The biggest stumbling block for EV uptake

ELM327

grogi wrote: »

Weirdly enough it is DC charger that was optional in the Leafs. Was it just a marketing gimmick then?

AC is here to stay short term for sure. AC is available everywhere...

Short term of course AC will stay.
We have a great AC 22kW network currently.

But AC comes at a cost of inefficiency - both when putting the power in and when drawing it out - and also of having to carry the extra weight of a charger.

If you have a 7kW DC charger outputting 7kW, your battery receives 7kW. If you connect to a 7kW AC charger, your car probably receives 6-6.2kW.

ELM327

KCross wrote: »

Apparently the AC components are of the order of 10kg so irrelevant in the overall weight of the car (1600+kg) so doesn't really affect range.

AC, in my mind, is required simply because thats what we all have at home (and everywhere) but if they do invent a cheap DC home charger then thats fine too.

We have AC at home, but you still need to buy an AC charger. Current cost is 400-500.

You can currently buy a chademo or CCS home charger for approx 4k. I've seen them on German sites as they have better home electricity supplies than we do.

It is more efficient to charge a DC battery via DC than AC, and if there was no possibility of home charging there would be no AC charging at all probably.

grogi

ELM327 wrote: »

Short term of course AC will stay.
We have a great AC 22kW network currently.

But AC comes at a cost of inefficiency - both when putting the power in and when drawing it out - and also of having to carry the extra weight of a charger.

If you have a 7kW DC charger outputting 7kW, your battery receives 7kW. If you connect to a 7kW AC charger, your car probably receives 6-6.2kW.

That DC charger is getting that 7 kW from somewhere, probably drawing 8 kW from AC network. Unless you plug it to medium voltage supply...

KCross

ELM327 wrote: »

But AC comes at a cost of inefficiency - both when putting the power in and when drawing it out - and also of having to carry the extra weight of a charger.

10kg is irrelevant even more so when batteries increase in capacity.

ELM327 wrote: »

If you have a 7kW DC charger outputting 7kW, your battery receives 7kW. If you connect to a 7kW AC charger, your car probably receives 6-6.2kW.

Is that really true? I have my doubts. My home charger is 90+% efficient according to the kWh meter I have on it and the LeafSpy reports. Its not 100% accurate but close enough.

On an FCP I also see the same 90% efficiency figure. When the charge session is finished it tells you how many kWh's it delivered and again LeafSpy shows you what the battery took on board.... there is a 10% loss the same as at home so I dont think you are correct on that one based on my observations.

ELM327

grogi wrote: »

That DC charger is getting that 7 kW from somewhere, probably drawing 8 kW from AC network. Unless you plug it to medium voltage supply...

Possible. But it will deliver the indicated power to the car.

KCross wrote: »

Is that really true? I have my doubts. My home charger is 90+% efficienct according to the kWh meter I have on it and the LeafSpy reports. Its not 100% accurate but close enough.

On an FCP I also see the same 90% efficiency figure. When the charge session is finished it tells you how many kWh's it delivered and again LeafSpy shows you what the battery took on board.... there is a 10% loss the same as at home so I dont think you are correct on that one based on my observations.

I have measured the AC charging versus DC charging, and I always find on leafspy that the indicated power was delivered via DC, but there were 10% losses from AC.

My curiosity (and the reason I measured it before) was because I saw it mentioned in a Bjorn Nyland video of the different losses between DC and AC charging, so I decided to measure it myself. Now I'm not an electrician but my empirical testing proved to me anyway that he was correct.

KCross

ELM327 wrote: »

I have measured the AC charging versus DC charging, and I always find on leafspy that the indicated power was delivered via DC, but there were 10% losses from AC.

My curiosity (and the reason I measured it before) was because I saw it mentioned in a Bjorn Nyland video of the different losses between DC and AC charging, so I decided to measure it myself. Now I'm not an electrician but my empirical testing proved to me anyway that he was correct.

We have different results then.

I was at the Dungarvan FCP just this weekend and it specifically showed me that it delivered 14.3kWh and I looked at LeafSpy before and after and it went from 3.3-->16kWh

So, someone/something is wrong!

To my knowledge all charging equipment is inefficient to some degree as there is heat loss. Thats why they have fans whizzing away as soon as they start. You will never get all the power delivered to the battery, there has to be inefficiency in there and it is ~90% based on what I've seen on multiple FCP's.


