EV range, in car value and actual
Discussion
I have a Renault 4 with 52 kWh battery. Anyway I did a calculation for my regular drive to the ice rink. I used the in car value for the average miles per kWh and the distance to calculate and equivalent range on a full battery. I then used the charge used, which is known as after the journey it was charged to the pre-journey level i.e. 80%, and the distance to calculate the full range. Note that aircon was deliberately turned off, but the radio or CarPlay was on, and it was a daylight journey so road lights were off, DRLs were on.
15 October 51.5 miles driven.
In car usage 5.8 mpkWh. => 5.8 x 52 ??=? 301.6 miles.
Car received 10.15 kWh. => 51.5 X 52 / 10.15 ??=? 263.842 miles.
As you can see the difference is quite large. Why is this?
My VW Polo average consumption displayed in the car overestimated mpg by about 5%.
15 October 51.5 miles driven.
In car usage 5.8 mpkWh. => 5.8 x 52 ??=? 301.6 miles.
Car received 10.15 kWh. => 51.5 X 52 / 10.15 ??=? 263.842 miles.
As you can see the difference is quite large. Why is this?
My VW Polo average consumption displayed in the car overestimated mpg by about 5%.
Edited by Renault4 on Sunday 18th October 12:12
TheDrownedApe said:
Regen.
Energy loss from charging is 5-15%
Probably more factors too
AC charging at home can be more than that, I've lost over 20% on my EV when it's cold; DC charging losses are very small IME.Energy loss from charging is 5-15%
Probably more factors too
I think the 5.8 m/kWh is most likely a bit too good. Is it all usage, or just that consumed by the motors? The lights would have negligible effect, all being LEDs I expect.
sixor8 said:
AC charging at home can be more than that, I've lost over 20% on my EV when it's cold; DC charging losses are very small IME.
I think the 5.8 m/kWh is most likely a bit too good. Is it all usage, or just that consumed by the motors? The lights would have negligible effect, all being LEDs I expect.
Exactly, what is being presented to us?I think the 5.8 m/kWh is most likely a bit too good. Is it all usage, or just that consumed by the motors? The lights would have negligible effect, all being LEDs I expect.
Yesterday, the charger supplied 21.9 kWh, the battery received 20.65 kWh, so there is a roughly 7% loss on charging the battery. However, in my calculation in my original post, the 10.15 kWh added is the amount added to the battery, not the amount provided by the charger, so it excludes charging losses.
When I'm doing calculations (Tesla Model 3) my assumption is that the charger only knows what it's given and not what's been lost and the car only knows what it's taken and not what's been lost.
So when I'm working out what the charge has cost me I work from the numbers on the charger and when I'm working out the efficiency of the car I work from the number in car.
So when I'm working out what the charge has cost me I work from the numbers on the charger and when I'm working out the efficiency of the car I work from the number in car.
TUS373 said:
I have never got any where near 5.8 miles/kW. More like 4.5 tops, in real world driving.
It’s very dependent on driving style, your value sounds right for normal driving, I could almost always get better than the WLTP value for my petrol VW Polo, by using low revs where engines are more efficient. As an aside, the American chap who first flew across the Atlantic taught US militwry pilots how to extend their range using low revs. I've done some maths on my car (not a Renault though) and the % charged/used doesn't align to real battery capacity. Also power in Vs power in battery Vs claimed mpkwh don't match for a large percent of battery power until it's low. From the op earlier comment I think 10kw to the charger Vs say 9kw used or 90% power into charger to wheel isn't bad.
It's not just charging efficiency losses within the battery, either. When the car is charging, at least some of it's computers are up and running, and they consume energy too. This is partly why you see better efficiency with a faster charger - the computers need the same power whether you're feeding the car 2kW from a granny charger, or 250kW from a high speed DC charger - but that power is obviously a much larger proportion of only 2kW.
