Does pressing the brake pedal do any power regeneration?

Q

quietlyspinach

Active Member
Does anyone know if pressing the brake pedal, even lightly when slowing to a stop, produce any power regeneration?

The reason I'm asking is coming from a Prius perspective, lightly pressing the brakes does engage the power regeneration, and only when you drop below a certain speed does it then engage the physical brake pads to stop the vehicle.

When I drive the MINI down a long hill, I often find that I get a smoother ride if I switch to low-regeneration mode and lightly engage the brake pedal. It *feels* like the car is using the regenerative braking, which is sort of subjective, but I wasn't sure. In the Prius there is a dashboard view which shows you how much energy is getting recaptured. The instrument cluster takes away one of the two zones below the "Ready" point when you flip on low energy regeneration, implying it still does something at a lower level.
 
quietlyspinach said:
Does anyone know if pressing the brake pedal, even lightly when slowing to a stop, produce any power regeneration?

The reason I'm asking is coming from a Prius perspective, lightly pressing the brakes does engage the power regeneration, and only when you drop below a certain speed does it then engage the physical brake pads to stop the vehicle.

When I drive the MINI down a long hill, I often find that I get a smoother ride if I switch to low-regeneration mode and lightly engage the brake pedal. It *feels* like the car is using the regenerative braking, which is sort of subjective, but I wasn't sure. In the Prius there is a dashboard view which shows you how much energy is getting recaptured. The instrument cluster takes away one of the two zones below the "Ready" point when you flip on low energy regeneration, implying it still does something at a lower level.
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I believe the brakes are unrelated to the regen. When you let off the throttle, the car regenerates at either high or low regeneration, depending on your mode selected. Adding in brake disc friction has no effect, other than to scrub off energy that would have otherwise, eventually, been turned into regenerated Wattage.
 
The brakes are unrelated to regen but the OP question still stands…does the regen get involved at all when braking with the regular brakes or is it one or the other? As in how integrated is the regen braking system?


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So my gut feel is that slightly depressing the *brake pedal* does not immediately engage the physical brake calipers; it does appear to engage something similar to what I feel is the electric regeneration/slowing that I experience when putting my Prius into "B" mode. I can feel a distinct difference when the pads hit the discs a little later; with the windows down I can also hear a difference as well. But I haven't heard of this behavior documented anywhere officially.
 
From my experience driving the SE I think there are essentially two independent braking systems on the car:
  1. Traditional friction brakes, tied to brake pedal: engaged when brake pedal depressed and used by traction control
  2. Regenerative braking, tied to accelerator pedal: engaged when accelerator pedal released
This is speculation based on my hours driving, but I've never felt any relationship between regenerative braking and the friction brakes. If I don't stop in time with regenerative braking I'll use the friction brakes and it seems to "override" any regenerative braking going on.

They both clearly trigger the brake lights, but that could be based on inertia sensors or something.
 
quietlyspinach said:
So my gut feel is that slightly depressing the *brake pedal* does not immediately engage the physical brake calipers; it does appear to engage something similar to what I feel is the electric regeneration/slowing that I experience when putting my Prius into "B" mode. I can feel a distinct difference when the pads hit the discs a little later; with the windows down I can also hear a difference as well. But I haven't heard of this behavior documented anywhere officially.
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Hybrid cars have a much more complicated system. The one in our Clarity Plug-In Hybrid is incredibly complex. However, there's no reason to tie the SE's brake pedal into the regen circuits. What do you believe is happening when you slightly depress the SE's brake pedal? I believe the car has just 2 levels of regen, with no third level reserved just for people feathering the brake pedal. If you want to stop faster than with regen alone, the tried-and-true vacuum-powered brakes are there to help you out.
 
The simplistic braking may also be a result of the SE being a retrofit into the existing ICE platform. Instead of a major redesign, MINI added electrics including regenerative braking to the existing production line so it doesn't surprise me the friction braking is essentially identical to the ICE models and separate from the regenerative braking.
 
A lot of the EV/Hybrid blended brakes feel like junk imo. I couldn't believe how bad the Jag's braking was in the blended mode. Couldn't stop smoothly once in a 30 minute test drive.
 
In my eGolf the brake pedal uses regen as much as it can to slow the car down before blending in friction brakes. This is the case no matter if the car is in one of the 4 levels of regen or just “D” in which lifting off the accelerator pedal allows the car to coast. In my normal day to day driving the friction brakes usually only come into play from 5mph to a stop. The downside to this is a very soft brake pedal and squeaking. I find the MINI’s brake feel so much better.


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quietlyspinach said:
Does anyone know if pressing the brake pedal, even lightly when slowing to a stop, produce any power regeneration?

The reason I'm asking is coming from a Prius perspective, lightly pressing the brakes does engage the power regeneration, and only when you drop below a certain speed does it then engage the physical brake pads to stop the vehicle.

When I drive the MINI down a long hill, I often find that I get a smoother ride if I switch to low-regeneration mode and lightly engage the brake pedal. It *feels* like the car is using the regenerative braking, which is sort of subjective, but I wasn't sure. In the Prius there is a dashboard view which shows you how much energy is getting recaptured. The instrument cluster takes away one of the two zones below the "Ready" point when you flip on low energy regeneration, implying it still does something at a lower level.
Click to expand...


There is not much technical material out there for the Mine SE but as people have suggested on here it may have a regen function. The one pedal driving with full regen means you are either moving forward or slowing down, with the lower regen setting allowing more of a coasting effect slight depression on the brake pedal may engage more regen. I have seen EV's with a regen effect before the mechanical brakes engage but unsure if the Mini uses this function. I use the one pedal function all the time only braking with the brake pedal when absolutely necessary.
 
I think F14Scott had it correct. The moment you let off the accelerator, the regen kick in. The brakes just add frictions braking to the already active regen. I believe that is why the brake feel is so good in the MINI - it isn't trying to be tricky and blend regen and friction. You can also tell that regen is active by just looking at the power meter.
 
Knowing how the Germans obsess over efficiency and energy savings if there is an advantage to the electronics slowing the vehicle over friction brakes the Mini will have that feature. The 3 phase motor can be slowed down electrically without using generating power to charge the battery, its just a case of how efficient that would be in everyday use. The brakes are so good it feels like a combination of both friction and electrical braking, that's just my opinion and not based on any actual Mini technical specification. It would be nice to ask a Mini or BMW tech about the technical aspects but I doubt they would give much away as battery power management are closely guarded secret within the EV industry, how to get more with less.
 
moff1959 said:
Knowing how the Germans obsess over efficiency and energy savings if there is an advantage to the electronics slowing the vehicle over friction brakes the Mini will have that feature. The 3 phase motor can be slowed down electrically without using generating power to charge the battery, its just a case of how efficient that would be in everyday use. The brakes are so good it feels like a combination of both friction and electrical braking, that's just my opinion and not based on any actual Mini technical specification. It would be nice to ask a Mini or BMW tech about the technical aspects but I doubt they would give much away as battery power management are closely guarded secret within the EV industry, how to get more with less.
Click to expand...
Perhaps an OBDII wizard will be able to determine if there's a third, more powerful, level of regen that can be activated only with the brake pedal.
 
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