Electric Vehicles: What have you spotted?

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CitroJim
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Re: Electric Vehicles: What have you spotted?

Post by CitroJim »

Simon, most interesting :) Thanks for that and very informative!

Keep these posts coming please ;)

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Re: Electric Vehicles: What have you spotted?

Post by RichardW »

Mandrake wrote:The article then goes on to conflate a "shift to electric heating" in the home with demand from EV's - where ? I don't see anyone rushing to switch to electric heating as it doesn't make financial sense...
Ah, but it's there in the back ground - if HMG is to achieve the (allegedly) legally binding reduction of 80% in CO2 output by 2050, then all heating and cooking will have to go electric. Now that really will screw up the grid and the generating capacity!

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Re: Electric Vehicles: What have you spotted?

Post by Mandrake »

RichardW wrote:
28 Sep 2017, 12:30
Mandrake wrote:The article then goes on to conflate a "shift to electric heating" in the home with demand from EV's - where ? I don't see anyone rushing to switch to electric heating as it doesn't make financial sense...
Ah, but it's there in the back ground - if HMG is to achieve the (allegedly) legally binding reduction of 80% in CO2 output by 2050, then all heating and cooking will have to go electric. Now that really will screw up the grid and the generating capacity!

Indeed, I'm not sure what the solution for home heating will be. Somewhere like New Zealand where there is no residential piped gas supply and the winters are much milder, most people get by with a minimal amount of electric heating in the winter, (I sometimes didn't use any, or maybe for only a week in the middle of winter!) or sometimes use one of those portable gas heaters in one room on the odd occasion, but not on a daily basis.

But here in the UK we are very dependent on gas central heating for the winters...and fortunately or unfortunately depending on how you look at it, natural gas is stupidly cheap compared to electricity, but that can't last forever.

I think eventually once most generation is renewable the cost per kWh will come down a lot and be more comparable to gas (since renewable is trending sharply downwards in cost to install and cost / kWh) and if there is to be any nationwide adoption of electric central heating it will have to be of the heat pump variety, since heat pumps can be 3 to 5 times more "efficient" than resistive heating and have the added bonus that they can be reversed in summer and used as air conditioning! :) It may even be that the effectiveness of a heat pump makes up for the cost differential between gas and electricity and makes electricity cost effective. (But of course we're back to needing lots more electricity generation for heating...)

I think we're probably 30 years away from a shift away from natural gas for heating though, unless it unexpectedly runs out! CO2 agreements might be there but at the end of the day they are pieces of paper and if the alternative is that peoples homes freeze it will just be pushed back, just like we've been in contravention of existing EU pollution level agreements for years now!

I prefer not to muddy the waters of EV adoption with the looming but more distant threat of electric heating - lets cross one bridge at a time... :) Who knows - in 20 years from now renewable generation may be so pervasive and cheap that electric heating no longer presents a challenge.

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Re: Electric Vehicles: What have you spotted?

Post by CitroJim »

Renewable power should, by rights, get cheaper and cheaper once the cost of installing and commissioning it has been recoupled...

Mind you, I remember them saying that about nuclear power in the late 60s... It would be so cheap it would be barely worth metering domestic consumption...

Mandrake wrote:
28 Sep 2017, 13:06
Who knows - in 20 years from now renewable generation may be so pervasive and cheap that electric heating no longer presents a challenge.


By then climate change may well have made British winters so mild not so much heating will be needed anyway...

It's already happening. In my lifetime winters have become noticeably much more benign and mild and i don't believe I'm imagining it...

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Re: Electric Vehicles: What have you spotted?

Post by Mandrake »

Mandrake wrote:
23 Aug 2017, 10:11
At speeds of 20 and below though EV's can be remarkably quiet. I'm able to drive into our driveway without our nosy neighbour hearing us and peeking out the window - completely impossible in the Xantia. :lol:

In fact a couple of times when Sara has been home working in our garden near the driveway I've driven in and stopped on the driveway with her not noticing at all and she has been startled when the door slammed just a few metres behind her. :twisted:

Thought I would post some proof - this happens to me quite a lot at low speeds... :lol:



Despite the wide angle camera lens making it seem like I'm far back I'm only about a car length behind them when I tooted... :twisted:

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Re: Electric Vehicles: What have you spotted?

Post by CitroJim »

People are going to have to become used to this and alert to it. They will.. Natural selection and evolution will see to that ;)

Then, perhaps, they won't be quite so alarmed when in the vicinity of bicycles...

