No, Your EV Doesn't Regen "All The Power" Going Downhill
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- čas přidán 15. 01. 2024
- For some reason I hear this from a small number of folks out there whenever I talk about Ev efficiency in mountainous areas. "Mountains don't matter because you regen all the power going down." Here's the reality: it will always be less efficient to drive on hilly terrain because it will always take you more energy to go up the hill than you can recoup going down. To prove it I snagged a Polestar 2 and went on a drive.
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I never give grief over passing on the right because really it's the people in the left lane that aren't doing their job of getting back over after passing.
Which results in dangerous roads and more accidents... no matter how obtuse we are about it....
Have you ever visited Florida 🤣
I never passed on the right due to safety. Then I moved to Missouri. I got over that safety concern fairly quickly. My sanity was more important.
Various reasons for people to be in the left lane and going slower than the right lane. Maybe you have a left turn ahead and you're respecting the speed limit law. Or there's a road hazard. Or even other traffic. It's always been utter nonsense to expect this rigid adherence to the concept.
@@r5LgxTbQ Right, which is why passing on the right is totally fine. Not the ideal scenario, but there are always reasons where it makes sense.
Polestar gang. Side note: I absolutely love the regen braking on the Polestar 2 - perfect transition from regen to friction brakes at low speeds, and even when the battery is full or cold, it'll apply the same amount of friction brakes in one-pedal mode as when there is more room for regen; so deceleration remains consistent.
It's great to have options when it comes to regenerative braking but one of the features people look for in a brake pedal is that it feels the same all the time. Polestar has it right. -Travis
7:41 that Nissan Rogue has no chill
I have had one-way trips from Rocky Mtn Nat Park to Fort Collins, where I’ve ended with a higher SoC than I started with. A rare exception but pretty fun.
I love that while I need two DCFC stops to get to the mountains from SF in my e-Golf, I only need one DCFC stop to get home thanks to regen.
There's no doubt that regenerative braking helps extend an EV's range. -Travis
Kudos to Polestar for big improvements in efficiency with the 2024 model
Absolutely! -Travis
Thanks for the video
Awesome demo, have you tested one pedal vs coasting efficiency? I feel it's a similar topic in that again regen doesn't provide 100% back and when you let off the throttle it's slowing down the car and losing energy, but coasting is using all the energy that was provided for momentum, particularly for highway driving.
TLDR; coasting would come out on top. -Travis
Dunno about Polestar, but I've been getting back around 90% in Tesla S on a set of Eagle Touring. I've crossed the country many times, and all I need to know is the distance and starting/ending elevation to plan my charging. Ups and downs in between are not that significant factors.
The efficiency in EVs is just a matter of physics. If the regen is not capturing most of the energy back, the energy must be leaking in the form of heat or sound. If there is no such leakage, the energy must be going back to the battery.
Curves take substantially more energy than straight line, especially at higher speed. I notice this all the time going to the mountains in the Sierra. Your drive on Hwy 17 might have been substantially less efficient because curves there compared to I-280.
May I suggest you redo the test in a Tesla over, say, Altamont Pass on I-580? Hwy-17 with all those curves just isn't a good test ground.
Yes, I agree. The arguments presented in this video were not pursuasive. The mass of the car logically shouldn't be a factor. Ideally, rolling and wind resistance should be the only cause of energy loss, and these would be the same whether you're driving on a level road, or climbing mountains.
If an EV really is less efficient going up and down mountains than when driving level, then something isn't working as it should be. I do find it hard to imagine why curves would make such a large difference though.
@@eugene9852 The car has to push against G-force and that takes energy. And the heavier the car, the more work it takes because G-force is greater. You can actually see the power meter going up when you go around a long curve without slowing down. The car also needs to slow down/speed up when going in and out of the curves, and the variable speed is less efficient than constant one.
Whether those are enough to explain the difference that Alex saw, I don't know. But there is no point in that exercise, since you can't make any inference from an "experiment" that failed to control/randomize material variables or take them into account.
What would really be interesting to see is how much energy would be saved in a big ICE vs EV semi-truck comparison. ICE Semi-trucks are pretty heavy, not as heavy as their EV counterparts, but definitely not light. They don't have any way to recoup energy going down a hill, whereas an EV one can recoup nearly all of it if the battery is at the right charge level.
