EV Discussion thread

michaels

JKenH said:

MeteredOut said:

JKenH said:

MeteredOut said:

Reed_Richards said:

MeteredOut said:

..... Has anyone ever filled up with the wrong electric?

I find my car runs just as well on the 7.5p per kWh electric that comes out of my granny charger between midnight and 7 am as it does on the premium grade electricity that comes out of a premium rapid charger and which costs up to 10 times more.  So when I have to use a premium charger it's most definitely the wrong electric.

Octopus tell me I get 100% green electricity. I am a bit concerned that if some of that non-green electricity accidentally gets mixed in, that it'd lower my miles/kWh, and might even mean more regular servicing required.

Go BP or Shell every other fill up and avoid the cheap supermarket electricity. 

Seriously though you will get better m/kWh from a rapid than home charging. Markedly so in a Leaf in winter. 

Definitely.

95% of my charging has been at home at  (2.8kW DC at 7.5p/kWh) with the other 5% being at my work (7kW DC at 14p/kWh), and I've measured (or been emailed in the case of charging at work) the kW delivered versus what the kWh the car says it has received (via the EEVEE app, though this is a very blunt % added * battery size calculation).

In the case of charging at home, the losses are around 15-20%, and on the 7kW charger, nearer 10-15%. 

I suspect fast chargers will be under 10%, but at 6-12 times the cost per kWh as charging at home, I'll put up with the losses charging at home.

I do think wonder whether some EV owners who brag about their low cost per mile use actual energy usage (kW delivered to car) rather than the charge the car receives after the inverter has done its thing.

Yes, I watched a YouTube video from EVM about the cost of owning his TM3 over 4years. He reported that it had averaged 4m/kWh over his ownership and calculated his electricity cost from this without mentioning charging losses or other parasitic losses which aren’t shown on the dashboard. To be fair, he might have included these but just not mentioned them but it wasn’t clear. @Nick1961, on here, has kept a record of the electricity used to charge his M3P over the time he has owned it (I think about 3 years) and worked it out at around 3miles/kwh. I believe @Grumpy_chap is doing the same exercise. I did see a test somewhere reporting a range of accuracy among EVs but as people frequently point out you get that with ICE cars as well. My Golf reads around 3-4% optimistic on mpg. I measured this over 2 consecutive fill ups and 988 miles last year recording 53.5mpg against an indicated 55.3 mpg. 

When you are on a trip it is driving efficiency that matters most and that is what cars try to show. Total kWh to charge is more of an academic exercise to calculate cost for comparison with, say, an ICEv but if you are predominantly home charging on an EV tariff, it’s a bit academic anyway as it probably only makes 0.5p/mile difference at most. 

Edit: although I am digressing slightly I just wanted to point out that the mpg I get from my car is significantly better than the WLTP figure. It is often said that ICE cars never match their official mpg figures. Well, that used to be true under the old NEDC testing regime but WLTP figures are a lot more and in the case of the Golf, at least, are achievable in real world conditions. (See table below from HonestJohn website). My 1.0 TSI Golf is very good. The worst I have ever seen on a tank full is 48 mpg(real) which took in a 390 mile trip in subzero conditions at motorway (including M25) speeds. My long term average is an indicted 56.3 mpg (around 54.5 mpg real).

https://www.honestjohn.co.uk/realmpg/volkswagen/golf-estate-2013

I suspect use case is really key here.  Prior to getting out first leaf we had a 1.6 petrol that gave low to mid 20s mpg for our use and then a 1.9TD that gave about 30mpg and given our journey mix was 95% less than 60 mile round trip and 80% trips of less than 2 miles an EV for us was a no brainer (more so given the mechanical wear from almost exclusive cold engine journeys and more gear changes in our 10k miles per year than a motorway car would do in 100k miles). 

WE also had the advantages of home charging and being able to hold on to a pre-depreciated ICE for the 5% of longer journeys.

We have now swapped to a slightly longer range leaf for our longer journeys too but these are all leisure trips so adding 30 mins per 2 hours for charging plus the much higher cost of rapid charger electricity is not a deal breaker.

However I think the main problem with EV adoption is that no one is willing to address the elephant in the room - the consequences of climate change are so severe that we will all have to get used to less convenience and possibly more expense if we still want to have a planet suitable for human life within the lifespan of many people already alive today.

noitsnotme

I lost only approx 8% on the last 2 recent charges.  That's with a 7kW Zappi 2 at home charging a 2023 Tesla Y.

Don't know how accurate they are but the figures came from the Zappi for energy delivered and the car for energy received.

MeteredOut

Reed_Richards said:

MeteredOut said:

So either my granny charger is rubbish (it emits very little heat, so I don't know where the rest of the energy is going) or our cars measure what they receive differently.

How do you measure kWh delivered? Tapo P110 for me.

