Does any EQS owner have data points on how far their brake pads and rotors lasted? Read on another forum that they needed replacing at less than 10K.

 

You heard wrong. They last a lot longer than that.

 

How long do they last?

 

Much longer than they would without regenerative braking.

 

Are you able to quantify the lifespan, in terms of miles or kms?

 

One can't quantify this - if you do virtually all highway miles, then the rotors and pads would last a lifetime on an EQS. I believe the brakes switch to friction braking only above ~ -7Gs. For less braking, it is all done by regenerative electric braking using the existing motors.

 

If you have a RWD EQS I would expect front rotors and pads to wear faster than on the AWD models. If you use the lane keep feature and the assisted steering feature with cruise control you will see a lot of brake dust on the rear wheels.

 

Nope, but it's long enough of a lifespan that contemplating the miles or kilometer is a monumental waste of time. If I still own the car years from now when they might need changing, I'll probably spend less time changing my pads than I've spent reading this thread.

 

Exactly. On some EVs corrosion rather than wear has been a more common problem.

 

I've been doing a little informal experiment since driving my car, and I've done some research on regenerative, dynamic, and hydraulic (friction) braking which are utilized in the EQS and other EVs.

Putting your car in strong regen, the car comes to a stop using the first 20% (single motor) - 40% (dual motor) charge before the dynamic braking kicks in and brings the car to a stop. I am speculating on the percentage, but I think 20% charge is probably Mercedes set point for regeneration acceptance. In this scenario, you let go of the accelerator pedal and not step on the brake pedal under strong regen. No hydraulic or friction braking is used; therefore, your brakes and rotors are not used. The strong regen mode will best preserve your brake pads and rotors.

Under Normal regen, the EQS only used the regenerative function (20% charging) when you let go of the accelerator pedal. If you want the car to stop, you have step on the brake pedal which is actually using the hydraulic braking system. Your pads and rotors will wear depending on how much and how aggressive you want your 6000 lbs vehicle to stop.

Under no regen, you have to use the hydraulic brakes to stop the car just like what we have done for the past 100 years.

This little short video can help explain some of the tech behind dynamic, regenerative, and hydraulic braking in an EV.

 

On the EQ on strong regen, when you liftoff, full regen is applied. Fom there, if you press the brake pedal its pure friction (since all regen is already in effect) Thats why the pedal moves by itself, the amount of pedal travel equates the amount of braking power being applied by regen. Most reviewers dislike the full regen on the EQS. Personally, once you get used to it, it makes complete sense. When using max regen you should not need to use the brake pedal except in an unexpected situation. You learn to brake early by lifting of the accelerator and then basically roll into a full halt using the accelerator. In effect you have to learn a completely new way of coming to a stop, but once you learn it you wonder why anyone would do it differently!
on normal setting the brake pedal behaves like on any other Merc I have owned, no excessive travel or any other vices. That said the brakes on the IX 50 I drove were better in feel but it wasn't all that different, just a more progressive feel when driving hard. Something that is true of BMW and Merc brakes regardless, even AMG's. BMW's in general, like Porches have the best "feeling" brakes on the market
Mercs AMG's in particular can provide similar braking performance but not "feel".

 

At the time that I traded in my Tesla Model S (62k miles with strong regen braking on at all times) I had never needed either rotor or brake pad service during my 5½ years of ownership.

 

My BMW F02 went 104K miles before I needed new front brakes/rotors. The rear needed new brakes/rotors at 90K. All OEM products. In my recent test, I drove the EQS under normal regen., and after a week, the rims have brake dust galore. I was surprised. The following week, I drove with strong regen, and the dust was to a minimal. The downside to driving with strong regen is the accelerator pedal is stiffer, and it makes your ankle/foot more tired. The week after, I drove with modulation between strong, normal, and no regen braking mode based on traffic conditions. Brake dust was to a minimal too.

Now, I find myself braking with the paddles on the steering column more than the pedal on the floor. The DOWN and UP label is not intuitive at first, but if you think like downshifting and upshifting "effects" on your speed (tranny on your ICE without accelerator pedal), than it makes a lot of sense. My HUD also has the indicators too, so that helps with knowing the current regen mode and the power/charge percentage without looking down on the dash. The other advantage is that I drive with 2 feet most of the time, So, I can feel when the brake pedal moves due to regens.

C400 is right on. We have to relearn the braking system before we can comfortably push these cars to the limits, or at least not freak out with spirited driving. You hit triple digits in no time, but the nervousness is that lack of speed control due to the free wheel of no regen, The closest to ICE coasting is normal regen. You then have to rely on hydraulic braking to slow down on curves because the strong regen mode makes you feel like you're always fighting the car for power and slowing down to early if you are not used to it.

 

Hello, this information is incorrect. Pressing the brake pedal will use regen, not friction brakes, unless you exceed more than a certain amount of G's brake force.

The brake pedal is fully brake by wire. It does not matter what regen mode you use. When you apply the brakes using the brake pedal, the vehicle determines how much regen to apply and how much friction braking to apply. It only activates the friction brakes under hard braking. Using the brake pedal will regen just like using Strong Regeneration on 1-pedal mode.

If you switch to the Classic gauge screen, there is a power meter that shows you when the vehicle is regen-ing and how much. You can see exactly where the point is in the brake pedal the vehicle switches to friction brakes if you watch this gauge while using the brake pedal.

 

Indeed. However you are not getting the point. On full regen you get the full amount of regen when you lift of the accelerator you dont get any addition of friction (hydraulic) until you press the brake pedal. When you press the brake any additional braking power besides what regen is already providing is friction. If you don’t press the brake pedal, any deceleration you get is from the motors, not the brakes proper.