I mean, obviously the hills won't give back as much as they take, or else you could drive up & down the same hill forever and never run out of battery.
Not quite. There is always air resistance, and rolling resistance. These shouldn't be any different though when climbing hills vs driving on a level road.
There's nothing "obvious" about this result. Ideally, in an EV with regen braking, it should make no difference whether you're driving up and down hills. Clearly this has diverged from the ideal, and I'd be really interested in learning why.
Btw the little power meter on the dashboard will be white if using regen, or a sliver of hatched orange at the left end when the friction brakes are engaged.
Yep, but the slivers can be so small that upping the one pedal is the easy thing to do,.
@@EVBuyersGuide Agreed, better to keep an eye on the road lol. Even in the one-pedal-drive Standard mode, the car doesn't always fully fill up the regen part of the meter; I wish there was a Max mode.
i went to a SC in my tesla model 3 SR 2023 year and filled it to 100%
it was a 40 mile each way, and when i returned i stopped at the SC location i charged at for an exact distance.
the trip from SC to mountain (8000ft ) was all uphill in some form (a few slight uphill but near flat ground) and all freeway other than leaving the SC and freeway was under a mile away.
started with 270 miles of range, ended up with 112 miles of range at the top...to be fair, i was doing 70 on the freeway, and was having a lot of fun feeling the EV effortlessly going up the steeper mountain road and was doing 80-85 at many times, even hitting the gas to pass people doing 55. outside temp was in the high 90s and AC was on the entire time, set to 65F fan speed at about 4-5. my windows are heavily tinted so i dont need AC on coldest setting or on high. on mountain, temp outside was 70ish but left AC on. I did not use CC or AP at all for this trip. i had 2 heavy adult passengers in the car as well
the entire trip down, and to the SC was all some form of downhill grade on the exact roads i took up. Upon arrival at the SC i started at, I was at 148 miles of range remaining, doing about 60 down the mountain and 65-70 on the freeway back to SC (traffic was heavier by this time)
basically i used 122 miles of range for an 80 mile trip. considering i was hitting the pedal hard going up hill, and was basically driving it like i stole it so to say i would prob do better driving it normally, and my 40ish miles of loss would prob be more like 20.
to compare, my previous vehicle a 2022 tuscon hybrid, with a turbo 4, i would use a 1/4 tank just going up there, but my hybrid battery was always at max full coming back down and my distance to empty (gas range) would just keep going up and i would end up back home with barely over the 1/4 thank moved lower than that. (also its an SUV compared to a sedan i get that but concept no different)
on a more local comparison....for me to get to work from home its all a slight uphill grade, my hybrid above the MPG would say about 26 (rated 38 EPA), but on the way home, same road, i would get 60-70 mpg. my model 3 will show 300-350whpm to work (about 10miles or range used for a 7 mile trip), but 125-165whpm on the way home (usually a 2-3 mile range loss for a 7 mile trip, and had it as low as 100whpm once if i hit all the lights right.
The regen system on any EV or hybrid isn't 100% efficient. There are energy losses along the way in the regen system: rotational power to electrical AC current, AC current to DC current conversion, DC current to battery chemical energy.
Correct. -Travis
I own a Ford Focus Electric. I only gain regen when I can COAST above about 12mph. So a hill has to be steep enough to maintain at least that. A long, very gradual downhill slope won't earn me any regen if I have to use the accelerator pedal at all, though it certainly will improve ESTIMATED range. And the hills definitely take away a LOT more than they give back.
The hills aren't directly taking anything that they're not returning. Physics alone doesn't offer an explanation for this result. If there are additional losses, it must be additional heat from the batteries and cables.
It may not be completely true, but it's damn good! My Model 3 is fantastic going on mountain trips from home to the hill and back. You're not using energy on the way down so you're driving 1/2 the distance essentially, and not wearing out brakes as a bonus.
Yes, please see my response. I believe that this is more of a test of the Polestar's capabilities than those of EVs in general.
the math does not support your assumption
@@alwaysawn9110 this video does not contain the correct math, this is for the wrong vehicle. The regen tech varies widely, he needs to test this on several different vehicles.
