Spark EV Braking Issue

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markcmann

Well-known member
Joined
Jun 24, 2013
Messages
145
Location
Southern California
Have any of you Spark EV owners noticed an issue with braking to a complete stop (gradual not slamming on the brakes) and felt a pulse (skipping) or almost like the rotor is warped? I have a little over 400 miles on the car and have been very careful in breaking in the brakes by not slamming on the brakes and using the 'L' mode more often to take advantage of the regen but the last day or two I've noticed this and wondered if it normal or not? I might need to take it in for service to check into it?
 
i had that "alright, you should stop now" feeling, with all my brake pedal down, on my test drive. for some reason i'm expecting to feel it again sometime. i wasnt in L, i was in normal drive. it felt like some sort of a flywheel was still spinning and pushing the car. i want to have it happen again and investigate further.
 
markcmann said:
Have any of you Spark EV owners noticed an issue with braking to a complete stop (gradual not slamming on the brakes) and felt a pulse (skipping) or almost like the rotor is warped? I have a little over 400 miles on the car and have been very careful in breaking in the brakes by not slamming on the brakes and using the 'L' mode more often to take advantage of the regen but the last day or two I've noticed this and wondered if it normal or not? I might need to take it in for service to check into it?
Well apparently this is a normal operation of the electric motor engaging (or releasing) during the process of braking at low speeds or at least according to the Service Adviser at the Rydell Chevrolet dealership in Northridge, CA. I dropped the car off this morning because of this issue and due to the fact the car was pulling to the left when braking as well (hence my concern of a warped rotor, etc.) but although the tire pressure status showed a consistent reading of 33 to 34 psi on all tires, the front driver's side tire was nearly six pounds low. So for future reference, always consult a good tire pressure gauge measurement first if you experience this type of condition. Oops! :oops:
 
I may have experienced a similar issue yesterday. I was coming to a stop coming out of a parking lot. The road was clear so I did not come to a complete stop and felt a thump and heard a kind of bang noise. It did seem like the motor was disengaging and then re-engaging when I hit the accelerator pedal.

I haven't been able to reproduce the issue and everything appears to be normal.
 
wutangmo15 said:
I may have experienced a similar issue yesterday. I was coming to a stop coming out of a parking lot. The road was clear so I did not come to a complete stop and felt a thump and heard a kind of bang noise. It did seem like the motor was disengaging and then re-engaging when I hit the accelerator pedal.

I haven't been able to reproduce the issue and everything appears to be normal.
Sounds very similar to what I have been experiencing. It's not entirely clear to me if this has been happening since I took ownership of the car or if once I noticed it I'm hyper-sensitive to it now? But according to the dealership's service adviser, this is normal and they verified it by duplicating the issue with another Spark EV that was on the lot. I do notice it more when backing up (in reverse) and stopping to change the gear selector to 'D' (drive) and I do notice it more when coasting (or creeping) and then applying the brakes; not when pressing the brakes from normal speeds like if traffic stops or slows in front of you. So I'm a little glad someone else has the same experience as I didn't want to have a problem with my new car. :)
 
I hate to bring this up again but have any of you Spark EV owners noticed the odd computer modulated braking issue which feels like a pulsing, stuttering or skipping sensation at very low speeds when lightly applying brake pressure to the pedal right before coming to a complete stop? It's a bit unsettling and feels like something is wrong. I can duplicate the issue in reverse, drive and low gear and it's driving me crazy.

According to the Chevrolet Service Advisor, this is "normal" but it really seems like something is ether adjusted wrong or the computer modulation is calibrated incorrectly. It's my understanding the braking system on the Spark EV is not the same as a conventional automobile and is basically a "brake by wire" system as opposed to a traditional mechanical hydraulic system. Anyone???
 
The car apparently uses an electro-hydraulic system for the front brakes.

The below was taken from a Chevy media kit -> http://media.gm.com/content/media/us/en/chevrolet/vehicles/spark-ev/2014.html

The front brakes include an electro-hydraulic regenerative brake system that captures braking energy...

I've driven my girlfriends Spark EV a few days, after she noticed similar braking concerns to yours, and I only felt a pulsing/pumping sensation as the car powered-up. I've never noticed that feeling while coming to a complete stop. (Though I was using L quite a bit to modulate & control braking before stops) I do think it can be the nature of some regenerative brakes to be a bit grabby right before coming to a stop. We also asked Chevy, and they responded that it's normal for the car. Not that it's any consolation for someone who finds it to be an annoyance.

As an aside, I must say as a Leaf owner - the Spark EV is a supremely fun car to drive.
 
