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The video is not a bad primer, but for an EV driver it leaves out explaining the efficiency of regen and the amount of energy that one can recover by using regen. The speaker in the video explains that this is in another video (which I didn't bother to look for).

A couple of good explanations that I've found on regen efficiency are here:

http://www.teslamotors.com/blog/magic-tesla-roadster-regenerative-braking

http://proev.com/LLPgs/LLei0005.htm

So the net result is that due to inefficiencies (losses) in the conversion of electric to kinetic and then kinetic to electric (and inefficiencies in battery charging) that if you start at the top of a mountain with an empty battery and then roll down it with regenerative braking that when you reach the bottom and turn around to drive back up the mountain that you'll only get maybe 25% up it. (Driving away from the bottom then along a level road would be a considerably different thing.)

This is why the Volt, when operating on "extended range mode" (where the petrol generator is providing electric current for the drive motor and also keeping the battery SOC to 30%) pushes power directly into the motor in addition to charging the battery rather than simply charging the battery and letting the motor run exclusively from the battery. (Because there is considerable loss in battery charging.)

This is also why the Prius is more-efficient in petrol usage than the Volt (when in extended range mode). The Prius takes kinetic energy from the combustion engine and applies it directly to the wheels whereas the Volt converts the kinetic energy of the petrol combustion and converts it to electric to then drive the wheels with the electric motor. The Volt only does this in extreme conditions. (The Volt has its valid reasons for doing it this way due to its design, of course.)

[When reading the links I provide above be aware that the Tesla blog comes from a theoretical perspective while the ProEV.com discussion comes from a more pragmatic one. Hence, the Tesla blogger writes that the conversion efficiencies are "quite high", quantifies "pretty good" as 80%, and does not include aerodynamic loss and road friction loss in the 64% efficiency statement. Whereas the ProEV.com discussion chooses to factor-in all losses and works from a real-world test instead of a theoretical one.]

One interesting takeaway from this reading for me is that regen is less-efficient at very light application. Apparently it's more-efficient when applied aggressively (but without engaging the disc brakes). This actually seems to agree with what I've experienced in use. (I've noticed that driving in "L" on the Volt - where regen is much more aggressive - recovers more charge than when I drive in "D" and use light braking over a longer distance to accomplish the same that "L" would in a short distance.)
 

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This is also why the Prius is more-efficient in petrol usage than the Volt (when in extended range mode). The Prius takes kinetic energy from the combustion engine and applies it directly to the wheels whereas the Volt converts the kinetic energy of the petrol combustion and converts it to electric to then drive the wheels with the electric motor. The Volt only does this in extreme conditions. (The Volt has its valid reasons for doing it this way due to its design, of course.)
True, provided by "extreme conditions" you mean any time the Volt in CS mode maintains a steady speed above 30mph for more than about 30 seconds.
The Volt cannot provide full power to the wheels when the ICE is driving them directly, so it won't do that when accelerating, but otherwise parallel hybrid is the norm.
 

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True, provided by "extreme conditions" you mean any time the Volt in CS mode maintains a steady speed above 30mph for more than about 30 seconds.
No, I mean the conditions that bring about the "direct mechanical connection" described in this article:

http://www.motortrend.com/features/editorial/1010_unbolting_the_chevy_volt_to_see_how_it_ticks/

... when it states: "Above 70 mph, when the generator couples to the ring gear, the engine gets a more efficient direct mechanical connection to the wheels."

I've driven the Volt faster than 70 mph, but I've never been able to notice any operational difference. However, I have heard comments from Volt or Ampera users where this "direct mechanical connection" is obviously engaged in "extreme" conditions such as accelerating hard from a stop up a steep incline.

You are correct, however, that this mechanical connection cannot drive the car alone... battery assist is still necessary.
 

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No, I mean the conditions that bring about the "direct mechanical connection" described in this article:

http://www.motortrend.com/features/editorial/1010_unbolting_the_chevy_volt_to_see_how_it_ticks/

... when it states: "Above 70 mph, when the generator couples to the ring gear, the engine gets a more efficient direct mechanical connection to the wheels."

I've driven the Volt faster than 70 mph, but I've never been able to notice any operational difference. However, I have heard comments from Volt or Ampera users where this "direct mechanical connection" is obviously engaged in "extreme" conditions such as accelerating hard from a stop up a steep incline.

You are correct, however, that this mechanical connection cannot drive the car alone... battery assist is still necessary.
Yes, a lot of the early articles (the one you linked is from 2010) got this wrong. As I understand it Chevrolet simply said that at higher speeds the engine could drive the wheels directly and some journalists interpreted that as meaning above 70mph. In fact when some of the guys over on gm-volt.com looked at how the Volt actually performs they found the magic cutover speed was much lower (I've seen various speeds quoted from 35 to 45mph).

It is quite easy to tell when the engine has been connected directly to the wheels. (1) the engine must be running (ok, actually sometimes it can be hard to tell this for sure), and (2) when you put your foot down there is a delay before the car accelerates.

As I wrote above, the design of the Volt means the main motor cannot output full power when running in split mode with either the secondary motor or the petrol engine. So any attempt to accelerate in split mode starts by switching to the single motor mode and gives you a slight delay before the car kicks forward. When you put your foot down, if there is no delay power was coming only from the main motor; conversely if there is a delay then either the secondary motor or the ICE was also providing direct drive to the wheels.
 

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In fact when some of the guys over on gm-volt.com looked at how the Volt actually performs they found the magic cutover speed was much lower (I've seen various speeds quoted from 35 to 45mph).
I assume that this is only true in charge-sustaining mode because I never see any petrol usage otherwise. Thus...

(1) the engine must be running
 

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I assume that this is only true in charge-sustaining mode because I never see any petrol usage otherwise. Thus...
The switch from single motor to split mode happens whether or not the petrol engine is running but not necessarily under exactly the same conditions as the purpose of split mode is rather different. In charge depletion mode the secondary motor MGA is used to reduce the speed of the main motor MGB keeping it in a more efficient range, whereas in charge sustaining mode the split is to allow the petrol engine to provide drive to the wheels without the generator/motor conversion losses.
 
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