 

I was excited to have someone prove my observation inaccurate (rather than incorrect), and PROVIDE one or more links to Mercedes technical documents that prove what you say is completely accurate. However, I am disappointed that you only provided a mere observation, aka a gauge, at this point, which makes you a blind mouse like most of us here trying to ID the elephant.

Let me elaborate. I have the AMG version with the energy flow animation in the center screen, and performance gauge on the driver dash and HUD. I can see what the EQS reports out with Power/Charge percentage and among other information about the front and rear motors and suspensions. We know that with electronic braking, or brake by wire, the system still uses the hydraulic friction brakes to reduce the speed of travel of the vehicle. How much friction braking is used and in which mode is the question we are trying to answer for the purpose of determining the life expectancy of the EQS rotors/pads.

In no regen mode, step on the brake pedal, and the EQS indicates that the charges can go up as high as 99% depending on how much pressure "you" put on the brake pedal. I believe the charge percentage in this mode is misleading and that the reading is only a byproduct of a brake by wire system. When you depress on the brake pedal, the EQS will ONLY use the regen of 20% (aka normal regen mode) as long as you modulate your braking to maintain the 20% charge. Anything higher than 20% is all friction braking in no regen. mode. There is no dynamic braking involved. And 20% charge is almost like coasting to a stop by a normal ICE engine locked to a Drive mode tranny. That is my theory with braking in no regen mode. Since keeping the 20% charge is so short in a typically slow down to stop traffic, MB calls it no regen (aka no recuperation) mode. No regen mode without braking intervention is like having an ICE coasting in Neutral tranny mode.

Under normal regen. the System will maintain the 20% charge for you using reverse torque. Should you apply more braking pedal, no dynamic braking is applied despite charge % indicator increasing above 20%. Hence you are using the friction braking beyond the 20% charge indication. Possible evidence: In normal regen. when I release the accelerator pedal, there no movement to the brake pedal that I can feel. You may want confirm this with your own experience and report back. This tells me that the motor(s) has reversed torque to convert kinetic energy to electric energy to send back into the system (battery). Why only 20% or maybe 40% with dual motors? You can find several articles that explains more in details about overloading or overheating the system. In any case, this is true regenerative braking.

Under strong regen. the 20% charge applies, but beyond the 20% (or 40%), DBR, or Dynamic Braking Resistor, comes into play. Read this article to educate yourself on DBR.
https://www.dpaonthenet.net/article/...aking%20system.
The general term is rheostatic, or dynamic braking. In strong regen mode, true regen kicks in follow by dynamic braking which the EQS system depresses the brake pedal in an effort to accurately simulate the pedal movement positioning. I dare to say that dynamic braking in the EQS does not send electric energy back to the system. Rather, it dissipates the heat for other functions. Friction braking ONLY comes in when "you" depress the brake pedal because you require shorter stopping distance. Friction brake is also applied at the moment of complete stop (hold function in case you are in an incline/decline). This is evidence that when I drive with strong regen. there are substantially less brake dust then in no regen or normal regen mode. The only drawback is a heavier accelerator pedal on long drives.
In Intelligent regen., you let MB and the EQS computer decide on how to stop the car.

Unlike Tesla with only one option of one pedal driving, MB gives you the different modes as a luxury and the ability to choose how you want to drive your EQS. Why in the world would they invest in paddle shift on an EV? Because they're Germans and it's the luxurious thing to do. With different regen modes, I can choose to drive my EQS AMG anyway I want. I do wish I got the ceramic brake option. It would be much cheaper to get it from the start than putting it on later. So when I don't want lots of brake dust, I paddle shift between the different modes depending on the traffic condition ahead. It's like transmission shifting.

That's my blind mouse feeling this elephant in the room.

 

Indeed. However you are not getting the point. On full regen you get the full amount of regen when you lift of the accelerator you dont get any addition of friction (hydraulic) until you press the brake pedal. When you press the brake any additional braking power besides what regen is already providing is friction. If you don’t press the brake pedal, any deceleration you get is from the motors, not the brakes proper.

 

It’s pretty simple, no need to overthink or over complicate anything.

If you press the brake pedal gently, you will be using all regen braking. If you brake hard, you are using regen and friction brakes together.

The end.

https://www.mercedes-benz.co.uk/pass...e-brake-system

 

I remember mercedes has a video said that no matter under which mode, when you step on brake, it will use electric motor to recuperation, once over the maximum recuperation, physical brake will kick in.
it apply to all EV.
if it doesn't apply to all EV, it apply to Tesla, and mercedes is using Tesla technology. their brake rotor, is same as Tesla model 3 model Y model X. as 1st gen of Mercedes EV b-class is built with Tesla.

Edit: I can't find the video but here is the Porsche said how recuperation works. it apply to all EV. the only difference is Taycan can recuperate much more energy than all other EV
https://newsroom.porsche.com/en/2022...403-28723.html

 

The most any EV can theoretically regenerate is the maximum DC current it can charge. For example on the EQS its 200kw.

 

I googled, EQS 4matic recuperation output is up 290kwh, AMG53 is 300kwh

 

You're right about Mercedes but Teslas are different. In Teslas, the brake pedal is connected to the friction brakes only. All regen comes from letting off the accelerator pedal. If you press the brake pedal in a Tesla, you are using friction brakes 100% of the time.

 

Not correct

Single-motor EQS 450 can regen up to 186 kw.

Dual-motor EQS 450/580 can regen up to 290 kw.

Dual-motor EQS AMG can regen up to 300 kw.

 

The battery can only accept 200, if there is any extra it must be lost as heat somewhere. That can only be a peak regen of a few seconds.

 

thanks for correcting me. maybe that is why their one pedal brake is more aggressive.