Trial electric vehicles

[stripeypaw]

Anyone on here involved in this?

https://news.google.com/articles/CBMicG ... id=GB%3Aen

[TrueBlueTerrier]

You may not get any replies here, if anyone does they will have outed where they work and that's not something we advise anyone to do on RMC.

[Norfolk 'N' Chance]

Im probably a sitting duck here, but I quite like the concept of these carts. If the government are hell bent of banning the production of new diesel vehicles from 2030, any research and devlopment now into what might work and whats best suited for towns and rural areas only has to be a good thing.

If readers will allow me, Id like to take this EV trial slightly away from the original posters direction.

One of the biggest problems I foresee, not just for RM but for all fleet vehicle operators and vehicle hire companies for that matter is that the existing incoming electricity supply from the Distribution Network Operator (DNO), will be the limiting factor in the first phase of any EV fleet roll out.

Now my experience of individual DO's is limited. But I'd have a good estimate based on my knowledge of electrical installations, that a lot of DO's around the country probably have a standard 100A to 200Amp per phase, 3phase incoming supply. This is pretty standard for commercial premises and the sort of tin shed modern out of town industrial units etc. Its possible that some city area DO's could have a 400A per phase supply though.

As a general rule for supplies greater than 400amp per phase, the DNO's set up tends to be a HV supply with a customer owned 11kV/400V transformer and low voltage Air Circuit breaker and LV board/Cabinet. From this you could derive 800, 1200, even 1600Amps per phase.

I cant imagine the carts in this trial are the new 22kW high capacity charging type that a lot of the EV manufacturers are now producing, and in an effort to keep the maths simple id like to just work through an example of the electrical current drawn by one single 22kW EV.

22kilowats is 22,000 watts. Divide this by the uk nominal voltage (230v) and you get circa 95Amps. Extrapolate that out and for a small DO with a 3x100Amp incoming supply, it could at peak charging current, charge 3 of the 22kW EV's over night. - i.e. not that many!

So assuming the carts are 5-6kw (roughly a quarter of the new EV standard) then a typical DO could probably charge around 9-12 per night without significantly upgrading the existing electrical infrastructure (mainly the feeder cable size entering the property). Initially this relatively small number of carts maybe sufficient for many DO's but what about when extra EV's come on line?

The distribution companies have new connections departments and will subject to the load density and capacity of their network in any given area, be able to increase their supply for a tidy sum! The bigger issue is that it is foreseeable that in some areas, the overnight electrical loadings will significantly increase as more businesses convert to EV's, and there may not be network capacity. This very issue was being flagged up when i worked for a DNO 20 years ago, yet major investment into the network for EV charging has yet to roll out widely. For any network reinforcement it will require new cables, new transformers, etc and the associated roadworks and disruption that this type of work creates.

So in summary, my point was really this. These carts and other EV's may well prove to be useful for RM, but widescale roll out in large numbers will require a lot of infrastructure investment, not just at the DO level but also to the wider public electricity network.

If any of the readers are 3,4,5+ car families. When the time comes how will you manage to charge more than one EV at at time from your 80/100amp supply?

Regards Norfolk

[97gaz]

I think you are confusing kW with kWh. The carts will be rated in kWh so won't actually be using 22kw at any one time. Same goes for the supply. My nephew is a big EV fan and has had 3-4 different EVs. His current one is a Golf. I was at their house in the summer after they asked me to try to find a nuisance tripping problem. I noticed the charger he had fitted for free when he bought his first EV is run off a 16A breaker.

The biggest issue for me is the supply and demand situation. For years now we have regularly gone to the wire when it comes to supply matching demand. It's not a new thing and has been a issue since I worked in the Power Generation Industry for nearly twenty years on and off from 74 -96. With the demise of coal and the increase in gas fired stations which are usually much smaller than the traditional coal fired stations, I think we are headed for trouble. We currently buy a huge chunk of the gas we use from other countries. The same for the electricity we buy from French nuclear power stations. Even before coal became a dirty word, we used to buy it in from South Africa and Russia despite there reputedly being 300years worth under our feet.

I am a big fan of renewables. Wind and solar are great but the electricity generated cannot be stored. If we have a dull day with no wind then we are screwed without there being a mix of traditional power stations on standby. That in itself is expensive. Throw 30m electric cars and electricity hungry air scourced boilers into the mix and we are up the swannie.

In my view we need to be building Nuclear powered stations and building them now. Yes they are expensive to run and create their own problems regarding the waste but we must have security of supply or we will be beholden to other nations to keep our lights on.

We also need to be ramping up the number of solar and wind farms massively.

[Norfolk 'N' Chance]

I think you are confusing kW with kWh. The carts will be rated in kWh so won't actually be using 22kw at any one time. Same goes for the supply. My nephew is a big EV fan and has had 3-4 different EVs. His current one is a Golf. I was at their house in the summer after they asked me to try to find a nuisance tripping problem. I noticed the charger he had fitted for free when he bought his first EV is run off a 16A breaker.

