Verkehr said:I don't disagree. Let me restate that I was referring only to "going down hills where coasting will result in higher average speed" e.g. any steep hill since one obviously can't alter the topography with their driving style.NeilBlanchard said:Verkehr said:Regen is better than coasting for recovering potential energy (going down hills) where coasting will result in higher average speed and more aero losses, though.
It all depends on what you need to do: if you want to carry speed (and you can) then coasting is best. Regen should only be used when you need to slow down.
Coasting has the lowest loss possible - and uses the kinetic energy to move the car forward. Regen can never regain all the energy (by definition) so it is better than friction brakes - but it cannot substitute for coasting.
Aero losses will always happen, so that is a red herring.
The other aspect of coasting is that you accelerate less - so you use significantly less energy, and then use the kinetic energy you have "invested" in the moving car in the best way possible. In B mode, you accelerate and then regen, so you use more energy, then lose more.
I thought of another real world coasting-buster scenario: no traffic, travelling 55 mph, light turns red 1/8 mile up the road (or whatever particular distance a 55 mph e-golf would coast for). It's a long light... coasting all the way up without touching the brake is less efficient than regen braking hard and then travelling at a slow rate (~15 mph) before coasting to a stop; every moment spent at higher speed is more kJ being used to heat the air. Regen losses are quickly overcome with less energy lost in the air. Just a way of lowering average speed with little effect on travel time.
ulrichw said:I drive in B all the time, and after a short adjustment period, it seems like a much better way to drive than the old-fashioned way. I have no problems coasting. The brake/accelerator model seems a little bit like having two steering wheels - one to turn left and one to turn right.
Also, the way you control the speed doesn't perceptibly change whether you're going level, uphill or downhill, whereas with the brake/gas model you have to make more of an adjustment. If you're going uphill, lifting will decelerate you quite significantly, so you don't switch to the brake until you really need to slow down, while going down a steep hill, you accelerate even when completely off the gas, so you need to switch to the brake even if you just want to hold your speed. With the two-way pedal, your "zero point" changes, but when you're driving, the adjustment is completely intuitive - you don't even notice that the "hold my speed" point is at a different point in the travel of the pedal.
bizzle said:I tried B like you guys are talking about and it seemed like a pain in the butt to keep it perfectly on 0. Seemed like a lot of hunting. I only tried it for a mile or so, though, and then was over the experiment.
Much easier to simply coast in D and flip the shifter to B like a manual downshift.
Incidentally, I find that as long as I keep the gauge around 2-4 in the green then I'm definitely not using friction pads. It might even be most of the green portion of the gauge but I can't say for certain.
JoulesThief said:I prefer to drive the same way as Bizzle.
ulrichw said:I think some people in this thread are hung up in ICE-land.
In an ICE car, you coast by lifting your foot all the way off the gas pedal.
You might want to look up 'Torque Converter' for ICE cars. That does allow coasting (well...there is a slight drag)NeilBlanchard said:ulrichw said:I think some people in this thread are hung up in ICE-land.
In an ICE car, you coast by lifting your foot all the way off the gas pedal.
No, lifting your right foot in an ICE slows the car by using the engine - which shuts off the fuel - but is not coasting, because the car is being slowed by the engine. So, most other EV's mimic this ICE behavior.
The e-Golf in D is like no other EV - and VW did this for a reason. It is more efficient.
By driving in D1, D2, D3, or in B, you are mimicking an ICE, with downshifting.
A coasting automatic transmission is meant to approximate a manual transmission in neutral.forbin404 said:You might want to look up 'Torque Converter' for ICE cars. That does allow coasting (well...there is a slight drag)NeilBlanchard said:ulrichw said:I think some people in this thread are hung up in ICE-land.
In an ICE car, you coast by lifting your foot all the way off the gas pedal.
No, lifting your right foot in an ICE slows the car by using the engine - which shuts off the fuel - but is not coasting, because the car is being slowed by the engine. So, most other EV's mimic this ICE behavior.
The e-Golf in D is like no other EV - and VW did this for a reason. It is more efficient.
By driving in D1, D2, D3, or in B, you are mimicking an ICE, with downshifting.
dlaituri said:In my orientation session at the dealership, I think they captured it well - D modes are like various degrees of downshifting, B is like a secondary brake pedal.
I was also told when you take your foot off the pedal in B mode, the brake light comes on (haven't confirmed this)... and I've noticed stepping on the brake also increases the re-gen kw, suggesting braking with the pedal is a calculated combination of re-gen + pads & rotors.
Third observation - when the car is fully charged, D and B modes don't do much to slow the car - there's no place for the charge to go
My game: time hitting B mode at just the right point so the car comes to a stop at the right spot!
Just did that yesterday to a tail gater.dlaituri said:Keep in mind that when you're in B mode, every time you take your foot off the accelerator, the brake lights come on. For someone following you, it can look like you're a crazy double-footer (left foot on the brake, right foot on the gas)...
SJCyclist said:Why would you call one of the most unique features about the car "gimmicky"? Having the ability to adjust is fantastic and was a big selling point of the car for me.
Jaysher said:I have had a question that I don't see discussed here:
Does it take more power/electricity to move the car forward in B mode than in D mode? Since B mode gives you that feeling of resistance/braking it seems like it would, but I'm not really sure how it works.
I often drive to the city, which is 60 miles on flat interstate with no traffic. In D mode is there really less resistance, so is it more efficient in energy use since there's no braking or downhill coasting?
That's what I do but I haven't tested the hypothesis. I pop it into 1,2 or B as soon as I approach the off ramp or any traffic.
BTW I use 1, 2 and B all the time in local driving - it's like a game to use them as much as possible and the brake as little as possible.
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