Battery Electric Vehicle News / Enjoying the Transportation Revolution

ABrass

Petriix said:

ABrass said:

QrizB said:

Grumpy_chap said:

QrizB said:

Exactly the same way it supports a 10.8kW electric shower? 11kW is less than 50A of single-phase 230VAC.

That's a lot for a shower.

Domestic single phase circuits can only provide 32 Amp, which is where the 7.4 kW car charger comes from.  Can't get 11kW in my house.
https://www.spiritenergy.co.uk/kb-ev-understanding-electric-car-charging

It's a lot for a shower, but it's a standard bit of domestic electrical equipment.

If you can have a 50A shower, it's clearly not true to claim that "Domestic single phase circuits can only provide 32 amp".

Some electric cookers need more than that, if you need more examples.

Yeah, you can get 40A out of a consumer unit. My cooker is rated for 11kW. You can find 40A chargers as well, although they're more expensive. The problem is no one needs it.

If you think about it it's obvious, if you need to charge a battery then the difference in time between a 7kW charger and an 11kW charger is a one third reduction in time, that's not much when you factor in time spent asleep. For you to get any benefit out of it you have to need to charge your battery faster than a 7kW charger can do it, but you're not in enough of a rush to need a 250kW charger.

If you have 12 hours down time for charging then you can essentially fill a 100kWh battery every day on 7kW. That's at least 200 miles, more like 300+. You need to use huge amounts of power and have slightly restricted charging time for the 11kW to have a  advantage. 

11kW charging is 3 phases at 3.6kW each. 

At 7kW, 100kWh (in your example) would take over 14 hours. At 11kW it's just over 9 hours. It's conceivable that someone might drive 250 miles each day and only have 8 hours at home. 

But they only just drive 250 miles a day, no more. Because if it's more then they're charging during the day too. It is a very narrow window with very few people living in it.

shinytop

Petriix said:

ABrass said:

QrizB said:

Grumpy_chap said:

QrizB said:

Exactly the same way it supports a 10.8kW electric shower? 11kW is less than 50A of single-phase 230VAC.

That's a lot for a shower.

Domestic single phase circuits can only provide 32 Amp, which is where the 7.4 kW car charger comes from.  Can't get 11kW in my house.
https://www.spiritenergy.co.uk/kb-ev-understanding-electric-car-charging

It's a lot for a shower, but it's a standard bit of domestic electrical equipment.

If you can have a 50A shower, it's clearly not true to claim that "Domestic single phase circuits can only provide 32 amp".

Some electric cookers need more than that, if you need more examples.

Yeah, you can get 40A out of a consumer unit. My cooker is rated for 11kW. You can find 40A chargers as well, although they're more expensive. The problem is no one needs it.

If you think about it it's obvious, if you need to charge a battery then the difference in time between a 7kW charger and an 11kW charger is a one third reduction in time, that's not much when you factor in time spent asleep. For you to get any benefit out of it you have to need to charge your battery faster than a 7kW charger can do it, but you're not in enough of a rush to need a 250kW charger.

If you have 12 hours down time for charging then you can essentially fill a 100kWh battery every day on 7kW. That's at least 200 miles, more like 300+. You need to use huge amounts of power and have slightly restricted charging time for the 11kW to have a  advantage. 

11kW charging is 3 phases at 3.6kW each. 

At 7kW, 100kWh (in your example) would take over 14 hours. At 11kW it's just over 9 hours. It's conceivable that someone might drive 250 miles each day and only have 8 hours at home. 

I never thought of home charging time before now, only range.  Not being able to use the car for 14 hours prior to a long trip (during which I don't want to or can't easily stop for a cup of tea/charge) could be very inconvenient.  

Martyn1981

I'm genuinely baffled by the issue here about not being able to charge the BEV enough overnight. Average daily drive in the UK is about 22 miles, so overnight you can charge for a week's worth of driving.

If you are planning a long trip, then you just add more over two nights.

