Mx5racer
Posts: 176
Joined: Mon Oct 18, 2010 8:59 pm
Location: Yorba Linda, ca

regen vs mechanical brakes

Fri May 27, 2011 6:39 pm

Is there any way to tell the max point of regen vs. mechanical braking
Do the mechanical brakes not start being applied until after all the brake dots are full?
I wish there was a light that showed the point that you were pushing too hard.
Silver SL
Yorba Linda, CA
5.9 Solar

palmermd
Posts: 2566
Joined: Fri Apr 23, 2010 3:19 pm
Delivery Date: 31 Mar 2011
Leaf Number: 1100011011
Location: Hermosa Beach, CA

Re: regen vs mechanical brakes

Fri May 27, 2011 6:45 pm

Feel how the car brakes when it is charged to 100%. That is almost all mechanical brakes. You'll notice there is a very light touch to not apply the mechanical brakes. When you are using regen (pack down to 80% or less), just barely push down on the pedal and the regen will go to maximum if you are going fast enough to regenerate. If you give any extra it will be applying the mechanical brakes as well.
Michael

Leaf from 31 March 2011 - Traded 18 April 2018 for Tesla Model 3 Unicorn
Driving electric since 1996


Leaf Bar Loss

User avatar
aqn
Gold Member
Posts: 819
Joined: Fri Oct 01, 2010 12:59 pm
Delivery Date: 30 Apr 2011
Leaf Number: 1333
Location: Austin, TX

Re: regen vs mechanical brakes

Fri May 27, 2011 8:37 pm

Mx5racer wrote:Is there any way to tell the max point of regen vs. mechanical braking
Is that a question

:D

Missing question mark notwithstanding, see Owner's Manual, page 2-7: "Instruments and controls"/"Meters and gauges"/"Power meter".
You get max regen when all four dots on the left light up.
When dots on the left have single-line circle around them instead of double-circle, it means that regen is being limited to prevent overcharging the battery. For example, when the battery is fully charged, all four dots on the left have single-circle border.

Mx5racer wrote:Do the mechanical brakes not start being applied until after all the brake dots are full?
The brake control module controls the amount of hydraulic brake assist by operating a pump in the master cylinder, coordinating between the traction motor's regeneration and signal from the brake pedal travel sensor (LEAF Service Manual, page BR-12). The brake control module does a gradual transition between regenerative braking force and hydraulically assisted braking force.

That said, I can always feel the cut-over point when the regenerative braking cuts out completely and braking becomes 100% hydraulic, when slowing down from speed to a near crawl. As I slow to a walking/jogging speed, I can feel a sudden twitch in the brake pedal and the pedal sinks a tiny bit.

Mx5racer wrote:I wish there was a light that showed the point that you were pushing too hard.
If all four dots on the left light up like a Christmas tree, there's probably regenerative energy being lost. (The "Energy Usage" screen of the "Energy Info" display in the center panel shows power used or regen'ed by the motor: navigation system owner's manual, page IT-3. Regen is at its max when the display shows -30kWh.) It's a bit of a game for me to gauge my braking distance/force/time to get max regen up until the moment I come to a stop.
Anna Nguyen

User avatar
turbo2ltr
Posts: 1376
Joined: Fri Jul 30, 2010 11:13 pm
Delivery Date: 04 Feb 2011
Leaf Number: 185
Location: Phoenix, AZ

Re: regen vs mechanical brakes

Fri May 27, 2011 8:54 pm

While you are braking, put the car in neutral. This will "turn off" regen and you can get a feel for how much mechanical brakes are applied.
Silver SL-e
Ford F450 Crew Cab Hybrid Conversion

KeiJidosha
Gold Member
Posts: 915
Joined: Sat May 01, 2010 11:57 am
Delivery Date: 26 Jun 2011
Location: Simi Valley, CA

Re: regen vs mechanical brakes

Fri May 27, 2011 9:06 pm

Mx5racer wrote:Is there any way to tell the max point of regen vs. mechanical braking
Do the mechanical brakes not start being applied until after all the brake dots are full?
I wish there was a light that showed the point that you were pushing too hard.

The more you drive, the more you’ll want right pedal regen. Intuitive, accurate, responsive, efficient. Nothing to distract you from your driving task. Problem solved!