I have tracked everything from day 1 and just passed 10k miles in 6.5 months in my R5. The "true" miles/kWh is 3.55 inclusive of charging losses. Actual kW received by the car tracks at 97.5% charging efficiency. This has been 88% home charged so interested to read how much less efficient others experiences are with AC charging. Maybe my Pod Point is really efficient? I think the greatest loss I have seen so far was 4.5% on a single charge. Take losses out the equation and my efficiency increases to 3.6m/kWh. As others have said the faster charge is more efficient even though you would assume more losses due to heat etc. Granny charging is the least efficient method due to keeping the car computers etc on for a much longer period.
The consumption recorded by the car has never been reset from pickup and shows 4.1m/kWh. I believe this is the efficiency of the motor being reported and does not take into account all the further losses through the drivetrain. I do significant motorway miles and drive it like an ICE. Cabin heating/cooling is always on and I am never doing less than 70 on the motorway. For what it is it's exactly what I expected. I can comfortably do 150 miles a time, leave with 100% and this will take it down to approximately 20%. By then I am at my destination or needing the toilet anyway so it's not been a problem. I am intrigued to see how much further this takes a beating in the depths of winter.
I see every EV as no different to ICE. Whatever a manufacture claims (m/kWh or mpg) take 75% of it and it's roughly the real world expectation.
The consumption recorded by the car has never been reset from pickup and shows 4.1m/kWh. I believe this is the efficiency of the motor being reported and does not take into account all the further losses through the drivetrain. I do significant motorway miles and drive it like an ICE. Cabin heating/cooling is always on and I am never doing less than 70 on the motorway. For what it is it's exactly what I expected. I can comfortably do 150 miles a time, leave with 100% and this will take it down to approximately 20%. By then I am at my destination or needing the toilet anyway so it's not been a problem. I am intrigued to see how much further this takes a beating in the depths of winter.
I see every EV as no different to ICE. Whatever a manufacture claims (m/kWh or mpg) take 75% of it and it's roughly the real world expectation.
Edited by Goatwidcoat on Monday 19th October 06:32
Out of interest did everyone track their mpg in ICE cars? I used to get 225 miles from a tank costing £70 (probably nearer £100 now) and get about 200 miles from a full battery costing c€3. I know which would bother me the most.
Admittedly at €0.0418 all in per kWh I’m not exactly worried by how much electricity I use.
Admittedly at €0.0418 all in per kWh I’m not exactly worried by how much electricity I use.
Opapayer said:
Out of interest did everyone track their mpg in ICE cars? I used to get 225 miles from a tank costing £70 (probably nearer £100 now) and get about 200 miles from a full battery costing c 3. I know which would bother me the most.
Admittedly at 0.0418 all in per kWh I m not exactly worried by how much electricity I use.
Yep I've done it for the last 12 years and 210k miles of driving and I can't stop haha. It's painful to see I have spent £35k in petrol over that time. That's 1.3 million miles in my Renault 5 at its current rate! Currently averaging 2.7p/mile even with 12% being expensive public charging. My C63 was the worst at 35p/mile average and it could easily get 50p+ with your foot down. That was a 66 litre tank you could get the petrol light at 175 miles. My Integra Type R is averaging 27p per mile and that includes around 15 track days. Not too bad at all for what it is.Admittedly at 0.0418 all in per kWh I m not exactly worried by how much electricity I use.
An EV is so cheap to run I don't even think about it. We still have our two ICE cars but already done 10k in 6.5 months and saved £2k on petrol (based on an average 23p mile). It should probably be upped to 25p now but I'm not looking to track it exactly, just a rough feel for it.
Edited by Goatwidcoat on Monday 19th October 08:59
In my Honda eNy1, I wondered if the declared efficiency included all use and not just driving the wheels, but found out it does. If I leave the efficiency displaying (mine shows current and previous journey) from start at home, I have to stop at lights after about 1 mile. The efficiency can be seen to drop when stationary with other systems running. I would suggest this is the case with all EVs, but may not be. It exaggerates the efficiency a little too IME, although it may be a rounding error, it only goes to 1 digital place, ie 3.6 m / kWh.
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