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Author Topic: Real life range and efficiency test in Denmark  (Read 640 times)
M
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« on: November 21, 2020, 05:16:34 PM »

You May Be Surprised: Real-Life EV Range Test Compilation By Danish Motorist Association


Ours came in second.  Wink
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« Reply #1 on: November 21, 2020, 06:14:31 PM »

"Ours"?!



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« Reply #2 on: November 21, 2020, 06:34:34 PM »

Just my own opinion, but I reckon EVs that can do 400km, 250 miles -at motorway speeds-, as some shown on this article can, represent the point where few people will worry about range.

I reckon once this is a minimum for EVs, couple with 100kW+ charging speeds, it's the end of the line for ICE cars, and the tech, if not the pricing, is clearly already there.

Jump on the motorway for 3 hours straight, half hour stop max to recharge, then another 2 hours plus of driving before the next stop, having covered over 400 miles. Who would be unhappy with that?
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JohnS
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« Reply #3 on: November 21, 2020, 06:46:51 PM »


Jump on the motorway for 3 hours straight, half hour stop max to recharge, then another 2 hours plus of driving before the next stop, having covered over 400 miles. Who would be unhappy with that?


Me.  I would be stranded 10 miles short of my daughter in Glasgow   Sad

But, seriously, I agree with you on this.
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M
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« Reply #4 on: November 22, 2020, 07:56:13 AM »


Me and Wifey. I'll suggest the TM3 LR for me, and the Ioniq 28kWh for her (both took a 2nd place), but just don't anybody tell her I said that.
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todthedog
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« Reply #5 on: November 22, 2020, 05:35:10 PM »

Denmark is very flat would be interested in results in a hilly part of the world Grin
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« Reply #6 on: November 22, 2020, 10:28:36 PM »

Denmark is very flat would be interested in results in a hilly part of the world Grin

Why would it materially alter?  What goes up (against gravity) comes down (with gravity)?

Those with better energy recovery would perhaps be better placed, but that right foot is still all important, I expect.  Tests on reasonably flat terrain are, at least, reasonably fair tests?
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« Reply #7 on: November 23, 2020, 06:37:54 AM »

My ebike goes half the distance over hilly terrain than on the flat, no regen braking, only a wrinkly peddling harder going up than along. It was a thought on the distances rather than the efficiency. Agree that the tests are fair.
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M
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« Reply #8 on: November 23, 2020, 08:16:20 AM »

Technical question here. I've been pondering energy consumption and efficiency for BEV's, but am way, way out of my league here:-

We all know that weight is important for efficiency, hence the recommendations for better fuel mileage of not carrying heavy toolboxes (etc) around in the boot unless you need them, and so on. But I was wondering if the issue is slightly less important with BEV's due to regen?

So, take two ICEV's, that are similar but one just has the driver, whilst the other has a full load of passengers and luggage. The heavy car takes more energy to get up to speed, then 'wastes' that energy through friction braking when slowing down. So additional fuel consumption. Am I right in thinking that if allowed to roll to a stop, the heavier car might go further due to increased momentum (ignoring any tyre issues for simplicity)? Also, am I right that the energy needed to maintain speed for two vehicles with the same shape and aerodynamics is the same regardless of weight (again ignoring any tyre friction/footprint issues)?

So, with a BEV's regen being around 70% efficient, does that mean that the increased energy consumption from increased weight, during acceleration is reduced by 70% so long as regen (not friction) braking is used?
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« Reply #9 on: November 23, 2020, 08:54:21 AM »

Audi were using that argument for why the Etron is so heavy - to give it better regen.
I'm not convinced - don't forget you have to accelerate that  mass in the first place, which requires more energy the heavier it is, and also the heavier the car, the more rolling resistance loss too, which is there all the time. And make more significant still when you see the size of the wheels and tyres that go on larger and larger SUVs - 21/22 inch wheels with 275mm contact patches are heavy and lossy.
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« Reply #10 on: November 23, 2020, 09:06:15 AM »

M

I think you need to develop your argument further.

Then you could convince yourself that self-charging hybrids are a good idea.   wackoold

In real life, any and every uphill downhill cycle and speed up slow down cycle will be less efficient than driving on a flat road at a steady speed. 

