Coasting versus Regen?

[Hengus]

Bear with me please - as I am getting on in years!! In simple terms, what is the difference between coasting and regen? I can see when I am accelerating and charging but I can't tell when I am coasting. To add to the confusion ( well at least mine), I have seen comments about it being better to be in Comfort in warm weather at 70mph than in ECO Pro or ECO PRO+. In my first 100 or so miles, I have tended to drive around on narrow country roads in ECO Pro +. The app says 100% efficiency - however, from time-to-time, I get the foot on the accelerator icon on the top right of the screen.

 

[FrancisJeffries]

Bear with me please - as I am getting on in years!

Me too.
Coasting is when there is no charge going into or out of the battery. That's when the white marker is pretty much central.
Regen(eration) is when kinetic energy from the car's motion is being put back into the battery as charge. The conversion of kinetic energy slows you down. Conversely, the conversion of electrical energy to kinetic energy speeds you up.
I don't bother with EcoPro or EcoPro+ modes. They are too boring: I love the liveliness of the car in comfort mode. And the gain in mileage or "greenness" on the EcoPro modes is pretty pointless IMHO. :lol:
That app is pretty useless, too - I have no idea what it purports to show, so I ignore that too.
Just enjoy the car!

 

[Hengus]

Thanks. It's taken me a week to work out what the term GOM means so you can tell that I am new to all this. My grandson reckons that the men in white coats will be calling for me soon ( deep down, I think that he is quietly impressed but dare not admit it).

 

[Jeffj]

If you pay attention to efficiency (e.g. mi/kWh in the US or kWh/100 km elsewhere, I think), then EcoPro and EcoPro+ make a difference.

EcoPro limits the power to the wheels. Its still there, you just have to press harder on the accelerator. If you are in EcoPro and accelerate hard, you'll get the little picture of the foot on the accelerator on the control display, indicating you should light-foot it a bit. EcoPro also reduces the battery consumption for heating/cooling (meaning heating and cooling runs at a lower rate, drawing less power). This may or may not be desirable to you.

EcoPro+ limits the accelerator even more, and doesn't give you the option to override. It pretty much eliminates jack-rabbit starts and mashing the accelerator to pass. It also turns off climate control entirely, except for the defroster. As far as I know, the only way to get just the fan to blow (with no actual climate control) is to have the car in EcoPro+.

The net result of both EcoPro and EcoPro+ is to reduce power consumption, thus getting you greater range (e.g. higher efficiency). Whether you want this or not is up to you. EcoPro might get you 8-12% more range than Comfort, all things considered. EcoPro+ a few percentage points more.

As a general rule, heating takes more power than cooling, so ironically its more efficient to run with the AC on than with the heat on. Think of the number of degrees you are attempting to change with each. With heating, you might want to change cabin temperature by 20 to 60 degrees (Farenheit), but with cooling, its pretty rare to want to change the cabin temp by more than 10-15 degrees (Farenheit). If you want to cool the cabin, it will take less power to run the AC than to drive with the windows open (above 25 mph or so), as the aerodynamics are greatly affected by open windows.

Also, the "fan" control in the console behaves differently than you might expect. Its actually an intensity control, meaning that the higher you have it set, the harder the car tries to work to keep the cabin at the desired temperature. While this often involves running the fan at a higher speed, it also uses more energy in either heating or cooling. In other words, its not just a fan control.

 

[jadnashuanh]

Coasting is like free distance traveling...using energy to go or accelerate, or slowing down are not as efficient as letting inertia or gravity move you along. While regeneration helps when you do need to slow down, it is not 100% efficient at doing it, so coasting and never using the brakes should be your goal for maximum range and smoothest driving experience. A steady speed, rather than speeding up, and then slowing down is also going to maximize your range and make any potential passengers happier, too. If you use the cruise control on those boring roads, it is optimized for this and will make a difference in your range.

 

[Hengus]

All very useful stuff - thank you. I have a 100 mile trip coming up in a couple of weeks time on country roads so will test out cruise control.

 

[alohart]

EcoPro+ limits the accelerator even more, and doesn't give you the option to override.

Are you certain about this? I drive exclusively in Eco Pro+. Occasionally, I need to accelerate rapidly to merge onto a freeway from a short onramp. Pressing the accelerator to the floor in Eco Pro+ scares my wife due to the resulting neck-snapping acceleration. I can't imagine that maximum acceleration would be any greater than this in Eco Pro or Comfort modes. Reducing maximum acceleration could be a safety issue that I'm sure BMW and its customers would want to avoid.

If you want to cool the cabin, it will take less power to run the AC than to drive with the windows open (above 25 mph or so), as the aerodynamics are greatly affected by open windows.

Honda claims the same thing with our very aerodynamic (0.25 cd) 2000 Honda Insight. It has instantaneous and cumulative fuel efficiency gauges. Driving at a steady 100 kph with the windows down results in a higher instantaneous fuel efficiency than when I close the windows and turn on the A/C and its compressor. When the compressor cycles off, the instantaneous fuel efficiency might be slightly better than with the windows down, but the improvement is almost buried in the data noise. The instantaneous fuel efficiency drops considerably when the compressor cycles on because the cruise control must depress the accelerator a bit to maintain the same speed due to the considerable compressor drag on the small 1-liter engine.

With our i3, I have tested this assertion by driving the same route using ACC at a steady freeway speed (between 55 and 65 mph) both with windows down and with A/C on and windows up. With windows down, my average fuel efficiency (mi/kWh) is higher than with A/C set to 72º, fan at setting 2, outside temperature in the low 80's, and steady, normal trade winds. Only when I have driven with A/C on does iRemote rate my efficiency at less than 100%.

Based on my experience with our 2 very efficient cars, I don't believe that increased drag with the windows down below 60 mph uses more energy than driving with the A/C on. It makes sense that it would be more efficient to drive with the A/C on if the outside temperatures aren't too hot and the speed is high enough that increased drag would be significant, but I don't normally experience those conditions. Have any of you i3 owners tested this?

 

[MikeS]

I have stopped using eco pro or eco pro+ as I find they don’t affect the range I get as I tend to run with the heating off. If I drive normally comfort mode then I achieve the same range without the car trying to Nanny me!

 

[RJSATLBA]

I'm noticing the potential increase in range from using EP or EP+ is steadily reducing as the weather gets milder but using EP+ (or turning the heating off) makes a significant difference when you need to get a few extra miles to reach the next charger, even if you ignore the 56mph EP+ limitation and cruise at the same speed you normally use.

Personally, I prefer the softer throttle response in EP.

 

[WoodlandHills]

One practical difference between EP and Comfort is the throttle response when using ACC in traffic. The soft throttle response in EP causes large gaps to open up between me and the car in front before The ACC can catch up and close the gap. In Comfort the car keeps up with the guy in front very nicely and I dont have people always cutting in front of me causing a hard brake by the ACC. BTW in traffic I always set the ACC to follow as closely as possible to prevent others from constantly pulling into the gap in front of me, but I still end up getting cut off all the time when in Eco Pro as the car really lags behind the one in front.