If you are driving very long distances every day, and can't fully charge overnight, then you'd be using the ultrafast public chargers on your journey (which reasonably, must be involving motorways).

I'm not convinced that having 100kWh battery is a good idea, unless you are using (and more importantly needing) that kind of continuous range frequently. It's additional expense and weight, when a ~50kWh and ~200mile range is reasonable. [Caveat - with a good and reliable charging infrastructure, which I appreciate is not yet the case in the UK. But if you were driving around ~50k miles pa, then the current solution would be the Tesla Supercharger network.]

Whilst I went for the larger battery pack with the TM3, that was mostly due to the fact that you also get dual motors and AWD, and I decided to go all in. I believe I've said this before on the thread, but if not - I can't justify the TM3 LR on an economical basis for my needs and use, and have never tried to. It was a fun / midlife crisis / !!!!!! / 'wow' didn't expect the shares to do that ..... purchase, and a throwback to my youth and American muscle cars. The standard range car plus supercharger network is fine, the larger battery (around 75kWh useable) is more than enough, and can be fully charged overnight at 7kW, or two nights on 7hr cheap rate. 7hrs is also enough for the 20-80% 'standard' battery charging 'policy'.


Lastly, regarding home electricity, when we were getting the charger fitted (and under consideration for a V2G trial), we had our main fuse upgraded. It was 60A, the DNO fitted a 100A fusebox, but only an 80A fuse, as they said that was policy, unless you really needed more, and since we don't have a powershower, or large heatpump, it wasn't necessary.

[Edit - Just a thought, but my car charger doesn't go through the consumer unit, it uses tails off the mains, and its own dual pole isolator. No idea if this is standard policy?]

On the larger scale, there is support for new building, especially new estates, to have 3phase installed as standard now as we move towards an all leccy future. Apparently, there is an issue with the legislation currently where DNO's are required to provide the cheapest cost option for new developments, and this will tend to be the one accepted by the developers, whereas a more robust option would provide future proofing.

[This isn't uncommon, many moons ago when I worked in environment/water/sewerage, the building standards for a new estate dictated a foul sewer diameter that was actually smaller than the required size for adoption by Dwr Cymru. So an estate could be legally built and sold, but the homeowners would later find that adoption wasn't possible, and that they would be responsible for maintenance and clearing of a system that was itself more likely to block/fail.]

EricMears

shinytop said:

I never thought of home charging time before now, only range.  Not being able to use the car for 14 hours prior to a long trip (during which I don't want to or can't easily stop for a cup of tea/charge) could be very inconvenient.  

But you shouldn't need to do it all at once (unless you have a long trip every day !).

Two nights before my last trip I charged to 85%,  used the car for a few short trips next day then charged up to 100% on last night before setting off.

When we got home, battery was down to 15%.  First night I gave it a full 5 hrs (GoFaster) when 33kWh took it up to 73%.  Used a bit next day then charged again for full 5 hrs - but only charging flat out for 2 or 3 hrs then cell balancing and reached 100% with half an hour to spare.

Grumpy_chap

Martyn1981 said:

I'm genuinely baffled by the issue here about not being able to charge the BEV enough overnight. Average daily drive in the UK is about 22 miles, so overnight you can charge for a week's worth of driving.

If you are planning a long trip, then you just add more over two nights.

If you are driving very long distances every day, and can't fully charge overnight, then you'd be using the ultrafast public chargers on your journey (which reasonably, must be involving motorways).

I'm not convinced that having 100kWh battery is a good idea, unless you are using (and more importantly needing) that kind of continuous range frequently. It's additional expense and weight, when a ~50kWh and ~200mile range is reasonable. [Caveat - with a good and reliable charging infrastructure, which I appreciate is not yet the case in the UK. But if you were driving around ~50k miles pa, then the current solution would be the Tesla Supercharger network.]

I agree with you, but this train of discussion followed on from the linked article that Tesla / Panasonic are going to launch a new battery five times the capacity of current, so 500 kWh or 2k miles range.