@@Radium3D I was referring to your math, not his. It doesn’t matter if he was testing a volvo and not your tesla. Many others have tested this in a a similar way. The result is always the same. Which was his point. All vehicles are less efficient going up a mountain than any gain they get by going back down the other side.
Interesting results. I would have anticipated slightly better from the hillclimb relative to the flat driving but no denying the results. I just figured that the relative efficiency of an EV partially related to the percentage of time/distance it spent in regen and that is why EPA city drive cycles yield better efficiency numbers than highway most of the time (aside from average speed which of course affects aerodynamics and drag).
Its a polestar, one of the most inefficient vehicles on the market. Try the same with a Ioniq or a ID.4.
@@wolfgangpreier9160what does that have to do with the point of my comment? I was speaking about relative efficiencies.
@@ALMX5DP Yes, exactly my point. relative efficiencies are always worse if the driving efficiency is bad.
They use the same electronics, cables, software, batteries, connectors.
If they do not want to achieve highest efficiency when driving the car, they put even less effort into highest efficiency while braking it.
@@wolfgangpreier9160 I’m not sure what you mean. This specific vehicle got pretty decent efficiency when driving on level ground. That was my reference point when I commented about how inefficient the hillclimb and decent combination was.
@@nc3826 I’m not assuming anything, just curious why the descent leg did not yield a little better result that is all.
Alright Alex, I have one for you drive an empty ev pickup up a mountain, harvest some fire wood and load that sucker down. What is regen with a full load back down?
It's a fun hypothetical but unless there are some pretty extraordinary circumstances it wouldn't gain all the energy back that was used in going up the mountain. -Travis
applicable to ppl who didnt pass high school physics....
Literally my first thought... conservation of energy but forgetting where the inefficiencies show up...sure... no wind or IR loss or drivetrain loss.
And what explanation does your high school physics provide for this result?
Blended brakes are the best! I won’t buy an ev without them
Stupid slow CA drivers in left lanes always bug me. In New England highway, you either got jammed to stop or flying 95 mph in the left lane!
Haha! This is where a PHEV will shine. Hybrid up the hill. Use all electricity in the battery. Maybe even use a gallon of gasoline. Get to casino. Plug in. Eat dinner. Gamble. Go back home 4 hours later. Show 284 mpg for the trip. Recharge at home. $2 for electric, and one gallon of gas to get up the hill.
Long downhill sections benefit a PHEV over a standard hybrid because there's a lot more room to capture regenerative braking energy. -Travis
i have driving fun to not be bored and non attentive partially for saftey reasons, i do it by trying to get max miles per gallon and not wearing out the tires by using them to slow down a lot . its like old school endurance racing at more relaxed pace(if you arnt in a rush to get to places quickly), you minimize need for pitstops for fuel tires lubricant etc. for example, you preserve momentum around turns instead and speeding up again, but dont loose traction. . you brake and steer minimally but steadily, build up momentum downhills and at optimal rpm and power level according to bfsc chart for the engine (electric motors also have this ) . you maintain speed that is less than roughly 50 mile per hour (if car is more areodynamic, you can tolerate higher speed, but cutting through the wind becomes expnentially less effceint as you increase speed linearly). although climate crisis stuff isnt proven and the politics is obviosuly led by people who dont care about it, chemcial toxicity affecting food supply and sustainability og the buisness model of car design, are good reasons to do this if the money savings means nothing to you.
That's a very long description of "hypermiling". -Travis
Alex, Are you absolutely certain we can handle the truth? 🤔
if only it were the truth....
So, I have done extensive driving of my Tesla Model 3 LRDM from Victor, Idaho (6,214 ft) to Jackson, Wyoming over Teton pass (8,431 ft.) and back, I've have found that the car achieves almost exactly the same miles/kwh as it does on level ground. In the case of my car, this would be 225 wh/mile, or 4.44 miles per kwh. I've done this route at least 50 times and have gotten very consistent results. Similarly, when I drive the car from Long Barn, CA (5,043 ft.) to Sonora Pass (9,624 ft.) and back, the results are the same. I've done the Sonora Pass run many times as well.