User avatar
lemketron
Posts: 242
Joined: Mon Aug 02, 2010 10:46 pm
Delivery Date: 10 May 2011
Leaf Number: 1554
Location: Sunnyvale, CA

Re: regen vs mechanical brakes

Sat Jun 04, 2011 7:09 pm

KeiJidosha wrote:The more you drive, the more you’ll want right pedal regen. Intuitive, accurate, responsive, efficient. Nothing to distract you from your driving task. Problem solved!

Yes, I think of that as "stick shift" mode, which would make driving the car feel like you had a manual transmission stuck in first gear. I've driven the AC Propulsion eBox with adjustable regen set to "max" and that's exactly how it felt. It doesn't take long before you are driving with just the right pedal and not really using the brake much at all.

So what we really want is an auto vs manual "transmission" (feel) setting in the car. But if they add that, they should probably add per-keyfob settings, so my wife can leave her preference set to "auto". Sure would be nice if the different fobs also adjusted the seats and mirrors for each person, too...
Reserved: 4/20/10, Ordered: 10/27/10, Delivered 5/10/11
Drivin' on sunshine! 5.4 KW Solar PV, PG&E E6 TOU, Blink EVSE (EV Project)
20,000+ miles of zero-emission solar-powered driving at $.01/mile!

townsat
Posts: 15
Joined: Tue Dec 14, 2010 3:21 pm

Re: regen vs mechanical brakes

Sat Jun 04, 2011 9:32 pm

Adjustable regenerative braking. That is what every electric car should have.

User avatar
gbarry42
Posts: 888
Joined: Mon Jan 10, 2011 5:48 pm
Delivery Date: 06 May 2011
Location: Moonlight Beach

Re: regen vs mechanical brakes

Sat Jun 04, 2011 9:39 pm

Less regen in "D". More in "ECO". While coasting, of course.
And there goes the first capacity bar! At 24,000 mi on 9/9/2013.
Second bar at 30,500 mi on 2/7/2015.

User avatar
lemketron
Posts: 242
Joined: Mon Aug 02, 2010 10:46 pm
Delivery Date: 10 May 2011
Leaf Number: 1554
Location: Sunnyvale, CA

Re: regen vs mechanical brakes

Sat Jun 04, 2011 10:34 pm

townsat wrote:Adjustable regenerative braking. That is what every electric car should have.

Well, thinking about it some more, I'm not entirely sure I agree. Before I got my LEAF, I was sure that I would have preferred it to have a "max regen" mode if not adjustable. I was also convinced that I would hate ECO mode. But since I've had my car (for just a few weeks now) I've actually grown to think that they did a pretty decent job selecting and tuning the two modes that we do have (D and ECO). I usually use ECO because I want the more aggressive regen, but I also like the more direct responsiveness in D.

Perhaps most importantly, I suspect that most people who are used to driving a car with an automatic transmission will find that the Leaf is very similar to what they're used to, and will therefore help confirm that this is "just like a normal car" rather than something strange.
Reserved: 4/20/10, Ordered: 10/27/10, Delivered 5/10/11
Drivin' on sunshine! 5.4 KW Solar PV, PG&E E6 TOU, Blink EVSE (EV Project)
20,000+ miles of zero-emission solar-powered driving at $.01/mile!

Caracalover
Posts: 560
Joined: Sat Jun 04, 2011 10:47 pm
Delivery Date: 12 Mar 2011
Leaf Number: 0567
Location: Tujunga
Contact: Website

Re: regen vs mechanical brakes

Sat Jun 04, 2011 11:57 pm

I have had my Leaf for a couple of months now (#567), and have found drive mode is better for many everyday driving situations. I throw it into eco whenever I see a reason to slow down, since it is a gentler way to engage the regen than using the brake pedal. I also don't want to be the slow poke leaving the stop light - no reason to, I am already cleaner than any other vehicle near me, and the cost is negliglble since I can regain a portion of the energy by slowing after the quick start. I have gotten pretty good at feeling when the max regen point is hit, and the display mentioned above does help - I wish it was the default screen - the map is too distracting for me, and the radio too boring. I touch the blue menu button and then the energy info button on start up, it is a clearer guide than the in dash dots.
26,000 miles on Silver Leaf
wildcatzoo.org drive there on Sunday across a big mountain, sorry no public charging at this time.
Looking for grants to put in solar port so perhaps in the future...

Return to “Engineering”