Energy that doesn't charge the battery can only go into heat, either directly or indirectly.  So if you left your car radio on, the radio speaker moves the air and the air movement eventually causes a slight heating.  But this isn't a great example because the power consumed by a car radio is pretty negligible.  If you left your lights on then the light will ultimately get absorbed and cause heating.  Of course you could shine your lights on a photocell and convert back to electricity but you won't ever really do that. 

I also use a Tapo P110 to measure energy delivered.

Nothing in my car should be consuming the energy, so maybe just different inverter efficiencies.

1961Nick

Reed_Richards said:

I've measured my charging losses at home and I get 90% of what I put in.  I wasn't trying to brag about my low costs per mile, just to complain about the high costs per mile of charging anywhere other than at home at night.

Mine's similar at 92.9% using a 7.2kWh home charger.

1961Nick

michaels said:

JKenH said:

MeteredOut said:

JKenH said:

MeteredOut said:

Reed_Richards said:

MeteredOut said:

..... Has anyone ever filled up with the wrong electric?

I find my car runs just as well on the 7.5p per kWh electric that comes out of my granny charger between midnight and 7 am as it does on the premium grade electricity that comes out of a premium rapid charger and which costs up to 10 times more.  So when I have to use a premium charger it's most definitely the wrong electric.

Octopus tell me I get 100% green electricity. I am a bit concerned that if some of that non-green electricity accidentally gets mixed in, that it'd lower my miles/kWh, and might even mean more regular servicing required.

Go BP or Shell every other fill up and avoid the cheap supermarket electricity. 

Seriously though you will get better m/kWh from a rapid than home charging. Markedly so in a Leaf in winter. 

Definitely.

95% of my charging has been at home at  (2.8kW DC at 7.5p/kWh) with the other 5% being at my work (7kW DC at 14p/kWh), and I've measured (or been emailed in the case of charging at work) the kW delivered versus what the kWh the car says it has received (via the EEVEE app, though this is a very blunt % added * battery size calculation).

In the case of charging at home, the losses are around 15-20%, and on the 7kW charger, nearer 10-15%. 

I suspect fast chargers will be under 10%, but at 6-12 times the cost per kWh as charging at home, I'll put up with the losses charging at home.

I do think wonder whether some EV owners who brag about their low cost per mile use actual energy usage (kW delivered to car) rather than the charge the car receives after the inverter has done its thing.

Yes, I watched a YouTube video from EVM about the cost of owning his TM3 over 4years. He reported that it had averaged 4m/kWh over his ownership and calculated his electricity cost from this without mentioning charging losses or other parasitic losses which aren’t shown on the dashboard. To be fair, he might have included these but just not mentioned them but it wasn’t clear. @Nick1961, on here, has kept a record of the electricity used to charge his M3P over the time he has owned it (I think about 3 years) and worked it out at around 3miles/kwh. I believe @Grumpy_chap is doing the same exercise. I did see a test somewhere reporting a range of accuracy among EVs but as people frequently point out you get that with ICE cars as well. My Golf reads around 3-4% optimistic on mpg. I measured this over 2 consecutive fill ups and 988 miles last year recording 53.5mpg against an indicated 55.3 mpg. 

When you are on a trip it is driving efficiency that matters most and that is what cars try to show. Total kWh to charge is more of an academic exercise to calculate cost for comparison with, say, an ICEv but if you are predominantly home charging on an EV tariff, it’s a bit academic anyway as it probably only makes 0.5p/mile difference at most. 

Edit: although I am digressing slightly I just wanted to point out that the mpg I get from my car is significantly better than the WLTP figure. It is often said that ICE cars never match their official mpg figures. Well, that used to be true under the old NEDC testing regime but WLTP figures are a lot more and in the case of the Golf, at least, are achievable in real world conditions. (See table below from HonestJohn website). My 1.0 TSI Golf is very good. The worst I have ever seen on a tank full is 48 mpg(real) which took in a 390 mile trip in subzero conditions at motorway (including M25) speeds. My long term average is an indicted 56.3 mpg (around 54.5 mpg real).

https://www.honestjohn.co.uk/realmpg/volkswagen/golf-estate-2013

I suspect use case is really key here.  Prior to getting out first leaf we had a 1.6 petrol that gave low to mid 20s mpg for our use and then a 1.9TD that gave about 30mpg and given our journey mix was 95% less than 60 mile round trip and 80% trips of less than 2 miles an EV for us was a no brainer (more so given the mechanical wear from almost exclusive cold engine journeys and more gear changes in our 10k miles per year than a motorway car would do in 100k miles). 

WE also had the advantages of home charging and being able to hold on to a pre-depreciated ICE for the 5% of longer journeys.

We have now swapped to a slightly longer range leaf for our longer journeys too but these are all leisure trips so adding 30 mins per 2 hours for charging plus the much higher cost of rapid charger electricity is not a deal breaker.

However I think the main problem with EV adoption is that no one is willing to address the elephant in the room - the consequences of climate change are so severe that we will all have to get used to less convenience and possibly more expense if we still want to have a planet suitable for human life within the lifespan of many people already alive today.