So, why are my results different from yours? I'm guessing that there are 2 possible causes. The first is that it is entirely possible that the reiteration of the Tesla is simply more effective than that of the Polestar. The second is that in my 2 test cases these are substantial and fairly steep elevation gains, and perhaps that makes a difference.
Either way, my experience has been that the car achieves virtually identical "flat-ground" efficiency when being driven up and down substantial grades. As a side note, I've owned my Model 3 for 4.5 years and have about 60k miles on the clock. I've driven these routes in the heat of summer and in the case of Teton Pass, when it's frightfully cold outside.
Bottom line is that I think your conclusion should be qualified, because what you experienced is substantially different from my experience driving this car over these passes many, many times. While I'm sure your data is correct for your car and your route, it's quite different from what I've experienced. Suggest you try the same experiment in a Tesla and see what results you get. While I think you may have proven something here, I think it might be something different from what this piece suggests.
I would agree with this, can you retest with a model 3?
Same here with Model S. I've done about 5 cross country trips and all I had to know has been the distance and starting/ending elevation to plan my charging. 50% difference that Alex saw is just out of whack; Polestar regen must be leaking energy all over the road like ICE.
We did this in our SR+ Model 3 as well as a non-plaid Model S. We got very similar results. The consumption on Model 3 was lower, but the delta between hill and flat road driving was nearly identical.
Are there really people thinking regen makes efficiency equal to the same distance on a flat surface?
Yep. Just check out the comment section...
Can you explain exactly why though?
My fuel car doesn't regen anything at all... So the EV does win that battle.
Very true and we're not saying it doesn't. It's more about trying to clear up confusion than say "regenerative braking doesn't do anything". -Travis
Don't tell Porsche... they claim regen doubles the losses and is less efficient than no regen.
I can't say I've seen them put it THAT way. -Travis
I don't get the love for one pedal driving. You can use the brake pedal to regenerate and feel in control of your vehicle. I love my brake pedal on my Ford plug-in hybrid.
I like that you drive it just like a regular car while getting the benefits of regeneration.
Kinda feel the same way. If the vehicle is tuned right I like having the accelerator just control acceleration and the brake pedal to control deceleration (using regen and then friction brakes if needed).
I like single pedal driving it's just simpler to press to go a lift to slow I don't need to move foot back and forth unless someone cuts you off or something.
Having owned a Prius and now a Tesla Model 3, the benefits of one pedal driving are pretty clear. Nobody has figured out how to blend regenerative and friction braking such that brake feel is the same as it would be in a good friction braking system. Tesla made the choice to keep them separate, and the result is that Teslas have excellent brake feel....because it's just friction braking....not that you use it much.
@@dangrassThe blended braking in the Mach-e is really good.
Its not true because it violates the laws of thermodynamics (to begin with). 😂😂😂😂 Its like the guys that think an alternator would be a great idea on an EV😂😂😂😂
How does it violate the laws of thermodynamics? Clearly additional energy is lost, but where exactly?
It’s called perpetual motion and the holy grail of energy if you go equal from going up 😂 it’s Against the Laws of Physics
Such a shame. -Travis
Obviously there will always be air resistance and rolling resistance, but these are the same as when driving on level ground. Can you offer an actual reason as to why there are additional losses when climbing hills?
@@eugene9852 isn’t the video named going downhill? That’s not what this video is about as for going uphill on a std charge on my testing you’ll always use more on inclines as you’re using power to climb which applies to all craft including rockets 😁
Nice but I'd like to see another comparison in real mountains. Like 12,000 feet or higher. Big regen in my experience.
Yes, while I'm sure that Alex was honest in reporting the results, I suspect that this test was not representative of what most EV owners experience.
Of course, but it would also use more energy to climb the mountain. -Travis
No magic, no 100% efficacy!
100% correct. -Travis
I would be curious how close to a “perpetual motion machine” an EV could hypothetically be. Obviously not in real world driving, but I’d love to see a video where you drive 0-10mph, and then regen back to 0, and do that for about a mile and calculate efficiency. How close to 1000 mile range could it get? Again, irrelevant in the real world where you have to maintain speed and don’t spend equal amounts of time accelerating and decelerating, but would make for an interesting video.