That then lead to the comment that a 14-hour charge at 7 kW allows you to charge 100 kWh overnight, which is about the capacity of the largest batteries currently and, at 4 miles / kWh, is 400 mile range.  Ample.

So, no need for the higher capacity battery for your EV car.  The investment needs to be making the 100 kWh battery  more compact and lighter plus increasing the efficiency of "plug to road" so that the range of 100 kWh is as much as it can be.

Martyn1981

Grumpy_chap said:

Martyn1981 said:

I'm genuinely baffled by the issue here about not being able to charge the BEV enough overnight. Average daily drive in the UK is about 22 miles, so overnight you can charge for a week's worth of driving.

If you are planning a long trip, then you just add more over two nights.

If you are driving very long distances every day, and can't fully charge overnight, then you'd be using the ultrafast public chargers on your journey (which reasonably, must be involving motorways).

I'm not convinced that having 100kWh battery is a good idea, unless you are using (and more importantly needing) that kind of continuous range frequently. It's additional expense and weight, when a ~50kWh and ~200mile range is reasonable. [Caveat - with a good and reliable charging infrastructure, which I appreciate is not yet the case in the UK. But if you were driving around ~50k miles pa, then the current solution would be the Tesla Supercharger network.]

I agree with you, but this train of discussion followed on from the linked article that Tesla / Panasonic are going to launch a new battery five times the capacity of current, so 500 kWh or 2k miles range.

That then lead to the comment that a 14-hour charge at 7 kW allows you to charge 100 kWh overnight, which is about the capacity of the largest batteries currently and, at 4 miles / kWh, is 400 mile range.  Ample.

So, no need for the higher capacity battery for your EV car.  The investment needs to be making the 100 kWh battery  more compact and lighter plus increasing the efficiency of "plug to road" so that the range of 100 kWh is as much as it can be.

But they aren't going to launch a battery pack with 5x the capacity as you suggest, they are building the 5x larger 4680 battery cells.


[Edit - Regarding efficiency and weight, I should have said that I agree entirely. The refreshed TMX has now come out, and those are big batt vehicles. I believe the new model is ~200lbs lighter than the old one. M.]

Ectophile

shinytop said:

Petriix said:

ABrass said:

QrizB said:

Grumpy_chap said:

QrizB said:

Exactly the same way it supports a 10.8kW electric shower? 11kW is less than 50A of single-phase 230VAC.

That's a lot for a shower.

Domestic single phase circuits can only provide 32 Amp, which is where the 7.4 kW car charger comes from.  Can't get 11kW in my house.
https://www.spiritenergy.co.uk/kb-ev-understanding-electric-car-charging

It's a lot for a shower, but it's a standard bit of domestic electrical equipment.

If you can have a 50A shower, it's clearly not true to claim that "Domestic single phase circuits can only provide 32 amp".

Some electric cookers need more than that, if you need more examples.

Yeah, you can get 40A out of a consumer unit. My cooker is rated for 11kW. You can find 40A chargers as well, although they're more expensive. The problem is no one needs it.

If you think about it it's obvious, if you need to charge a battery then the difference in time between a 7kW charger and an 11kW charger is a one third reduction in time, that's not much when you factor in time spent asleep. For you to get any benefit out of it you have to need to charge your battery faster than a 7kW charger can do it, but you're not in enough of a rush to need a 250kW charger.

If you have 12 hours down time for charging then you can essentially fill a 100kWh battery every day on 7kW. That's at least 200 miles, more like 300+. You need to use huge amounts of power and have slightly restricted charging time for the 11kW to have a  advantage. 

11kW charging is 3 phases at 3.6kW each. 

At 7kW, 100kWh (in your example) would take over 14 hours. At 11kW it's just over 9 hours. It's conceivable that someone might drive 250 miles each day and only have 8 hours at home. 

