Electric cars

Joe_Horner

Regardless of tech developments (current or future), EVs suffer from one insurmountable problem compared to liquid (or gas) fueled ones unless we fairly radically change our use patterns. That problem is recharging / refuelling.

No matter how you cut it, a (say) 60kWh battery pack needs to be supplied with something over 60kWh of electricity to fill it. That's the equivalent of 30 fan heaters on full heat for an hour.

At domestic mains voltage, charging in an hour (if the battery would accept it) would require about 250 Amps. Filling in, say, 10 minutes to be comparable with pumping a tank of fuel would need 6 times that, or 1500 Amps. That's roughly the maximum entire supply for 15 - 20 typical houses.

Obviously, we wouldn't be charging at those rates at home but, if we hoped to use them according to current patterns, we would need to have charging at those sort of rates at roadside charging stations.

If we don't change our use then, in order to prevent horrendous congestion, those stations would need to be able to charge as many cars as a typical filling station can handle - so let's say 10 at a time.

That leaves each station needing an electrical supply equivalent to 150 houses burning electricity until their main fuses pop. That's assuming 100% supply and charge efficiency, which isn't going to happen. And that figure doesn't change significantly as the tech develops because it's based purely on the energy transfer required.

Tech improvements may let batteries accept the energy quicker, or may increase the storage capacity of the vehicle, but that energy still needs to be transferred and the infrastructure needed to do that according to our current use is beyond massive.

Even adopting standardised battery packs that can be swapped on demand wouldn't completely solve that problem because, over time, the swapped-out batteries would need to be charged as fast as the charged ones were swapped in. That might be possible at quiet sites, but a busy "fuel" station would need that massive supply capacity or it'd run dry.

There's also a secondary problem, for those who say "you'll just have to get used to charging more slowly overnight". To have a charging point at home you really do need a garage, or at least a drive, to locate it. That effectively rules out overnight home charging for a huge chunk of the population. Got no drive? Don't expect to sell your house in a hurry....

So, yes EV may well be the future but it's going to be a future with very different vehicle use and large segments of society effectively prevented from using them at all.

silverwhistle

Regardless of tech developments (current or future), EVs suffer from one insurmountable problem compared to liquid (or gas) fueled ones unless we fairly radically change our use patterns. That problem is recharging / refuelling.

No issues with that, we'll just change our behaviour as we have done before. Infrastructure is changing already, and although it might have to be accelerated, the only real issue is one of political will and thinking strategically , as already pointed out just above.

I find threads like this useful as there are often contributions from real life users who give a good idea of the practicalities. I'm a £5k second-hand motor kind of lass, so I'm waiting for the second hand market to expand. I'm also not a commuter and the range issue for my leisure usage is still an important one, although changing with changing life circumstances. I can see a bit of (very basic) spreadsheet work coming up to determine the optimum solution, but I can envisage different combinations of meeting my mobility needs and wants, some of which may not be available now.

At the moment, for example, I do a couple of weeks in the Alps every year skiing and visiting friends with a laden car, and the same to northern England every summer to various remote places. I can't see any potential electric vehicle of mine being able to do that in the near future, but in 5 years time I may not be able to ski anyway, or they may be a far wider network of road/rail. Who knows?

Looking at the faster charging network in the south of England the other day it was noticeably sparse round Hampshire and Susex, but I can see a commercial imperative improving things. Once the well-off are in their Teslas and electric BMWs the posh country hotels will start offering charging and it will go down the market, particularly those places which are a bit far from the normal networks. A friend offered my GF and I a trip in a helicopter and in researching where to go it was interesting to see how many country hotels had pads. It'll be a similar, but faster and more extensive process for charging points.

Large supermarket chains will also get into the act: spend £30 and get a free half hour, and other marketing ploys. It's not there yet, but there are lots of strands in the way to electrifying vehicles.

Joe_Horner

silverwhistle wrote: »

No issues with that, we'll just change our behaviour as we have done before. Infrastructure is changing already, and although it might have to be accelerated, the only real issue is one of political will and thinking strategically , as already pointed out just above.

It's a little more than that in many areas.

I live in rural Wales and rely on a car for just about everything - getting to work, carrying items for work (clock collections and deliveries - usually long-case so not really bus suitable), getting to any shops except the hugely over-priced village one - again, busses not really useful with a week or fortnight shop in tow.

Besides which, public transport is dire and expensive around here and not likely to change because even if everyone in every village started using them (all needing to go in different directions) it wouldn't add up to one London route's worth of passengers.

Very few of the homes around here have drives or garages, so charging of EVs will be a huge problem with no real solution.

So, yes, political will and planning may well make it possible in towns and cities but the rest of us will get left even further behind and no amount of technological innovation in pure EVs will prevent that.

vman

janninew wrote: »

I'm a bit stumped why people buy the Leaf!

I suspect that's as much to do with Renault vs Nissan as much as Zoe vs Leaf. Renault build quality, like most French cars, is poor and the Zoe's reputation is suitably tainted. The Leaf is an odd looking fella for sure (my daughter says it looks like a cut'n'shunt - two halves of two reasonable looking but different style cars welded together). The Leaf is a better quality finish internally, and a more practical car. Slightly larger and the lack of a non-split rear seat is a bit odd IMO.

almillar

No matter how you cut it, a (say) 60kWh battery pack needs to be supplied with something over 60kWh of electricity to fill it. That's the equivalent of 30 fan heaters on full heat for an hour.