The biggest issue for me is the supply and demand situation. For years now we have regularly gone to the wire when it comes to supply matching demand. It's not a new thing and has been a issue since I worked in the Power Generation Industry for nearly twenty years on and off from 74 -96. With the demise of coal and the increase in gas fired stations which are usually much smaller than the traditional coal fired stations, I think we are headed for trouble. We currently buy a huge chunk of the gas we use from other countries. The same for the electricity we buy from French nuclear power stations. Even before coal became a dirty word, we used to buy it in from South Africa and Russia despite there reputedly being 300years worth under our feet.

I am a big fan of renewables. Wind and solar are great but the electricity generated cannot be stored. If we have a dull day with no wind then we are screwed without there being a mix of traditional power stations on standby. That in itself is expensive. Throw 30m electric cars and electricity hungry air scourced boilers into the mix and we are up the swannie.

In my view we need to be building Nuclear powered stations and building them now. Yes they are expensive to run and create their own problems regarding the waste but we must have security of supply or we will be beholden to other nations to keep our lights on.

We also need to be ramping up the number of solar and wind farms massively.

Hi gaz97, always good to hear from fellow engineers. Tbh I was trying to keep it simple, but agree with what you say and yes I doubt the carts are anywhere near 22kw instantaneous load. But for some EV's the peak draw is 95A as its a 22kw load. The point that I was trying to convey was that for all existing electricity supplies to a premises there is a finite amount of current that can be drawn from it. The supplies being designed for the demand of the building at a time way before EV's. Once you reach full loadfrom it, your into switching loads between banks of EV's chargers and timed charging solutions or upgrading the capacity.

Heres an example where UKPN, installed a smart time monitored system and local battery storage to facilitate charging of more UPS EV trucks at one of their London hubs, As they did not want to go down the network reinforcement route. I cant help but think that for 170 odd vehicles thats some battery bank!

https://www.ukpowernetworksservices.co. ... -electric/

With regard to UK demand as a whole, I totally agree that security of supply in the UK is more fragile than its ever been and successive governments have been ignoring the situation. When i worked in the power sector only up to a few years ago, the number of times the National grid sent out inadequate system margins was becoming more and more frequent. When the last of the remaining coal plants go off line, any peak demand will have to be met by Combine Cycle Gas Turbine set ups. As you know Dinorwig has traditionally been used as the main back up for peak loads in the UK since it opened in the early 80's but it too needs off peak power to refill the upper reservoir. Whilst I agree that new nuclear is probably our best long term solution, the fact remains that the new reactor design that EDF are building in Hinckley is the first of its type anywhere in the world. It will be over budget and have numerous teething problems as there always are with any completely new design.

Presumably the 16amp breaker was not a BSEN60898 Type C, and the inrush current at the start of the charge was tripping the breaker? Ive not fitted any EV chargers myself but I thought most were 40 - 50amp MCB's? at 16amp it must be a long charge period.

Regards Norfolk

[ssdd]

Don't know if either of you saw this video, but it's very interesting, and references some of the ideas you're both discussing.
From LTB 407/21: viewtopic.php?t=102027

Delivering a Cleaner Future with Royal Mail - Hitachi (Oct. 5, 2021)

[Norfolk 'N' Chance]

ssdd

Many thanks for the link, and NO not seen that before.

[97gaz]

Presumably the 16amp breaker was not a BSEN60898 Type C, and the inrush current at the start of the charge was tripping the breaker? Ive not fitted any EV chargers myself but I thought most were 40 - 50amp MCB's? at 16amp it must be a long charge period.

Regards Norfolk

No. It was actually a type B. Handy for me though as they didn't use that charger anymore as it kept tripping. As you say probably inrush current. Supposedly fitted by qualified sparks.They had bought a charger that plugged into a normal 13A socket. So after doing the continuity and IR tests I could only assume the trip was lazy. I disconnected the hard wired charger and borrowed the MCB for the radial circuit that was tripping. Problem solved.

You're right though. You're not going to be able to fast charge an EV on a 16A MCB. They usually charge their car overnight so less power draw. I was surprised at the size of the supply cables to the charger. Couldn't have been more that 1.5mm.

I worked for Parsons at Newcastle. Mainly building up to 660Mw two and four pole generators but spent a chunk of my summers working on stations around England. A lot of which have gone now. I spent the whole summer of 92 at Thurrock doing a stator refurb only for it to close the following year. I spent some time self employed as a spark mostly doing commercial and domestic and it wasn't unusual to come across a 60A board fuse.

[SpacePhoenix]

There's a good few HV electric cables 9the ones in the street locally that are getting towards being life expired so the DNOs are going to have to decide soon as to if it'll be like for like replacements (same capacity ) or if the new cables will have a greater capacity

[Splappy_McSplap]

I can see it now. I get in the (electric) van and turn the key to find that the guy that had it yesterday for collections and did 52 miles in it, who has also been filling it with rubbish every day and broke the window switch, hasn't bothered to charge it and left it with 8 miles range.

Oh also it takes 3 hours to charge.

[Norfolk 'N' Chance]

Presumably the 16amp breaker was not a BSEN60898 Type C, and the inrush current at the start of the charge was tripping the breaker? Ive not fitted any EV chargers myself but I thought most were 40 - 50amp MCB's? at 16amp it must be a long charge period.

