2017 Chevy Bolt EV Cd 0.312

[NeilBlanchard]

Originally Posted by sendler

How does the e-Golf coast?
.
Keep in mind Chevy uses permanent magnet motors which have eddy losses (cogging) when "coasting". So you would need a neutral position in a transmission to really coast.

In D it free wheel coasts when you lift your right foot off the accelerator. It integrates regenerative braking on the brake pedal.

It also has 4 levels of regen available when you lift your right foot: D1 is the lightest, D2, D3 and B is (near) maximum regen. These are best used for long downhills and are just like downshifting in an ICE.

This is a close to perfect as I have ever driven. No other EV is this easy to ecodrive.

The Bolt EV as I understand it, has mild regen in D, and more regen in L. It has a paddle on the back left side of the steering wheel that increases regen up to the maximum. It has NO regen on the brake pedal.

The brake pedal should have integrated regen, because this works without having to learn a new method. And if D had no regen, then I would be happy. Designating the greater regen mode L is what I think of as a Klingon - evidence of old thinking that really doesn't communicate the real purpose. B is what the Prius has been using for a long time now, and the Leaf has been using for a couple of years.

[sendler]

No accel, no decel coast would be more accurate than the term freewheel which implies disconnecting the motor with a clutch. The motor is still being turned by the wheels and trans. The one pedal drive scheme also "free wheels" but does it at a partial position of the accel pedal instead of at off pedal. Advanced Volt drivers discovered this by selecting L, and promoted this when they realized improved efficiency. The friction brake pedal is never touched during the complete trip with the Bolt.

[redpoint5]

Originally Posted by sendler

The one pedal drive scheme also "free wheels" but does it at a partial position of the accel pedal instead of at off pedal.

Yeah, but that requires a large dead zone in the accelerator to be able to keep it in coast mode. I try to hit that point on my Prius plug in, but it's extremely difficult. I suppose wasting a few hundred watts as I coast isn't a big deal, but it would be more efficient if I could achieve 100% coast.

The thing is, they should have allowed the coasting mode to be selected since it doesn't add any cost to the vehicle. It's just a software mode that requires no additional hardware.

[sendler]

It must work well in practice since it is prefered by the active forum members with Volts who can choose.

[vskid3]

Originally Posted by redpoint5

The thing is, they should have allowed the coasting mode to be selected since it doesn't add any cost to the vehicle. It's just a software mode that requires no additional hardware.

We can't have people deciding what they like! We tell them what they like and they like it.


I greatly prefered the no-pedal coasting in my Escape Hybrid to the no-pedal regen in my Prius. I'm pretty good at holding the pedal in the sweet spot to coast in the Prius, but I shouldn't have to. You can bet that it'll be a factor I consider whenever we get another car.

[redpoint5]

Originally Posted by sendler

It must work well in practice since it is prefered by the active forum members with Volts who can choose.

Most people choose convenience over efficiency. Just look at how popular automatics are compared to manual transmissions. 1-pedal operation is more simple, but not as efficient, and possibly less safe. I wonder how many people have crashed because they aren't used to using the brake pedal when they need more stopping force than the regen creates?

[sendler]

Well this is turning into a nit pick. None of us has even driven the car. The Bolt will be a great car. The Spark is already doing better numbers than the Leaf and the Bolt will one up that again. And have a gigantic battery so that even getting stuck in a traffic jam on a cold day won't have to cause range anxiety.

[sendler]

Originally Posted by redpoint5

brake pedal

It still has a brake pedal. You just never have to use it unless you need it.

[Grant-53]

With all the permanent magnet DC motors I build, the controls have power applied to the armature windings or not. The regen mode means the spinning armature is sending current back to the battery. In dynamic braking mode the brushes or leads are connected. This is how we do no skid stops. A mechanical brake would be a separate system.
Designers have a choice between mimicking the current ICE pedal controls or using steering wheel mounted cruise control type system with paddles. Image using a game boy control with electric steering.

[NeilBlanchard]

Originally Posted by sendler

No accel, no decel coast would be more accurate than the term freewheel which implies disconnecting the motor with a clutch. The motor is still being turned by the wheels and trans. The one pedal drive scheme also "free wheels" but does it at a partial position of the accel pedal instead of at off pedal. Advanced Volt drivers discovered this by selecting L, and promoted this when they realized improved efficiency. The friction brake pedal is never touched during the complete trip with the Bolt.

Coasting in an EV doesn't require a clutch to be "real". There is almost no friction, and virtually no load when the reduction gear (aka transmission) and the rotor are spinning. A manual transmission has more internal friction, even with the clutch disengaging the engine.

I have driven the i3 (my brother owns one) and while it is easy enough to use (it has a easy to find "neutral zone" on the accelerator), it is not as good as the way the e-Golf does it.

The most important thing to realize about how the e-Golf works is: it defaults to coasting without the driver learning anything new. You learn how to ecodrive just by driving.

The Bolt EV would need to be driven in L and you would need to use the steering wheel paddle to get close to the i3 in terms of regen, and it remains to be seen if it has an easy to find "neutral zone" on the accelerator.