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I have been reading about regen and I couldn't find a answer to this. Do you have to be totally off the throttle to go into regen?

For example, if you are going down hill and let off the throttle your might to slow down. So you add in a small amount of throttle to maintain speed. Does the controller just reduce the amount of regen load on the drivetrain or totally shut off regen and just take enough charge out of the battery to maintain speed? Does touching the throttle take it out of regen?
 

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regen is adjusted to maintain the throttle position you are at.
 

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In your DIC there is a screen that shows power usage both applied as well as regen. There are effectively 3 total segments, the upper left is power being applied to the motor/generator and is indicated in yellow, the upper right indicates power from the engine when operating also indicated in yellow, and the lower left shows regen indicated in green. It also has a numerical indicator in KW how much power is being used or regenerated. Depending on how steep the descent grade is, you may need to apply some acceleration which will reduce or eliminate any regen that may be occurring. If possible, using cruise control will definitely maintain your speed and maximize your regen ability. If necessary you can also shift into L if D doesn't provide enough regen to keep your speed from climbing above the set speed.
 

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Discussion Starter #5 (Edited)
Ok, thanks. That is what I suspected. I figured they could vary the load to take advantage of even slight regen.

I'm shopping and reading right now. I joined this forum just before the Volt was released (and promptly forgot my user name and password) but I needed to enjoy my HHR SS for a while longer. Time for a change!
 

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Top center of Driver Information Center-a + kw reading shows power applied to drivetrain/a - kw reading shows (regen)power to batt.
2017 LT-Heather gray metallic + Comfort Pkg
 

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As others have said, feathering the accelerator will produce varying amounts of regen. For those two foot drivers out there, though, there's a caveat. If you hold the accelerator near neutral or in the power range and press the brake pedal, it doesn't override the accelerator - instead the friction brake pads are applied immediately, even at light braking levels that would normally be all regen.
 

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You can see when the Volt is charging the battery on the DIC. I'm not sure what model years that's available in (Hopefully all), but my 2014 has it.

https://youtu.be/DThiQQJHNS4?t=1m9s
Just as a note the power flow display is available on 2013+ Volts. 2011 and 2012 Volts do not have the detailed power flow diagrams.
 

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Just as a note the power flow display is available on 2013+ Volts. 2011 and 2012 Volts do not have the detailed power flow diagrams.
Good to know.

Does it still have the Prius-like power flow diagram on the infotainment screen?
 

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I've found that I drive with Cruise control much more in the Volt because it maintains the speed and automatically adjusts regen to maintain that speed.
 

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...I'm shopping and reading right now. ... I needed to enjoy my HHR SS for a while longer. Time for a change!
Just go test drive one !!!

And while you're at it drive a Bolt.
I realize a 238 mile range BEV won't suit everyone's needs, but test drives are free !!

Just beware: Do you know how to tell when a car salesman is lying?
And when the test drives are done: Act like you just got a txt and say you have to go. DO NOT go back inside....
 

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No but it does help if you are going downhill or can otherwise maintain your momentum without too much input. Unfortunately I can't try the CC method that often because of drivers who constantly sprint-drift.
 

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Seems to me that the Gen 1's primary motor/generator MGB cannot act as both a motor and a generator at the same time.

Current from the battery or from the output of MGA acting as a generator can flow through MGB’s coils to turn its shaft and provide propulsion torque to the wheels via the drivetrain. Or, when propulsion torque is not being applied to accelerate or to maintain speed, the car’s momentum can be used to turn MGB’s shaft mechanically (the rotating wheels are linked to MGB’s shaft via the drivetrain), and MGB can now generate power (i.e., regeneration) back to the battery.

No doubt the Volt is engineered to switch between motor and generator operation as needed. Feathering the accelerator will produce varying amounts of regen only when MGB is operating as a generator... thus if you have one foot on the accelerator using motor output (i.e., not just gravity) to accelerate or to maintain speed, stepping on the brake pedal with the other foot has no regen to influence, and so engages the friction brakes.
 

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Seems to me that the Gen 1's primary motor/generator MGB cannot act as both a motor and a generator at the same time....
No EV, no motor/generator can 'act' like that. That would be called Perpetual Motion.

The 2 M/G in the Volt are controlled by the inverter/controller (or whatever the proper name.)
3 AC wires to each motor - 2 Big Ass DC wires going to the battery pack.
It's either current going in or current going out of the battery pack. The right foot decides.
 

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Seems to me that the Gen 1's primary motor/generator MGB cannot act as both a motor and a generator at the same time.
You can think about it as that the "motor" mode has the field lead the rotor. "Generator" drags the field along behind the rotor. So long as everything can stay clutched the same way, though, it can switch back and forth REALLY FAST though.
 

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Seemed to me the OP’s original question, "Do you have to be totally off the throttle for regen?" indicated some uncertainty on how regen was created. I suppose many first-time Gen 1 Volt owners, like me, didn’t know there were two electric motors, not just one, under the hood with the gas engine, and that when the car was coasting or slowing down, MGB became a generator that could recharge the battery... and that when the gas engine started up, it was clutched to MGA to generate electricity as fuel for MGB, not to the drivetrain to propel the car.

"Maintaining throttle" to keep moving at a given speed requires using propulsion torque. I suppose it would be possible to engineer the Volt to be propelled at times by MGA only, thus allowing MGB the freedom to act as a generator, but the amount of regen captured would be less than the additional energy needed to maintain propulsion torque with MGA while regenerating with MGB.
 

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The DIC is a good estimate of regen status vs pedal position (drive it and try yourself).
Full-off pedal in D is light regen, full-off pedal in L is medium regen (~0.7m/s/s for volt)
If you look at the DIC, it generally reads 0.5kW as idle. So if you're driving along and hold the pedal such that the display reads 0.5kW you are (within margin of error of the display) +/- not regen and not accel either = true coast.
Press the brake pedal and regen will increase to max (if pressing hard), with the brake pads taking care of anything regen can't handle.

Full-off the pedal in D and you'll see it switch to the regen side of the display with a light regen rate - not a true coast.
L works the same way, but the default full-off pedal position is stronger regen than D.

However, using the DIC is only a ballpark estimate as the DIC is not measuring the power of the motor.
It's measuring the total high voltage system power. Most of the time, this is vast majority drawn or provided by the motor.
However, if it's winter and you have a 7kW heater blasting, you could be in regen per the operation of the drive and decelerating, but the display could still show a positive number. This is also true for AC and battery heat.
Something to keep in mind.

If you want to know the actual status of each motor (input vs output) you can grab the values with OBD and see if it's positive or negative power output. It would also be more granular than the 1kW increments of the DIC.
 

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Discussion Starter #19
Just go test drive one !!!

And while you're at it drive a Bolt.
I realize a 238 mile range BEV won't suit everyone's needs, but test drives are free !!

Just beware: Do you know how to tell when a car salesman is lying?
And when the test drives are done: Act like you just got a txt and say you have to go. DO NOT go back inside....
I might test drive one for fun but I have to do an occasional 800 mile run so the Volt makes sense over the Bolt if I don't care to take the Acura.
 

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and that when the gas engine started up, it was clutched to MGA to generate electricity as fuel for MGB, not to the drivetrain to propel the car.
... at low speed in Gen 1. "Sometimes not" in all other cases. Shake this whole "ICE never physically turns the wheels" concept. "ICE doesn't HAVE TO physically turn the wheels" is much more accurate, because it often does.
 
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