That's not how that works at all... You'd get more range just maintaining a set 10mph than what you're describing. Regen doesn't add miles to your range. It just gives you back ~90% of what would have been lost to heat with friction brakes.
As an EV owner, I can tell you that regen braking does put energy back into the battery. So by driving at 10mph, then stopping, you recover energy during the distance you’re stopping, rather than using energy to maintain 10mph. Anyway - just think it would make for an interesting video
As an EV owner, I can tell you that regen braking does put energy back into the battery. So by driving at 10mph, then stopping, you recover energy during the distance you’re stopping, rather than using energy to maintain 10mph. Anyway - just think it would make for an interesting video
@@JamesM-hb2cj it only puts back part of the energy it took to accelerate in the first place. A percentage of the energy is being lost in the process due to inefficiencies in the process. No mechanical process is 100% efficient. There is always waste energy. And accelerating uses more energy than maintaining a constant speed. So all together, the process of accelerating/decelerating over and over is MUCH less efficient than just maintaining a constant speed. Regen is better than no regen, but it's not a magical free energy process.
If see the long record EV they are all done on a track going 20-30mph because just having the car on uses energy. So you need to go fast enough that driving uses more energy than the electronics, but not too fast to be fighting the air.
Also the whole point of the video was regen doesn't " give" you energy, it only recovers a portion of the energy used to get going.
I feel like there were better things to test out than something that should be common sense.
common sense but showing real numbers validates it.
What he said...... and varying the parameters will change the relative results anyway.......
It's actually not, when I've talked to people about EV. They have asked about that vehicle with the generator attached to the wheels 🤦♂️
With the level of confusion amongst consumers it seemed worthwhile to put some time towards this. -Travis
Travis, The problem is technically it proved nothing... Since how does testing one EV on one downhill road course prove or disprove that 'Your EV Doesn't Regen "All The Power" Going Downhill? The answer is it doesn't. Deterministic 'common sense', is often superior to an anecdotal test.
But my real issue is I'm hoping for a higher level of discord on this channel.
Lastly, why doesn't Alex ever try to prove the advantages of BEVs? For example BEVs reduced NVH. Love to see that on AoA. Alex has always had issues with BEVs and his choice of topics and his narrative reflect that fact.
Travis, I have high hopes for the channel, when you obtain some editorial discretion over it, good luck.
Great, so on the next post, you are going to show that tires wear out on BEVs, too? To prove that they are not maintenance free?
I hope you can find much more productive uses for this channel? There are hundreds of pragmatic EV topics that you could cover. But in the meantime thank you for confirming that entropy actually does exist. SMH
And where is Trevor, I thought he was supposed to be in charge of this channel? Since he had some intriguing ideas about the direction of the channel.
That's not a bad idea, talking about tire wear in EV's. It's a lot more torque than people are used to and their tires are going to feel that. We've got a lot of videos coming down the line, don't worry! -Travis
@@EVBuyersGuide I was being sardonic, but indirectly alluded to what you stated about tires... So I do look forward to the post on it and when you take over the channel... Plus I am sure the subject matter will be more objectively chosen (Alex has always had an issue with BEVs, such as his perception that they require an excessive amount of batteries)..... Good luck
@@nc3826 I'm not sure what you mean. (Alex here) since I've owned several EVs. What I **have* said in the past is that if global gas consumption reduction was our goal, then the batteries we **can* make currently could be put to better use. However, that's simply a "thought experiment" because there is no global car design czar that could order that. This means we have to make personal choices based on our own needs and desires. I do believe that efficiency should be more of a factor than it is which would reduce the quantity of scarce materials used in each new BEV. But I have never suggested that BEVs use an excess number of batteries, they simply use the number required to get the vehicle to the range that customers want. There is little focus on **real** improvements in charging speed that could allow for more shoppers to be comfortable with smaller batteries. Yes we have the promise of solid state batteries soon, but nobody is working hard on a nation wide charging network capable of more than 350kW for consumers. There are talks of megawatt charging for commercial vehicles but we are a decade plus away from charging anything mainstream at a rate over 350 kW for any length of time. Even at 350kW if it could be sustained from 0-100% SOC would still mean a long charge time for a RAM REV or Escalade iQ or Silverado EV. Hence the focus on efficiency, if you use less energy then you don't have to stuff as much in the car to go the same distance.