EDIT: I just looked at ABB's website and their latest and greatest FCP's are spec'd at 94% efficient. Bjorn was telling porkies!

liamog

We could use the heat from all the Supermarket FCPs to provide heating to the main building

ELM327

KCross wrote: »

We have different results then.

I was at the Dungarvan FCP just this weekend and it specifically showed me that it delivered 14.3kWh and I looked at LeafSpy before and after and it went from 3.3-->16kWh

So, someone/something is wrong!

To my knowledge all charging equipment is inefficient to some degree as there is heat loss. Thats why they have fans whizzing away as soon as they start. You will never get all the power delivered to the battery, there has to be inefficiency in there and it is ~90% based on what I've seen on multiple FCP's.


EDIT: I just looked at ABB's website and their latest and greatest FCP's are spec'd at 94% efficient. Bjorn was telling porkies!

But the difference is does the DC charger report the power before or after losses. I think that is where the divergence is

The fast charger shows Complete Kwh that is consumed by the charger not delivered to the car.

Leaf AC charger is a good 90% efficient.

KCross

ELM327 wrote: »

But the difference is does the DC charger report the power before or after losses. I think that is where the divergence is

What do you mean?

Its power in vs power out.... nothing else.

If it reports power after losses you are just fooling yourself into thinking there are no losses.


There are losses in the process regardless of AC or DC and they are much the same.

ELM327

KCross wrote: »

What do you mean?

Its power in vs power out.... nothing else.

If it reports power after losses you are just fooling yourself into thinking there are no losses.


There are losses in the process regardless of AC or DC and they are much the same.

My question was, of course at home I have access to before and after power figures. but do the DC chargers report power delivered to the car or power consumed by the charger? My investigations led me to the former, perhaps I disregarded the latter too quickly. Must have another look. I prefer the Efacec units as the information is easier to obtain.

jimmycrackcorm

irishgeo wrote:

you cant resell electricity anyway its against the law. so they cant charge for it.

Better tell all those camping sites that provide electricity connections for caravans...

knipex wrote:

Relatively poor people who struggle to afford 10 year old cars are having their taxes used to subsidise new cars for relatively well off people who can afford new cars.

More likely that the VRT paid on new cars is used to subsidise those people who aren't paying VRT on their older cars.

KCross

ELM327 wrote: »

My question was, of course at home I have access to before and after power figures. but do the DC chargers report power delivered to the car or power consumed by the charger? My investigations led me to the former, perhaps I disregarded the latter too quickly. Must have another look. I prefer the Efacec units as the information is easier to obtain.

Based on what I saw, they report power consumed by the charger.

You then check the before and after figures in LeafSpy to get your efficiency figure.

Its the same process when doing it at home on AC. You have a kWh meter on the power in line of the charge point so you know what is consumed and then check the before/after figures in Leafpsy to get your efficiency. There is only a few % points in the difference.

Put another way, if you bought a DC charger today and installed it at home every kWh you put into it would not be delivered to the battery. You would have to pay for that 94% efficiency figure so you wouldn't gain (or at least much) by having a DC vs AC charger.

My understanding is that DC exists because you can deliver larger currents easier rather than it being more efficient per se.

We need to call on our resident power electronics engineer..... @BoatMad!?

liamog

Deleted User wrote: »

Why would you do that ? if you have a 100 Kwh batter for instance, why wait a couple of days to let the battery run down before charging it ?

I used to have a Sony Ericsson K850i, the phone needed to be charged every 3/4 days. I didn't charge that every night. My Galaxy S8 however needs to be charged everyday. We change our habits based on the ability of our equipment.

Having lived without home charging for 8 months, a 200km range car, and access to 2 FCPs within 10km. It's definitely doable. Home charging is not 100% required, though I think that was KCross and I getting our wires crossed.

I understand the desire for home charging, and it will def be a big part of the mix, but with longer range cars and a commercial infrastructure it's a want rather than a need.

Glinda

When I looked in to this (admittedly a few years ago), I was put off by the fact that the cost to me of the battery was greater than the amount I was spending monthly on fuel. This was separate to the cost of electricity, it was a monthly rental cost for the battery itself. Is that still happening?