FYI I'm having brake problems...

http://www.mychevysparkev.com/forum/viewtopic.php?f=9&t=3722&p=6541#p6541
 
This is also happening to me and I find it extremely annoying. I took my EV in to get it checked for this and they were unable to reproduce with my car or with a new car from lot. Hence they concluded this was "normal." WTF? They cannot reproduce therefore it's normal!

My theory is this, if this ALWAYS happened, then yes, it could be normal. However, because it is non-deterministic, the only conclusion is that something is not properly calibrated. Maybe it only happens when decelerating at the threshold between switching between electrical and mechanical braking, in which case a hysteresis loop may solve the problem. I don't know, all I know is that I find it EXTREMELY annoying.
 
Yep, this is my main complaint about this car, I absolutely hate the braking system. All I can say is that I'm glad I'm leasing and hopefully my next EV (whatever it is) has better brakes...
 
I read these threads, and sure can't relate. My Spark EV's brakes have been great. I have never heard any odd sounds, except a hum approaching the stop at the end of the block when I leave home. I assumed that was the electrical braking assist bringing things up to pressure.

Only odd thing is when the parking brake is applied, the car can roll forward and back an inch. It is like the brake mechanism is floating a little before it comes to a hard stop in either direction.
 
I agree, I am surprised at the complaints about the braking system. I've had a complete loss of power boost while autocrossing, which scared the shit out of me, but since I was on a closed course and using the system in a pretty abusive course it wasn't so surprising and it was manageable (just ruined my timed run!). If you guys think the normal use of these brakes is an issue, you'd be IRATE if you experienced this abrupt loss of power boost! I've also experienced lack of regen with a completely fully charged battery, but this is to be expected since the battery can no longer accept a charge. I wish it was more consistent, but I understand why it is that way.

Personally, I think the Spark EV has one of the best "feeling" blended brake setups I've ever driven considering how much regen it has. It's no M5 when it comes to feeling, but if you compare it to other EV/PHEV vehicles with blended brakes it's quite good. It was certainly on par with the i3, in my opinion.

Bryce
 
This is normal. I experience this strange sensation with my Spark EV as well and I'll explain.

Keep in mind that the regenerative braking system is pretty unique and the braking can feel different at times. When you brake lightly, the front hydraulic brakes are not active, it is the motor that is regenerating causing the front wheels to brake. At the same time, the electronic brake modulator is activating the rear brakes hydraulically. This is allowing all 4 wheels to slow down. Half regen half hydraulic.

When you reach a certain speed, usually below 5mph, as in coming to a stop, the electric motor is not capable of effectively braking by regeneration. At this point, you will feel the braking system change how it brakes. The electronic brake modulator will transistion and deactivate regenerative braking from the motor and activate the front hydraulic brakes which is causing some people to feel the motor "disconnect". In fact, the motor never does disconnect, it's a direct drive. It is the transition from regenerative to hydraulic that is being felt. You might also notice the brake pedal is a little harder to press. You now have all 4 wheels braking hydraulically. The hydraulic system is charged by a high pressure pump that you will hear everytime you turn your Spark EV on. You'll hear a motor sound for about 10 seconds...This is the hydraulic system charging. When you turn your Spark EV off, you will hear the system make a clunk sound and hear a swoosh sound. This is the hydrualic system bleeding the high pressure charge. Also, press the brake pedal after you turn your Spark EV off and after you hear the clunk and swoosh. The brake pedal will be hard. Start the Spark EV up with your foot and you will feel it sink and soften as the hydraulic motor charges the system.

Now, another interesting characteristic I have noticed, is that if I am on the freeway and brake all of a sudden (I commute on the 405 everyday and there is a lot of slamming on the brakes in front of me) and I'm braking hard, there will be no regeneration at all. It's full hydraulic for all 4 corners. I know this is happening because if you look at the gauge cluster, the regen symbol is not spinning or is spinning, but only regenerating at 3-4KW instead of like 60kw if you are braking hard with regen. It also feels harder to brake which may feel like you lost brake boost, but you haven't. I think this is so the hydraulic system has full control of the ABS system.

Speaking of, if you activate the ABS, you will see a message pop up that says "Low Traction", indicating ABS activation in hard braking.

Just my 2 cents. There is nothing wrong with the braking system and it's just how it works based on the EV technology. It does take some getting used to, but it is what it is. Hope my explanation helps! =)
 
...good explanation ...thanks!

I found this took some getting used to...
The transition from regenerative braking to mechanical braking.
It's relatively smooth (on mine) certainly but noticeable.
 
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