Remember the second law of thermodynamics.
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Countrypaul
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« Reply #11 on: November 23, 2020, 09:33:20 AM »

Technical question here. I've been pondering energy consumption and efficiency for BEV's, but am way, way out of my league here:-

We all know that weight is important for efficiency, hence the recommendations for better fuel mileage of not carrying heavy toolboxes (etc) around in the boot unless you need them, and so on. But I was wondering if the issue is slightly less important with BEV's due to regen?

So, take two ICEV's, that are similar but one just has the driver, whilst the other has a full load of passengers and luggage. The heavy car takes more energy to get up to speed, then 'wastes' that energy through friction braking when slowing down. So additional fuel consumption. Am I right in thinking that if allowed to roll to a stop, the heavier car might go further due to increased momentum (ignoring any tyre issues for simplicity)? Also, am I right that the energy needed to maintain speed for two vehicles with the same shape and aerodynamics is the same regardless of weight (again ignoring any tyre friction/footprint issues)?

So, with a BEV's regen being around 70% efficient, does that mean that the increased energy consumption from increased weight, during acceleration is reduced by 70% so long as regen (not friction) braking is used?

If the BEV is much heavier than the ICE car (which currently tends to be the case unfortunately) it will use more energy getting upto speed and the 70% recovery is on that total energy - I'm not looking at efficiency of the power provision. So a BEV just over 3 times as heavy with regen would effectivey use the same energy as a car without regen but only 1/3 the weight.

A lighter car with regen would obviously be the best option, excess weight just results in more energy being wasted whether you have regen or not, whether it is ICE or BEV.

Probably more important is what happens going round corners (which motorways tend to have few of).  A 90 degree corner could have a significant effect on energy use as the car has to decelerate in one direction but accelerate in the other. This gets beyond the physics I can remember...

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brackwell
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« Reply #12 on: November 23, 2020, 10:39:55 AM »

The friction of tyres on the road is all proportional to weight.
Going round bends increases friction.

The most efficient way to drive a car up and down hills is to never move your foot on the gas pedal.  On my ICE car i have a instant and a cumaltive power gauge and once in cornwall on the rolling hills i adopted the fixed power approach.  I got up to 80mph + at the bottom of the hills and down to 35mph at the top on some but the cumulative mpg figure was great.   This exercise can probably only be done in Cornwall in the winter as you can imagine the effect of other drivers.  To a slight degree this is how drivers subconsciously drive anyway. Put your car in cruise control and watch people slow down going up and speeding up going down hills.

So when going down hill in a EV you are loosing energy by regen unless you allow it to free wheel and store the energy as kinetic energy in an increased speed. To get max range out of a EV i think you need to freewheel when you can and at other times hold a steady power setting closely equal to a flat road setting even if that means change of speed. Best of luck with that on English roads.
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M
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« Reply #13 on: November 23, 2020, 11:52:26 AM »

Thanks for the comments, but I'm not sure they address the question, or have I missed something?
Basically, are the losses from carrying additional weight reduced* in the case of a BEV, thanks to regen getting back some of the extra energy 'burnt' during the acceleration phase? I tried to stay away from tyres, as I'm not sure whether we should include a larger tyre footprint due to increased weight, or if it should be dealt with by raising the tyre pressure as per higher weight load recommendations - basically that got way too confusing for me, but in the case of 'just a toolbox', I doubt tyre pressures would be increased so footprint should be included. Also hadn't thought about cornering, that would I assume be a loss, with no energy recovery?

*Not in any way suggesting the losses don't exist, nor that they should be ignored, just wondering if they are reduced, and if so, could it be by as much as the BEV's regen efficiency, perhaps 70%?

@JohnS - Not a clue what you are going on about. It isn't an argument, it's a request for info on the 'possible' reduction in losses. You seem to be repeating what I've said (increased losses through weight gain), whilst suggesting I might be a believer in the self charging con, rather than one of its most vocal critics.
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Just call me Mart.     Cardiff: 5.58kWp PV - (3.58kWp SE3500 + 2kWp SE2200 WNW)
brackwell
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« Reply #14 on: November 23, 2020, 12:14:53 PM »

Mart,

"Basically, are the losses from carrying additional weight reduced*"

Extra weight increases losses on all fronts.  There is always a energy loss on regen as you say so the more regen you use because of a heavier vehicle, harder regen from a higher speed, higher regen setting,  the more energy you loose.

If thats not the answer then please describe the question again.

PS i believe that 0.2kwh energy is stored in a car at 70mph.

Ken
« Last Edit: November 23, 2020, 12:20:02 PM by brackwell » Logged
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