One odd thing I've noticed more and more is how used to noisy ICE vehicles most animals are. The don't turn a hair (or feather) when an ICE vehicle passes but are terrified when I pass them on a bike :?

I guess they are so used to being in the presence of thousands of ICE vehicles every day but bikes are comparatively rare in their lives...

I find the same when running. Pigeons especially fly off utterly terrified yet seem to be totally comfortable with cars and vans screaming past them in close proximity...

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Re: Electric Vehicles: What have you spotted?

Post by Mandrake »

Interesting Jim - I think it must be that with the noise they know something is coming with plenty of warning and therefore feel safe however when a silent person or vehicle sneaks up on them they get startled.

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Re: Electric Vehicles: What have you spotted?

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Mandrake wrote:
28 Sep 2017, 15:46
Interesting Jim - I think it must be that with the noise they know something is coming with plenty of warning and therefore feel safe however when a silent person or vehicle sneaks up on them they get startled.


I think you may well be right there Simon :) After all, we often get pretty startled when something sneaks up on us...

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Re: Electric Vehicles: What have you spotted?

Post by myglaren »

They are probably conditioned to expect noisy things to be benign but quiet things to be predators.

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Re: Electric Vehicles: What have you spotted?

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myglaren wrote:
28 Sep 2017, 17:37
They are probably conditioned to expect noisy things to be benign but quiet things to be predators.


Yes, in nature that would be the case... I guess me silently running toward them does look a bit threatening at a very basic instinctive level...

So. I'm a predator then :lol:

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Re: Electric Vehicles: What have you spotted?

Post by myglaren »

Grey Tesla S.

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Re: Electric Vehicles: What have you spotted?

Post by white exec »

BBC London evening news has just reported tonight on the availability of public EV rapid charging points in inner London.
As of today, there are just . . . five.
Spokesman for TfL said they intend to install an additional 75 by Christmas, and 150 by the end of 2018.
For heaven's sake, they should be installing that number PER MONTH !

Also reported that all new taxis will have to be EV from January '18. Hopefully that means BEV, and not the misleading Hybrids.

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Re: Electric Vehicles: What have you spotted?

Post by Mandrake »

white exec wrote:
02 Oct 2017, 18:54
BBC London evening news has just reported tonight on the availability of public EV rapid charging points in inner London.
As of today, there are just . . . five.
Spokesman for TfL said they intend to install an additional 75 by Christmas, and 150 by the end of 2018.
For heaven's sake, they should be installing that number PER MONTH !
I've got about 5 rapid chargers within 10 miles of me - in Motherwell. :rofl2:

However, rapid chargers are more for long journeys away from home charging, not for charging when you're shopping or parked at work for the day... For those you would generally Level 2 chargers. If you check http://plugshare.com and zoom in on central London you'll see that indeed there are only a few rapid chargers (the orange markers) but dozens if not hundreds of green ones which are Level 2.

There is an ongoing debate over on SpeakEV about the relative importance of Level 2 vs Rapid chargers, eg which should we be spending public money on, and to be honest I've seen good arguments on both sides and I don't know what the correct answer is. You can get something like 10 Level 2 chargers installed for the cost of one rapid charger, but it only charges at about 1/5th of the rate, so Level 2 chargers suit something like a park and ride or parking building where you would leave your car parked for the work day even after the charging has finished while a rapid suits something like a motorway services where you stop for a short time and people take turns to use the same unit(s) and are then on their way again.

Also as battery sizes increase the slower Level 2 chargers will become less important and perhaps obsolete as everyone (who has off street parking anyway) will be able to charge enough over night to do an entire day's commuting and errand running without requiring any public charging during the day. Even on my tiny 60 mile range Ion I don't make use of Level 2 chargers at all - I just charge at home and have enough to get through my day without other charging. I think I've used my Level 2 charging cable about 4 times since I've had the car - and only because I felt like testing it, not because I really needed it.

Rapid chargers I will use on a longer trip like a recent trip to Edinburgh zoo and back, or if I've done a lot of driving on the weekend and I really need to go out again less than a few hours later and do a lot of miles again, then I'll call in at the nearest Rapid charger for 20 minutes and get topped back up to 80% again quickly then go home and plug in to get a little bit more on top of that until I'm ready to head out again. But if I had 120 miles of range instead of 60 I wouldn't even need to do this. I think 120 miles would cover every conceivable daily use I have for a car at the moment from home charging besides an occasional long trip away from home where I would use a rapid charger to top up.
Also reported that all new taxis will have to be EV from January '18. Hopefully that means BEV, and not the misleading Hybrids.

