7Kw public chargers - how useful?
Discussion
rewild said:
CharlieAlphaMike said:
Mark V GTD said:
I presume one of these 32A 'Commando' outlets requires to be wired with 6mm cable direct to the consumer unit (same as a cooker circuit)?
Not necessarily. It depends how much current you're going to draw. I can change the amount of current I draw on my car. I think to as low as 6A (although I've never set it that low). 32A is the rating of the unit. Think of it as a light fitting with a max 40W lamp recommendation. That doesn't stop you from using a 25W lamp but you'd I'll advised to pop a 100W lamp in (if 100W lamps actually still exist 
).If in doubt, it's always good to speak to an electrician of course
Blue commando plugs (57mm) with 3 pins are rated for 230V single phase, and 32A, so you MUST install the sockets with wiring which can cope with that. A device with a blue plug which fits this socket can draw 32A, and signifies to anyone passing "It's totally fine for me to plug my 32A load in here!" and it should be safe for them to do so.
The colour scheme, pin count, plug housing size etc all signify different ratings. To use fit a socket which means one thing but can only cope with less is really really really really bad.
I don't disagree with the "speak to an electrician" bit.
Edited by rewild on Wednesday 27th July 15:25
This thread starts to go slightly off track when we talk about the technicalities of an installation. However, depending upon the type of cable you use and the length of the cable run, plus the type of installation (surface clipped, in a trunking/conduit etc), you could use a cable as small as 2.5mm. That would be perfectly capable of carrying the max rated load of 32A.
As I said, I'd also advise speaking to a qualified electrician if in doubt because there are many factors that determine cable size. It's not simply down to the 'load'.
Road2Ruin said:
Tesco give you a maximum park time, 1.5 hours st ours. Also you won't get 7kwh more like 3 or 4, so in your 1.5 hours you may get 6kwh in total. At today's rates that's about £1.80 or 20 miles ish. Certainly not to be sneezed at but not a deal breaker.
I was getting 6.8kwh constant this morning at my podpoint in tesco and in 1 hour, and adds 39 miles of range in that 1 hour. If I leave the car for the entire 3 hours that is allowed, I'll get around 120 miles, for free.
Max_Torque said:
The main "benefit" from a properly installed EVSE on your wall instead of a basic socket is the ability of that unit to detect ground faults and disconnect your car in that event.
This however, despite being a fundamental part of the latest electrical regulations is pretty pointless in the real world as if there is a ground fault, everything metal in your house will be live and the regs don't protect from that, so the first time you touch your taps, sink, toaster, bath, radiators or anything else you're getting shocked anyway.
Most modern cars are so well protected from corrosion that actually touching a conductive metal surface is really surprisingly hard, every thing is plastic, painted, plated or trimmed these days. My BEV is an I3, so with that's plastic bodywork and carbon tub this is doubly pointless.
I use a 32A socket and openEVSE:
https://www.openevse.com/
and have done for 7 years with no issues.
Granny chargers have built-in ground fault circuit interruption (GFCI). No different to a wall box.This however, despite being a fundamental part of the latest electrical regulations is pretty pointless in the real world as if there is a ground fault, everything metal in your house will be live and the regs don't protect from that, so the first time you touch your taps, sink, toaster, bath, radiators or anything else you're getting shocked anyway.
Most modern cars are so well protected from corrosion that actually touching a conductive metal surface is really surprisingly hard, every thing is plastic, painted, plated or trimmed these days. My BEV is an I3, so with that's plastic bodywork and carbon tub this is doubly pointless.
I use a 32A socket and openEVSE:
https://www.openevse.com/
and have done for 7 years with no issues.
The whole hardwired EVSE thing is a total racket. They are definitely not a “must have”. Properly installed commando socket (or equivalent) and a granny charger to suit works identically. It’s what I’ve been using for my (ancient by EV standards) e-golf for years with a 32A/7kW setup. Granny cable is permanently plugged into the wall, and the charge cable is kept on hose hanger, ready for use. I use the cars built-in charging scheduler which can of course control charge rate, % charge, and also be controlled remotely via an app, amongst other things.
A hardwired EVSE would not offer anything more other than looking fancier, and doubling up on the bells and whistles via its own app that the car already has from the factory.
Edited by dvs_dave on Friday 29th July 07:16
Consider it the other way... Tesla superchargers often come with overstay charges if you leave the car after it's charged. In reality, if you skipped the overstay charge, it's still bad form to be parked and not charging.
Having used a few, it's a good job they're near fast food places and the like on motorway services, because they're very quick. No good settling down to watch a movie in the cinema, only to find you need to move your car part way through. Same for shopping I guess, not much good trying something on to be reminded you need to go back to the carpark to move.
I think it makes perfect sense that it's horses for courses. The fastest chargers being where you need it quick because you're not staying, the slowest for where you're staying for a long time. I guess that's why for most there's little point putting anything faster than 7kW in at home, your car is typically there overnight, so no need to rush, or more importantly spend lots extra on hardware so it charges for 1 hr and sits for 9, instead of charging for 4 hours and sitting for 6.