The figures for my car since I replaced my Rollec charger with a Zappi 17 months ago:

12,339 miles

3.59 miles/kWh according to the trip computer
3.15 miles/kWh measured form the battery
2.99 miles/kWh measured from the meter.

(The above figures are a little bit low because they represent 2 winter & 1 summer season. They will improve over the summer months.)

silverwhistle

I couldn't say what my charging efficiency is and to be honest am not too bothered. My last bill with a period on Intelligent Octopus at 15p average and then a short period on Agile at 3.23p means it's not too much of a priority on a 7kW EVSE. Occasionally I even use a granny charger in the summer when I have solar surpluses, and as I get the FIT haven't bothered with an export tariff. I appreciate the efficiency of a granny is even less but an occasional free 20 miles in the battery keeps me happy. 

1961Nick

silverwhistle said:

I couldn't say what my charging efficiency is and to be honest am not too bothered. My last bill with a period on Intelligent Octopus at 15p average and then a short period on Agile at 3.23p means it's not too much of a priority on a 7kW EVSE. Occasionally I even use a granny charger in the summer when I have solar surpluses, and as I get the FIT haven't bothered with an export tariff. I appreciate the efficiency of a granny is even less but an occasional free 20 miles in the battery keeps me happy. 

Agreed... while ever you're home charging at off peak rates then the actual cost & any small losses are insignificant. The only efficiency figure that really matters to me is the one while I'm driving the car because that determines it's range. The efficiency from the meter is interesting but pretty irrelevant @ 7.5p/kWh.  

JKenH

Perhaps it is just me, but the idea of having a charger and a channel across the pavement but no guarantee I can park outside my house would stress me out. If you are one of the first in the street to arrive home from work then possibly it would work but what if someone in your street doesn’t like EVs or takes a dislike to you personally and blocks “your” parking place regularly. Some people take these things in their stride (like the guy interviewed), but not me. Perhaps it’s because I don’t have anything else to worry about. 

EV home charging trial for drivers without off-road parking

A new trial to allow electric vehicle (EV) drivers without off-road parking to charge at home has been launched in Hartlepool.

Kerbo Charge through-pavement channels will be installed making it possible for EV drivers to take advantage of low-cost off-peak tariffs.

“Yes, you can’t guarantee a parking space in front of your home 100% of the time, but without Kerbo Charge, you can’t charge at home at all. In reality, I only need to top-up my EV once or twice a week, so it works out perfectly.”

https://www.fleetnews.co.uk/news/ev-home-charging-trial-for-drivers-without-off-road-parking

MikeJXE

JKenH said:

Perhaps it is just me, but the idea of having a charger and a channel across the pavement but no guarantee I can park outside my house would stress me out. If you are one of the first in the street to arrive home from work then possibly it would work but what if someone in your street doesn’t like EVs or takes a dislike to you personally and blocks “your” parking place regularly. Some people take these things in their stride (like the guy interviewed), but not me. Perhaps it’s because I don’t have anything else to worry about. 

EV home charging trial for drivers without off-road parking

A new trial to allow electric vehicle (EV) drivers without off-road parking to charge at home has been launched in Hartlepool.

Kerbo Charge through-pavement channels will be installed making it possible for EV drivers to take advantage of low-cost off-peak tariffs.

“Yes, you can’t guarantee a parking space in front of your home 100% of the time, but without Kerbo Charge, you can’t charge at home at all. In reality, I only need to top-up my EV once or twice a week, so it works out perfectly.”

https://www.fleetnews.co.uk/news/ev-home-charging-trial-for-drivers-without-off-road-parking

Prices start at £999

I would have thought a pole in the garden and one by the car would cost very little and do the same job but overhead ? 

Alnat1

MikeJXE said:

JKenH said:

Perhaps it is just me, but the idea of having a charger and a channel across the pavement but no guarantee I can park outside my house would stress me out. If you are one of the first in the street to arrive home from work then possibly it would work but what if someone in your street doesn’t like EVs or takes a dislike to you personally and blocks “your” parking place regularly. Some people take these things in their stride (like the guy interviewed), but not me. Perhaps it’s because I don’t have anything else to worry about. 

EV home charging trial for drivers without off-road parking

A new trial to allow electric vehicle (EV) drivers without off-road parking to charge at home has been launched in Hartlepool.

Kerbo Charge through-pavement channels will be installed making it possible for EV drivers to take advantage of low-cost off-peak tariffs.

“Yes, you can’t guarantee a parking space in front of your home 100% of the time, but without Kerbo Charge, you can’t charge at home at all. In reality, I only need to top-up my EV once or twice a week, so it works out perfectly.”

https://www.fleetnews.co.uk/news/ev-home-charging-trial-for-drivers-without-off-road-parking

Prices start at £999

I would have thought a pole in the garden and one by the car would cost very little and do the same job but overhead ? 

Many streets with older terraced houses around my area are too narrow for this to work. Cars have to park half on the pavements and this wouldn't be possible if poles were fitted by the kerb.