I suspect they'll be Hybrids like the new EV black cabs recently announced.

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Re: Electric Vehicles: What have you spotted?

Post by CitroJim »

Is it better for the health and life-expectancy of the battery to only rapid-charge when you really have to and at all other times use a slower, more gentle charging regime?

Or, with such sophisticated battery management does it not matter?

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Re: Electric Vehicles: What have you spotted?

Post by Mandrake »

That is a difficult question to answer Jim, and it really depends on the specific battery chemistry and battery management of the car itself, especially temperature management/cooling.

I would say in general it is probably better and more conservative for battery longevity to charge a car at 3.6-7.2kW (typical Level 2 charge including home charging) instead of 30-50kW which is typical for Chademo or CCS rapid chargers, but the difference may be pretty small, and there are some confounding factors.

If you have a 30kWh battery and you charge it at 43kW (typical Chademo speed) that is only a 1.4C rate - and that's not a particularly taxing charge rate for a Lithium Ion battery as long as it is kept cool. If it was a 60kWh battery it would be below 1C and even less taxing.

The main issue is heat generation in the cells and allowing the cells to get out of their comfortable temperature range while charging - especially if they are already quite hot from fast motorway driving just prior to the rapid charge. This is where the different cars are wildly different....

For example Nissan Leaf - NO active battery temperature management system at all! Even in the new 2018 release, which is disappointing. It probably has an extractor fan for the battery housing to at least circulate fresh air through, but it does not use the A/C to cool the batteries nor does it have any sort of liquid cooling. So if you drive a Leaf hard on the motorway then rapid charge the already hot batteries it will throttle the charge rate back to keep them from getting too hot. There is even a battery temperature gauge on the dashboard, so clearly they thought it could be an issue!

Next step up is what my Ion does. It also does not have liquid cooled batteries, and while you are driving it can only cool the batteries using an extractor fan drawing in outside air - so it also has limited control over the battery temperature while driving. However when you rapid charge the Ion/C-Zero/i-Miev it very cleverly puts the A/C on and a flap automatically diverts the air from the A/C to the battery enclosure instead of the cabin.

Essentially it blasts A/C cooled air through the battery pack while rapid charging! :D It always seems to run the blower fan at full speed when it does this (even when it's quite cold outside) however I have observed that it varies the A/C compressor speed and duty cycle depending on battery temperature - in cold conditions it doesn't run much and in hot conditions it runs the compressor a lot more. So this way it is able to regulate the battery temperature quite well during rapid charging and keep it below a safe temperature. It doesn't have any way to warm the battery in really cold sub zero conditions though, other than the heat from within the batteries due to charging.

So in terms of rapid charging the Ion is superior to the Leaf for battery longevity thanks to active control of the battery temperature with the A/C

The best system is full liquid cooling where there is a water/glycol loop that weaves its way in between all the cells in the pack coming into direct contact with them - this was used first by Tesla (with the loop being somewhat like an inflated flat firemans hose between the round cells) and is also used in the Chevy Bolt.

These systems can take away a lot of heat very easily and allow very rapid charging while still keeping the battery temperature in the optimal range. The heat is taken away by the glycol loop to a standard radiator up the front - which usually also cools the motor, drive inverter and onboard charger.

Another advantage of liquid cooled battery temperature management is they usually also allow the battery to be heated when the weather is subzero. It turns out that in really cold conditions (well below zero) Lithium Ion batteries have reduced output and capacity and it is actually more efficient to spend some power to heat the battery up than just put up with the reduced output. Also you can't charge quickly at well below freezing temperatures as there is a risk of lithium plating and dendrite formation.

So trying to charge at -10 without temperature management you would have to start at a very low rate and wait for the battery to warm a bit through resistance and then as it warms up you can start to ramp up the speed and it becomes self sustaining. With active temperature management you simply heat the battery first before charging. I believe when you supercharge a Tesla in really cold temperatures it first uses the power of the charger to run the battery heater element to warm the battery before it begins charging!

So how much you affect the lifetime of a battery depends largely on how well you control the temperature during charging. Another factor is that rapid charging is usually only to 80 or 90% whereas Level 2 charging you will go to 100%. Having a battery sit at 100% unused for a long time at higher temperatures can cause degradation so if you are rapid charging only to 80% you would be avoiding this.

Unfortunately there isn't an easy answer to your question! From my perspective, I don't rapid charge my Ion unless I really need to, but when I do, I don't worry about shortening its lifetime too much as I know it has the active cooling during rapid charging.