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Discussion Starter · #1 ·
Coasting to a stop a longer distance before hitting the brake or braking a bit earlier and getting the car to use as much regenerative charging as possible?
 

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Coasting to a stop a longer distance before hitting the brake or braking a bit earlier and getting the car to use as much regenerative charging as possible?
Using power to maintain speed for a longer period before using regen braking over a shorter distance will always be less efficient than coasting for the total distance. Regen only returns a fraction of the power that is required to maintain a set speed so there is a net power reduction, while coasting uses zero power so power remaining stays the same.
 

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Marina Blue HEV Ltd IONIQ from 25 Jul '17
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Using power to maintain speed for a longer period before using regen braking over a shorter distance will always be less efficient than coasting for the total distance. Regen only returns a fraction of the power that is required to maintain a set speed so there is a net power reduction, while coasting uses zero power so power remaining stays the same.
Well, as long as nobody is behind you, who may get p'd at you. But if you've got the room...
 

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Timing your coasting so you can stop without brakes is very efficient. I can manage to do that sometimes on uphill stops (relatively fast deceleration doesn't annoy cars behind). Of course, slower constant top speed and regen is likely more efficient in many scenarios than faster cruise speeds and coasting. Probably close enough to the same ETA on trips of less than 25 miles so as not to matter.
 

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Discussion Starter · #5 · (Edited)
How about opening your window versus air conditioning in the Ioniq?

On a regular ICE car, the experts have been arguing back and forth about which is more efficient and the latest I've heard is opening the window is more efficient. The air condition puts enough drag on the engine to make it consume more fuel.

However, the Ioniq is extremely aerodynamic and traction battery can power the air conditioning compressor with little waste, would it be logical to say that opening the windows would create enough wind resistance to be less efficient?
 

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If temperatures are only moderately high, the better option is to turn the car's fan on, for example on two bars, or maybe three, but without AC. That doesn't really take energy, and you save the perfect economy of the car. You can do that by turning the knob right under, and after that, you press the AC button off.

For the results, look at your energy overview screen. AC 0 Watt, other electricity about 200 or 300 Watt, as usually.
 

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Discussion Starter · #7 ·
What about that driver's only HVAC button? Is that a gimmick or does it actually equates to real savings?
 

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You can try, but for heating, it gives less comfort, is my own experience.
 

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Marina Blue HEV Ltd IONIQ from 25 Jul '17
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How about opening your window versus air conditioning in the Ioniq?

On a regular ICE car, the experts have been arguing back and forth about which is more efficient and the latest I've heard is opening the window is more efficient. The air condition puts enough drag on the engine to make it consume more fuel.

However, the Ioniq is extremely aerodynamic and traction battery can power the air conditioning compressor with little waste, would it be logical to say that opening the windows would create enough wind resistance to be less efficient?
On the show Mythbusters, they had to do this experiment twice. The first experiment was conducted at 50 MPH (~80 km/h) and found windows more efficient than A/C, but after viewers wrote in they conducted the experiment again at a faster speed and concluded that at speeds over 55 MPH (~90 km/h), A/C is more efficient than windows.
 

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I don't use AC enough to tell the difference on our pretty efficient AC. However, in my last car, a PT Cruiser, AC brought efficiency down 4/5 mpg from an average of 28 mpg or greater than 10 percent.


Bjørn Nyland did a high speed and low speed test windows vs AC, personal belief that AC is more efficient, found the opposite.
 

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Marina Blue HEV Ltd IONIQ from 25 Jul '17
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Interesting experiment. However I feel his experiment colluded the Mythbusters experiment, which he did indeed reference, but he only referenced their initial experiment, but not their followup experiment.

Further, Bjørn's experiment also had windows opened a fraction, while Mythbusters I believe had the windows opened all the way, which I think would certainly affect the drag.

Another question I have about Bjørn's test, is how long was each run? How many km? how many minutes did he drive for? In the initial Mythbusters test, I believe they each started with 5 gallons of fuel and drove until they each ran out, driving around a track. Their second test I think they both drove for about an hour, starting out with equal amounts of gas in identical brand new trucks in traffic.

I see in the video Bjørn was talking about waiting for the car to cool and/or heat up, but it still didn't sound like he was starting with identical conditions within the car, I dunno, it didn't sound clear that he was actually starting each test with identical interior conditions, and if he's only doing short trips, then that will definitely affect the results. Long trips, not so much probably, but we don't know how long his trips were. Further we also know that exterior temperatures were different for each trip as he was obviously doing them all in the same day and he even said the outside temperature was rising.

Funny, his only voiced complaint about the Mythbusters experiment was they they used two vehicles. But he failed to point out the the vehicles were both brand new identical models and trims with almost equal low mileage and both had their tanks emptied and filled with the exact same amount of fuel, making the only weight difference the difference between the two drivers, Jamie and Adam. To me the Mythbusters experiment seemed much more scientific. The only problem with their initial experiment was that it was a low-speed test only and thus they had to follow up a year later with a high-speed test.

There's just too many differences in each of Bjørn's tests, for me to give it much clout.

As for me, for trips of 20 minutes or more on a hot day, I probably will use the A/C, or if I have a passenger and we want to be able to converse without shouting. But if it's just me and it's a short trip, or the temp is under 25°C, I'm much more likely to put the driver's window all the way down and open the sunroof. This for me delivers a nice comfortable airflow. I have not done any fuel efficiency experiments, because, quite frankly I can't be bothered to, and also I'd rather be comfortable than worry about whether I'm eking out the best mpg.
 

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It appears distance was 21 km. Sufficient enough for EV methodology where you can measure power used much more directly using Wh/km. That cuts out a lot of potential errors using ICE cars and fuel measurements - which if he said explicitly would be another "complaint" (but his videos are already overly long). With about 15 minutes per run, the environmental conditions will not change as much as on another day, or long runs.

EVs are inherently better than ICE vehicles with tests involving power and efficiency. I'm not sure why the quibble about how far down the windows were, they were set for best comfort. That is a valid test parameter, and yes, it might lend itself to a slightly different result than Mythbusters experiment. But for the relative result that he was seeking, perfectly valid methodology.
 

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Discussion Starter · #14 ·
Braking at the last minute, driving with all the windows open and air conditioner on full, under inflate tires and carrying around extra stuff in the back..GOT IT. ?

I think someone should conduct an experiment when a hybrid car would get the absolute worst mileage as possible so we can establish a threshold and work backward.
 
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