@@EVBuyersGuide Alex, my last comment was actually directed at Travis. But since you replied I was mostly pointing out the fact that Travis brings his own perspective to the channel. (BTW you owned EVs, since that's part of your business, it does not prove your fully objective about all of their aspects.)
And how does anecdotally testing an individual Polestar 2 on a particular downhill road course, prove that, 'Your EV Doesn't Regen "All The Power" Going Downhill'? Taking one specific case, doesn't prove a generality. While, simply copying and pasting a proof, for why 'perpetual motions machines can't exist', with regen added to the title, would have been far more conclusive proof.
(And therefore specific efficiency claims, and the rest of the rabbit holes you went down. And therefore it was not worth addressing them in a CZcams comment section. Since it would taken so much time and effort to analyze each one and come up with relevant counterpoints, that have dubious value. FWIW battery swapping will be the best 'long-term' counterpoint.)
Lastly what were your thoughts on the Kia PBV? And all the related subtopics, such as it's going to be built in microfactories. I know it's not initially planned for the US, but there are tentative plans to sell it worldwide. It could even get here before they fix all the bugs in the EV Blazer;)
@@nc3826 Based on business case alone we shouldn't have bought EVs for long term testing as they don't represent the bulk of sales the USA. We bought them because I like them, always have. And, no they were not all business cases. We had a Kia Soul EV for three years and a Nexo H2 fuel cell for three years as well. Although we did some content with them, we didn't do much because nobody cared about them but me. EVs have been my preferred mode since I can charge them myself as I live 100% off grid.
The Polestar was simply used as an example, a data point. Physics and thermodynamics tells us all we need to know about regenerative braking. Regen braking can never recover as much energy as it took to climb a hill or accelerate to a particular speed. Regardless of the EV, at a given speed it will always be more efficient to travel on level ground because it takes more energy to move mass uphill against gravity than you will recover going downhill. If motors were 100% efficient, cooling would not be required, but even that is not the only factor.
It would if they used supercapacitors for regen
Nope. Thermodynamics.
Exactly.
Nope, simple high school physics
@@dylanluhowy what about using some kind of wind up spring, like in toy cars?
@@charname-player never had that lesson in physics class. Never seen it tested. There’s no data.
although there is no evidence for humans causing climate change beyond natural climate change, there is evidence and some very apparently suspicious artificial chemical stuff, which is now known to be definitely harmful, such as dirtier forms of combustion, tire wear dust(see xenoestrogens, microplastics, etc) , wiper fluid etc. best way to use non fully recyalable limited battery supply (which is almost always never recycled ) is to have small combustion charging battery and electric assisted turbo in lightweight areo car. weight makes it less crash safe for everyone involved in crash, worsens road wear damage and tire wear , exponentially, and makes preserving momentum around turns less possible to minimize degradation of battery from regenerative braking , then powering up again after regenerating the energy less efficiently than how it would be in preserving momentum around a turn. . ev are heavy because high weight per energy , you arnt using all that energy at a moment of driving but you are carrying all thr weight. instant torque makes it worse. @EnriqueThiele having the sedan jump up to have its structurally strong parts lower in the car, hit the strong parts of other car before crash, would also have higher safety with all the supremacy in balanced values of sedans. a lotus style lightweight agile momentum preservaton sporty driving can be integrated into encouraging effceint low emission driivng to make driving fun and safer, too recent honda insight is closest we got to this ideal , but they intentionally didnt do their best becayse they were afraid people wouldnt buy their car as much if they made a aesthetically weird shape like prius , they wanted to get people whos buy prius if only it didnt look weird . they knew almost every who says they care about emissions actually do not care(mostly because low trust in "the science" and its funding), and they are already far less than 5 percent of all customers , so they comprimised. noone praises honda or prius, they praise tesla for making a gossip attracting toy r
no evidence for humans causing climate change? Are you kidding?