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Anyone know what the max regeneration rate on a Gen 1 is? I see up to -40 on the kw meter but is all of that being absorbed by the battery or at some point is just dissipated?
Maximum regen rate?
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Max regen on the Gen 1 is 60kW. It is spec'd as such and I've seen it several times slowing down while coming off an interstate exit.
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I've seen the same.
Hmmmm, how exactly are y'all achieving the 55+ kW rates?
For example, when I get off the Interstate at the exit I use most frequently, one crests a hill and in my ICE vehicles, I just cancel cruise and still have to brake strongly at the bottom about a mile from the crest.
In my Volt, I'll cancel the cruise and if nobody is behind me, I'll drop it into Low at 70 MPH and still have to brake halfway down the off ramp. In this scenario, I will see 12 - 15 kW peaks before touching the brakes and increasing to 14 - 17 kW while braking. I think I saw it hit 18 but I have never seen a number of 20 kW or greater.
I'm basing this on the "Engine" graphs in the main instrument cluster / LCD with the bars at go up in yellow and down in green. I have MyGreenVolt but have not compared those values.
Added: From a topo map, I estimate the elevation drop about 55 feet from the crest to the traffic signal at the bottom of the exit ramp... not exactly a mountain but still a hill nevertheless.
For example, when I get off the Interstate at the exit I use most frequently, one crests a hill and in my ICE vehicles, I just cancel cruise and still have to brake strongly at the bottom about a mile from the crest.
In my Volt, I'll cancel the cruise and if nobody is behind me, I'll drop it into Low at 70 MPH and still have to brake halfway down the off ramp. In this scenario, I will see 12 - 15 kW peaks before touching the brakes and increasing to 14 - 17 kW while braking. I think I saw it hit 18 but I have never seen a number of 20 kW or greater.
I'm basing this on the "Engine" graphs in the main instrument cluster / LCD with the bars at go up in yellow and down in green. I have MyGreenVolt but have not compared those values.
Added: From a topo map, I estimate the elevation drop about 55 feet from the crest to the traffic signal at the bottom of the exit ramp... not exactly a mountain but still a hill nevertheless.
My understanding is MGA is the smaller motor, which is clutched to the engine in Range Extended mode to generate electricity "on the fly" as fuel for MGB, the primary traction motor.
Braking regeneration is created by MGB using the car’s momentum when this motor is not providing propulsion torque to the wheels (e.g., when coasting in D or L, slowing down, or being pulled downhill by gravity).
When comparing recharging rate potential, note that Mountain Mode is capable of using MGA to recharge a fully depleted 2012 Volt battery to the 45% MM-maintained level (~4 kWh) in 15 minutes, using 0.36 gallons of gas (see the Self Charging Volt youtube video).
I would think max regen rates are not normally sustained for 15 minutes or more.
Correct me if I'm wrong but my theory is when you brake lightly only one motor is regening. Then when you depress the brake a bit further the clutches work their magic and engage the second motor so it then regens as well.
I say that because when I slow down from highway speeds gradually braking more I'll reach a point where I hear a clunk or something (clutches doing their thing) then the regen amount jumps way up to nearly 60 or so.
I say that because when I slow down from highway speeds gradually braking more I'll reach a point where I hear a clunk or something (clutches doing their thing) then the regen amount jumps way up to nearly 60 or so.
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I see 55kW most times pulling off from high speed, and it may flicker a few kW above or below that. I presumed it was a half of the max power out, i.e. a half of 111kW (which again I see flicker a few kW over on rare occasions, right temperature and right battery SOC).
The DIC number is the total high voltage power of the system - if it's positive, power is being pulled from the battery (or engine)
If it's negative, that amount of power is being fed into the battery.
When braking or L-coasting to a stop, the rate of regen is proportionate to speed/rate of deceleration. If you're not going fast enough, you might not see that max number.
If you are driving in single motor mode, you will see maximum 55kW regen from the single large motor (half the max output)
If you were in dual motor mode, you might see up to 60kW regen as both motors work together. This isn't as common as the system usually declutches fairly quickly. Typically 55kW is max.
If it's negative, that amount of power is being fed into the battery.
When braking or L-coasting to a stop, the rate of regen is proportionate to speed/rate of deceleration. If you're not going fast enough, you might not see that max number.
If you are driving in single motor mode, you will see maximum 55kW regen from the single large motor (half the max output)
If you were in dual motor mode, you might see up to 60kW regen as both motors work together. This isn't as common as the system usually declutches fairly quickly. Typically 55kW is max.
Would you consider going into Low at 70 mph / 110 km/h be a situation where one would expect to see maximum regen?
What if I shift to Low and apply the brakes ?
(Assume comfortable temperatures and a battery that is isn't at a full state of charge.)
Shifting to L at that speed may get you there, but might be a bit below.
L+moderate to firm brake pressure certainly would.
But as you slow down, the regen rate will drop proportionately. So you'll only see 55/60kW max at the very start of the deceleration.
L+moderate to firm brake pressure certainly would.
But as you slow down, the regen rate will drop proportionately. So you'll only see 55/60kW max at the very start of the deceleration.
Between this and other messages on this BBS, I am now convinced that my car has an issue, but I have no clue as to what it is. Therefore I have started a new thread so as to not hijack this one and filled the first post with as much information and I could think of.
Thanks for your reply!
Thanks for this comment. It slipped my mind that when in two-motor mode, both motors are coupled to the drivetrain, and the car’s momentum could therefore use both to create braking regeneration. I would imagine the engineering would be remarkably complex. Surely it’s more efficient to use only a single powerful motor/generator to create regeneration, but that would require unclutching MGA from the powertrain in ev mode and from the engine and powertrain in power split mode. That process would introduce its own inefficiencies. And since regen often exists only for brief periods of time, subsequent demands for propulsion torque would require clutching the motor back into the drivetrain if the car’s speed and torque demands remained within the two-motor configuration parameters... whew!
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