast charger that could be used many times a day and provides a quick charge, rather than chargers that may only be used by one vehicle each day and are slow?

The biggest issue could be ensuring a fair usage policy is established and enforced to prevent people just parking in EV charging bays after their vehicles are charged.

I had an issue today with not being able to fully fill my van up with diesel.

This morning I filled up at a card payment diesel pump, then on the way home I stopped at the same garage to refill ready for tomorrow, however the pump cut off without the tank being full, because there’s a maximum limit of £99 per day and it added this mornings total to the evening total.

Not actually being able to fill up quickly and easily on demand is a nuisance that may become a problem, regardless of fuel type.

I think without intervention means without having to dig the road up rather than not being told.