I think I can safely say I do around 3.5-4miles per kWh in my Zoe. If I had a 60kWh battery, a full charge would get me a solid 210 miles. My point being, with the increases in capacity, people won't have to charge as often as some think. Once every 1-2 weeks for me, and if that's overnight at home (at my 7kW charger), it helps flatten out demand. We'll be left with public charging being for long trips and people who don't have home chargers.

These big charging areas (10 'pumps') would need to have storage (you know, those old car batteries!) and also smart chargers, that can slow down charging if needed in response to demand on the grid.

At domestic mains voltage, charging in an hour (if the battery would accept it) would require about 250 Amps

About the best that most homes can do, with their single phase AC, is 7kW.

Obviously, we wouldn't be charging at those rates at home but, if we hoped to use them according to current patterns, we would need to have charging at those sort of rates at roadside charging stations.

Stop for a coffee, lunch, pee break? You've got a 200 mile range now, remember. 10 minutes would fly by. 30 mins will take a Leaf to 80% as it is now. 10 mins is very fast/demanding.

If we don't change our use then

That's the problem. We DO change our use. When's the last time you put diesel/petrol in your car in your own driveway?!

That effectively rules out overnight home charging for a huge chunk of the population

Nope, street light chargers would help many, but certainly not all.

You make me think of the massive infrastructure we already have in electricity, and in petrol stations. The petrol stations have to store massive amounts of liquid underground to pump into cars, and big lorries have to carry the liquid into them. Imagine if the 'fuel' could be pumped in via 'wires' and stored in batteries, where the liquid used to be stored, fill the batteries off-peak, and they help out with demand on-peak.

Imagine launching a car now, that only took 5 minutes to recharge, could go 500 miles, but involved carrying a flammable liquid underneath your children, and setting fire to it in front of you. And we had to build all these petrol stations!

Solved... (OK, sort of!)

Renault build quality, like most French cars, is poor and the Zoe's reputation is suitably tainted

Nope. Any stats to tell us Zoes are more unreliable than other electric cars? I'll accept that the interior isn't as nice, and it isn't as fast as an i3, but it's also half the price.

The Leaf is a better quality finish internally, and a more practical car.

Accepted.

silverwhistle

Joe_Horner wrote: »

It's a little more than that in many areas.

I live in rural Wales and rely on a car /SNIP/

Oh yes, and as I pointed out the current network of charging points in Hanmpshire and Sussex is poor. It will improve here before it does in Wales, just as I imagine most rural areas were behind in the introduction of petrol stations for the new fangled cars when they replaced pony and traps.

But what is your actual daily mileage, and won't increasing ranges open up the market even to people like yourself? It's worthwhile pointing out issues, but they aren't all going to be addressed at once.

I certainly wouldn't want to go touring in Wales in an electric car, so perhaps the Welsh tourist office might help in these first, baby steps.

Keep_pedalling

Rapid charging may not be the only option.

https://www.youtube.com/watch?v=H5V0vL3nnHY

AdrianC

silverwhistle wrote: »

just as I imagine most rural areas were behind in the introduction of petrol stations for the new fangled cars when they replaced pony and traps.

Not really - in the very early days of motoring, fuel was sold in sealed, branded cans - often by chemists, blacksmiths or coaching inns.

The problem with rural charging infrastructure is not so much the installation of charging points, but that the National Grid simply does not have the capacity to support them, even if the generation capacity was in place - which it isn't. Upgrading those will be a VERY expensive and involved long-term project. There's a legacy of short-termism.

A fine example: I live in a corner of a very sprawling, rural village (120 houses across 15 km2). There are seven houses and a small farm in relatively close proximity here, all served by a single transformer. That transformer is on my land, right behind where we built a garage a few years ago. Western Power were involved at the time, and decided to take the opportunity to replace the transformer, together with the poles it was on. They replaced the existing goal-post mounted 1960s 200A-fused, 300A-rated single-phase transformer with... a pole-mounted 200A-fused, 300A-rated single-phase transformer. It's not that three-phase wasn't an option - all three 11kV conductors come across the valley to us, the third untapped. Changing that transformer now will be much more difficult than it was then. The farm's supply was simultaneously moved from overhead to underground. Single-phase cable was laid...

AdrianC

Keep_pedalling wrote: »

Rapid charging may not be the only option.

https://www.youtube.com/watch?v=H5V0vL3nnHY

BetterPlace were the people who were pitching battery-swapping. They went bankrupt in 2013, around the same time as that video. Nobody's really brought the idea back.

You'd need to have a substantial stock of spare batteries on charge at any given time, in a range of standardised sizes, common across the entire industry. The pack on a Model S basically fills the entire floorpan, and is shaped to fit. Yes, you could use smaller, modular packs - 1 in a Twizy, 2 in a leaf, 3 in a Model S - but you'd be wasting a lot of packaging space, and losing range. You'd need to have those batteries owned by a recharge-swap network, and leased. You would need monumental cabling to that recharge-swap station.

silverwhistle

AdrianC wrote: »

A fine example: I live in a corner of a very sprawling, rural village (120 houses across 15 km2). There are seven houses and a small farm in relatively close proximity here, all served by a single transformer.

This reminds me of a social chat with a distribution engineer colleague probably mid to late 80s: he was lamenting the cost of upgrading a sub-station for an expanding housing estate. He was only half-joking when he said 'it would be cheaper to give them all CFL bulbs'.

I don't know when your transformer was replaced but even a couple of years ago peak loads were coming down as LED bulbs and more efficient TVs, appliances and computing came in. Electric cars were a very distant future.

You're right about short-termism generally in this country but I wonder how the reinforcement guidelines are changing now?

It sounds like a few domestic solar panel installations wouldn't go amiss to reinforce your local network, although if it's in Wales I can understand from my experience of the weather why they aren't there.