Having used a few, it's a good job they're near fast food places and the like on motorway services, because they're very quick. No good settling down to watch a movie in the cinema, only to find you need to move your car part way through. Same for shopping I guess, not much good trying something on to be reminded you need to go back to the carpark to move.
I think it makes perfect sense that it's horses for courses. The fastest chargers being where you need it quick because you're not staying, the slowest for where you're staying for a long time. I guess that's why for most there's little point putting anything faster than 7kW in at home, your car is typically there overnight, so no need to rush, or more importantly spend lots extra on hardware so it charges for 1 hr and sits for 9, instead of charging for 4 hours and sitting for 6.
Mark V GTD said:
dvs_dave said:
The whole hardwired EVSE thing is a total racket. They are definitely not a “must have”.
I think the cost of them is shocking and I have no intention of going down that route, or indeed any form of home charging. I never had a petrol pump at home when I ran ICE cars!Fair point - but personally I don't consider £900 to £1,000 cheap (£200 to £300 would be more like it) - and, for me, why would I bother as there are plenty of places around with charging facilities (many of them free, albeit the slower 7Kw ones) and no further than the nearest petrol station in my case. I do very much appreciate that charging requirements are based on individual need and vehicle range - I don't drive every day and then only around 20 miles maximum (with say one longer journey a week).
Mark V GTD said:
why would I bother as there are plenty of places around with charging facilities
Because one of the best things about owning an EV is waking up every morning with a full tank, and not having to go to petrol stations to fill up any more.Of course it depends how much you value your time (vs the cost of course). If you're on an EV tariff, you're paying less than 10p per kW at home. So you'd need to be exclusively use free chargers which limits things a little. But assuming you do, if you were going to those places anyway, fair enough... but if you do more miles, and go less places outside of those miles, charging at home is a much better way of doing it.
It's different for different people, but as an example, my journey to and from work uses around 12kWh, so on a public charger I'd need to spend ~1.5 hours there. That's 1.5 hours of my day wasted. Daily. I don't do shopping, gym, garden centre etc, so couldn't tie it into those things. If my workplace had a charger it might of course be a different story, but it doesn't.
Of course it's personal for each, you're not wrong, I'm not wrong. The above is more to illustrate why I do what I do, not to say you're wrong.
Mark V GTD said:
dvs_dave said:
The whole hardwired EVSE thing is a total racket. They are definitely not a “must have”.
I think the cost of them is shocking and I have no intention of going down that route, or indeed any form of home charging. I never had a petrol pump at home when I ran ICE cars!My point is the layout required for a fancy hardwired EVSE is not necessary to do it. An appropriately rated commando socket and granny charger for a fraction of the cost does exactly the same thing.
Edited by dvs_dave on Saturday 30th July 02:32
dvs_dave said:
Granny chargers have built-in ground fault circuit interruption (GFCI). No different to a wall box.
Granny chargers do have ground fault current leakage detection but they don't necessarily have loss of ground detection. This is relatively expensive and bulky to install (extra relays and voltage sensing circuitry), and is not required for certification of a "plug in" device so most don't have it.....I think they definitely have a use in cities and built up areas where a lot of people don’t have home chargers.
I do but I’d still take advantage of the free 7kw chargers if they were tethered. But the hassle of getting a heavy 7m cable out of boot (especially if there is other stuff in there) and plugging it all in, then put it all back 30 mins later, is not worth it for 2-3kwh of free charge that would cost me less than 20p at home. Especially if it’s crap weather and cables get wet etc.
I do but I’d still take advantage of the free 7kw chargers if they were tethered. But the hassle of getting a heavy 7m cable out of boot (especially if there is other stuff in there) and plugging it all in, then put it all back 30 mins later, is not worth it for 2-3kwh of free charge that would cost me less than 20p at home. Especially if it’s crap weather and cables get wet etc.
Edited by AF07 on Saturday 30th July 12:10
Edited by AF07 on Saturday 30th July 12:56
Good point re the wet winter weather and cables - that will be a pain. Thinking ahead I have a 50Kw charger station less than ten minutes from home (tethered CCS cable) and can see it being used a lot in winter. The downside is its expensive at 57p/kw.
Edited by Mark V GTD on Sunday 31st July 10:10
Max_Torque said:
... I use a 32A socket and openEVSE:
https://www.openevse.com/
and have done for 7 years with no issues.
Interested to hear more about this Max, as I'm pondering changing to an Open EVSE setup. Been having lots of issues with my EO charger failing to charge on schedule, have discovered as a consequence that their customer support is abysmal and, as a mere "end user", I'm dismayed at how little access I have in terms of logs, settings etc.https://www.openevse.com/
and have done for 7 years with no issues.
Mark V GTD said:
Good point re the wet winter weather and cables - that will be a pain. Thinking ahead I have a 50Kw charger station less than ten minutes from home (tethered CCS cable) and can see it being used a lot in winter. The downside is its expensive at 57p/kw.
It seams that super markets have missed a trick here. They could offer free 7kwh charging and the allow you to pay for fast charging. I see the free charges near me either busy or the street one with ice Cars parked in them.such a model might boost investment.Edited by Mark V GTD on Sunday 31st July 10:10
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