Sabre Man

Glinda wrote: »

When I looked in to this (admittedly a few years ago), I was put off by the fact that the cost to me of the battery was greater than the amount I was spending monthly on fuel. This was separate to the cost of electricity, it was a monthly rental cost for the battery itself. Is that still happening?

I presume that was the Renault Zoe. You can now buy a new Zoe with the battery included.

unkel

And I don't think battery lease is even an option on any other EV you can buy new in Ireland these days

It made (a bit of) sense back in the day when the lifespan of a battery was uncertain and replacing the battery would have nearly been as expensive as replacing the whole car. But the monthly rental for most people completely wasted any fuel saving people had and the Zoe / Fluence weren't even particularly cheap to buy. Battery rental: good riddance!

uphillonly

Much as we EV drivers love the free chargers, they are holding back expansion of the network. ESB need to introduce some form of charging so that there is an incentive for commercial providers to start building a competing network. Why would you build one now if the state is providing it for free?

Before this occurs, the government should ensure they have common payment systems so we don't end up with the UK mess of having multiple providers needing a different smart card for each. Imagine needing a different payment card for each petrol station brand.

On the home charging front, it's so simple & cheap once installed why wouldn't you want it with off street parking. As mentioned by others, most of us are charging from 25-50% overnight but only every few days. Home restraints & national supply shouldn't be an issue as this is increased.

Cycling through Dublin suburbs it seems well over 50% of homes do have off street parking. Huge numbers of potential EV drivers don't have the home charging hurdle. A quick google satellite view of an area like Dundrum and it looks like 80-90% of housing has off street parking. As you get closer to the centre it does change the other way with few having off street parking. Probably similar in all cities.

I'd be curious to know the % of family homes with off-street for Dublin, other cities & Ireland as a whole. ESB should have this data as part of their future EV electric demand planning & forecasts.

knipex

Deleted User wrote: »

Well if us early adopters didn't buy these new electric cars then there wouldn't be the cracking bargains available 2nd hand that there are today making them affordable to a lot more people.

You (and by that I mean not you alone Mad_Lad but all those who replied in a similar vane) are taking me up wrong.

I don't drive a new car. I have in the past but am unlikely ever to do so again. The initial depreciation, especially when doing higher mileage, is horrendous. I try and buy clean, well looked well speced 2 to 3 year old cars with low to average miles. Drive it for 2 to 3 years and then change again.

However there are a large body of tax payers out there driving <5K or sub 3K cars because that is all they can afford. They are struggling to pay road tax, insurance, fuel costs etc while also getting creamed on childcare, some (many) still in negative equity on their homes.

At the same time you have the government put under pressure to increase spending dramatically on health and housing, there is a requirement for massive capital investment in out water infrastructure, cries for investment in transport, broadband and multiple other areas and the "squeezed middle" are looking for tax cuts and the unions looking for "pay restoration" and an end to a lower pay grades paid to recent entrants..

Now the government cannot do all that.. Its impossible.. so they have a disgruntled electorate shouting louder and an element of the harder left telling them they can have it all.

Now do you want to be the politician that tells the person driving the 2K car, that not only are they putting up tax on traditional petrol and diesel cars making their life even harder but they are putting millions into VRT rebates, free home chargers and a charging infrastructure as well as free fast charging for those that can afford to spend 30K on a new car. Especially when certain elements of the media (and particularly social media) use pictures of the €100K teslas etc to slant their stories ??

knipex

unkel wrote: »

Yes there is. Home charging really isn't 100% needed anymore and hopefully becoming less so soon enough. Lidl have started to install fast charging points at their supermarkets, free for customers to use. Park, hook up, do your 20-25 minutes shop and come back to a fully charged car. No need to bother with home charging

There are over 100 free fast chargers in the EU (excellent quality triple head ABB chargers, these are better than the efaced triple head chargers the ESB have in Ireland). The first Irish one was installed and fully operational last month. Hopefully many more will follow and many more other commercial entities will follow Lidl's lead

How do you marry this comment with the earlier argument that the increased demand due to large scale uptake of EVs will not impact on grid capacity as the extra load will be during off pea hours ??

knipex

ELM327 wrote: »

Possible. But it will deliver the indicated power to the car.