Regards Norfolk

No. It was actually a type B. Handy for me though as they didn't use that charger anymore as it kept tripping. As you say probably inrush current. Supposedly fitted by qualified sparks.They had bought a charger that plugged into a normal 13A socket. So after doing the continuity and IR tests I could only assume the trip was lazy. I disconnected the hard wired charger and borrowed the MCB for the radial circuit that was tripping. Problem solved.

You're right though. You're not going to be able to fast charge an EV on a 16A MCB. They usually charge their car overnight so less power draw. I was surprised at the size of the supply cables to the charger. Couldn't have been more that 1.5mm.

I worked for Parsons at Newcastle. Mainly building up to 660Mw two and four pole generators but spent a chunk of my summers working on stations around England. A lot of which have gone now. I spent the whole summer of 92 at Thurrock doing a stator refurb only for it to close the following year. I spent some time self employed as a spark mostly doing commercial and domestic and it wasn't unusual to come across a 60A board fuse.
[/quote

Interesting career 97Gaz. I spent 27 years with a DNO in numerous roles and then a couple of years at a Nuclear station. Then up till covid I was sparking a bit and doing some design and verification work for other contractors. Some of the major UK housebuilders loved me when I would fail new build electrical installations as they were not BS7671 compliant. But then some of them were paying their labour £60 a day! But alll my leads dried up eventually, bad timing for me to move to the country just before covid and times got hard. Long spell of unemployment... Hence being at RM via the agency.

No pun intended but some of the so called qualified sparkies work is "shocking", how they get away with it i dont know! - A B type breaker.... no wonder it was tripping. You only have to look at how B6 MCB will trip at 1.5 times current on a lighting circuit, when you switch on an old 100w fillament lamp as the inrush current is well over 10amps when the lamp is cold. How is a 16AMP Type B breaker with a trip threshold of around 24/25 amps going to react when the battery load is first energized. Provided the circuit disconnection time could be met (i.e. not exceeding the max EFLI for the type of breaker), I might have tried to fit a type D. But the Zs would need to be very low, so no long cable runs..... apologies I digress.

Despite the introduction of the various self certification competency schemes for domestic sparkies, the lack of knowledge and training out there is worrying.

Certainly be interesting to see how things pan out with EV's. As a final aside, I looked at the cost of some of the 250-300Amp DC fast chargers that bypass the EV's onboard rectifier, (as thats what limits the maximum current draw when charging from AC). For a 250Amp unit, its circa £30,000!
Cant see too many of those being installed at DO's can you?

Regards Norfolk

[DB1100]

I can see it now. I get in the (electric) van and turn the key to find that the guy that had it yesterday for collections and did 52 miles in it, who has also been filling it with rubbish every day and broke the window switch, hasn't bothered to charge it and left it with 8 miles range.

Oh also it takes 3 hours to charge.

Some of the bozo's at our place can't even manage to put their scanner back properly to charge, so they've no chance of being able to charge an electric buggy without causing a blackout

[SpacePhoenix]

I can see it now. I get in the (electric) van and turn the key to find that the guy that had it yesterday for collections and did 52 miles in it, who has also been filling it with rubbish every day and broke the window switch, hasn't bothered to charge it and left it with 8 miles range.

Oh also it takes 3 hours to charge.

Some of the bozo's at our place can't even manage to put their scanner back properly to charge, so they've no chance of being able to charge an electric buggy without causing a blackout

Maybe something along the lines of:

https://www.autoexpress.co.uk/car-news/ ... cables-the

[Norfolk 'N' Chance]

I can see it now. I get in the (electric) van and turn the key to find that the guy that had it yesterday for collections and did 52 miles in it, who has also been filling it with rubbish every day and broke the window switch, hasn't bothered to charge it and left it with 8 miles range.

Oh also it takes 3 hours to charge.

Some of the bozo's at our place can't even manage to put their scanner back properly to charge, so they've no chance of being able to charge an electric buggy without causing a blackout

Maybe something along the lines of:

https://www.autoexpress.co.uk/car-news/ ... cables-the

Interesting, and in theory its up scaling of the wireless charging devices that that some cars have for some brands of mobile phones. The article doesent give any insight into the strength of the magnetic field that the embedded wireless charger needs to produce so that it can induce a current into the charger coil within the EV? and in all likelihood it wont be able to compete with fast high current DC charging via lead. Id also be interested to see what "electrical losses" exist with this system over direct copper cable coupling via a plug and socket? Similarly it may well be that more electrical energy is required by the emebdded chargers so £ for Kw it might be more expensive.

As for 100m of road with embedded wireless chargers, great idea and at that distance no doubt the test bed works ok. But how do you expand this and how practical is is to dig up every major road in the country/world to install this system? Iit also needs electrical supplies to feed into it at various points, so that will mean many new electricity substations and more infrastructure. Just look at the electrical infrastructure behind UK rail or the underground and you see its far more than the overhead catenary cables.

[POSTMAN]

Uttoxeter