I never thought of home charging time before now, only range.  Not being able to use the car for 14 hours prior to a long trip (during which I don't want to or can't easily stop for a cup of tea/charge) could be very inconvenient.  

You don't have to charge for 14 hours non-stop.  If you're going on a long trip tomorrow, but need to grab something from the shops before you go, then unplug the car, pop down the shops, then plug it in again when you get back.

Petriix

Larger capacity batteries aren't all about single trip range. They can also have bigger buffers, fewer cycles and (crucially) far greater flexibility with where and when you charge.

You don't have to charge to full every day and you certainly don't have to run it to empty before charging. You can drive faster without worrying about running out and you can avoid expensive rapid charging.

I have a 52.5kWh battery and only charge to full if I'm doing a long journey. It mostly hovers around the 40-60% range with frequent short charging sessions.

shinytop

EricMears said:

shinytop said:

I never thought of home charging time before now, only range.  Not being able to use the car for 14 hours prior to a long trip (during which I don't want to or can't easily stop for a cup of tea/charge) could be very inconvenient.  

But you shouldn't need to do it all at once (unless you have a long trip every day !).

Two nights before my last trip I charged to 85%,  used the car for a few short trips next day then charged up to 100% on last night before setting off.

When we got home, battery was down to 15%.  First night I gave it a full 5 hrs (GoFaster) when 33kWh took it up to 73%.  Used a bit next day then charged again for full 5 hrs - but only charging flat out for 2 or 3 hrs then cell balancing and reached 100% with half an hour to spare.

Yes, fair point.  Not having an EV,  I'm used to letting batteries go flat, then recharging.  It does need a certain amount of forward planning and unforeseen trips aren't unknown.  I could live with it though. 

shinytop

Ectophile said:

shinytop said:

Petriix said:

ABrass said:

QrizB said:

Grumpy_chap said:

QrizB said:

Exactly the same way it supports a 10.8kW electric shower? 11kW is less than 50A of single-phase 230VAC.

That's a lot for a shower.

Domestic single phase circuits can only provide 32 Amp, which is where the 7.4 kW car charger comes from.  Can't get 11kW in my house.
https://www.spiritenergy.co.uk/kb-ev-understanding-electric-car-charging

It's a lot for a shower, but it's a standard bit of domestic electrical equipment.

If you can have a 50A shower, it's clearly not true to claim that "Domestic single phase circuits can only provide 32 amp".

Some electric cookers need more than that, if you need more examples.

Yeah, you can get 40A out of a consumer unit. My cooker is rated for 11kW. You can find 40A chargers as well, although they're more expensive. The problem is no one needs it.

If you think about it it's obvious, if you need to charge a battery then the difference in time between a 7kW charger and an 11kW charger is a one third reduction in time, that's not much when you factor in time spent asleep. For you to get any benefit out of it you have to need to charge your battery faster than a 7kW charger can do it, but you're not in enough of a rush to need a 250kW charger.

If you have 12 hours down time for charging then you can essentially fill a 100kWh battery every day on 7kW. That's at least 200 miles, more like 300+. You need to use huge amounts of power and have slightly restricted charging time for the 11kW to have a  advantage. 

11kW charging is 3 phases at 3.6kW each. 

At 7kW, 100kWh (in your example) would take over 14 hours. At 11kW it's just over 9 hours. It's conceivable that someone might drive 250 miles each day and only have 8 hours at home. 

I never thought of home charging time before now, only range.  Not being able to use the car for 14 hours prior to a long trip (during which I don't want to or can't easily stop for a cup of tea/charge) could be very inconvenient.  

You don't have to charge for 14 hours non-stop.  If you're going on a long trip tomorrow, but need to grab something from the shops before you go, then unplug the car, pop down the shops, then plug it in again when you get back.

You obviously don't know me.  More like "... unplug the car, pop down the shops, then forget to plug it in again when you get back"  Point taken though. 

This discussion confirms that, while Mrs S and I could probably manage quite easily with a single ICE car, a single EV would be much harder.