I have measured the AC charging versus DC charging, and I always find on leafspy that the indicated power was delivered via DC, but there were 10% losses from AC.

My curiosity (and the reason I measured it before) was because I saw it mentioned in a Bjorn Nyland video of the different losses between DC and AC charging, so I decided to measure it myself. Now I'm not an electrician but my empirical testing proved to me anyway that he was correct.

For various reasons we are never going to have a DC transmission grid (well not in the next 50 years) so you losses will occur either in the AC to DC convert in the charger or in the car. Either way the losses remain the same..

knipex

jimmycrackcorm wrote: »

Better tell all those camping sites that provide electricity connections for caravans...



More likely that the VRT paid on new cars is used to subsidise those people who aren't paying VRT on their older cars.

VRT was paid on their older cars.. When it came into the country either new or second hand, when a car is resold that VRT is included when calculating depreciation on the retail price..

Sabre Man

knipex wrote: »

Now do you want to be the politician that tells the person driving the 2K car, that not only are they putting up tax on traditional petrol and diesel cars making their life even harder but they are putting millions into VRT rebates, free home chargers and a charging infrastructure as well as free fast charging for those that can afford to spend 30K on a new car. Especially when certain elements of the media (and particularly social media) use pictures of the €100K teslas etc to slant their stories ??

I think higher VRT + road tax based on pollution (CO2 and NOx) on new petrol and diesel cars is the way to go.

grogi

Sabre Man wrote: »

I think higher VRT + road tax based on pollution (CO2 and NOx) on new petrol and diesel cars is the way to go.

Carbon dioxide, by definition, is not pollution. However it is an excellent metric for vehicle efficiency. NOₓ is a different story, but all new cars comply with current Euro emission norms, which limits the NOₓ significantly.

The more effective solution is arbitrarily setting different VRT scale for diesels, petrols, LPG+Petrol hybrids, petrol/electric hybrids and electrics.

ELM327

knipex wrote: »

For various reasons we are never going to have a DC transmission grid (well not in the next 50 years) so you losses will occur either in the AC to DC convert in the charger or in the car. Either way the losses remain the same..

I was never stating we should have a DC grid

Power comes in in AC to the house.
We then convert it to DC at the charger and send it to the DC battery.
The DC battery sends it to the AC motor.

There's a lot of losses there. And yes, whether the charger is onboard or off board there are the same losses. So therefore it does not make sense to carry around the AC charger onboard.

knipex

Sabre Man wrote: »

I think higher VRT + road tax based on pollution (CO2 and NOx) on new petrol and diesel cars is the way to go.

Higher VRT and road tax on new cars, sure but do remember the last time the government tried to be radical with their VRT and motor tax system in 2008 ???

grogi

knipex wrote: »

Higher VRT and road tax on new cars, sure but do remember the last time the government tried to be radical with their VRT and motor tax system in 2008 ???

The changes were very effective, weren't they?

To improve is to change. We won't improve if we don't change. We will make mistakes in the process (aka 2008 fiasco), but that should not stop us changing. Acknowledge the errors and fix them.

knipex

ELM327 wrote: »

I was never stating we should have a DC grid

Power comes in in AC to the house.
We then convert it to DC at the charger and send it to the DC battery.
The DC battery sends it to the AC motor.

There's a lot of losses there. And yes, whether the charger is onboard or off board there are the same losses. So therefore it does not make sense to carry around the AC charger onboard.

It does is you ever need to charge off an AC supply.. (granny leads etc)

As said the weight on an on-board convertor is about 10kg which is pretty insignificant in the overall scheme of things. I would also be surprised if at least part of the AC to DC conversion circuitry is not also used to convent the DC back to AC.

grogi

knipex wrote: »

It does is you ever need to charge off an AC supply.. (granny leads etc)

As said the weight on an on-board convertor is about 10kg which is pretty insignificant in the overall scheme of things. I would also be surprised if at least part of the AC to DC conversion circuitry is not also used to convent the DC back to AC.

Well, we could have the AC-DC converter integrated into granny cable. You want to save weight, leave it behind. You regularly use it - keep it in the boot.

Sabre Man

grogi wrote: »

NOₓ is a different story, but all new cars comply with current Euro emission norms, which limits the NOₓ significantly.

Perhaps in ideal lab tests, but during real world driving? I wouldn't bet on it.