[dBC]

what's happening if, say, one sets the drive to D- -? If you make that selection from say the D position (i.e. two pulls on the - paddle) whilst maintaining forward motion, you need to press harder on the accelerator (than say in D, let alone D+) to maintain speed,

I can't say I've ever noticed that in the EQC, and I do exactly that every time I start a journey (because I mostly drive in D-- but the car defaults to D). In my experience, whenever the Power meter is in the +ve side, i.e. the motor is propelling the car forward and consuming energy, the paddle settings are irrelevant. They only come into play when the Power meter has swung -ve, i.e. the motor is actively slowing the car and generating energy. So as I start up and drive off down the road, I give two flicks on the left paddle and notice no change to anything - until I next lift my foot off.

I also query the efficiency of cruise control, especially with route-based speed adaptation activated. The car constantly accelerates and decelerates - sometimes, quite aggressively - which I imagine would be detrimental to economy.

Yes, route-based speed adaptation was the first thing I disabled.

I think the paddles are completely ignored once the cruise control is engaged. The cruise control tell the drivetrain "I want to go descend this hill at 50 km/hr (say)" and it then applies just the right amount of regen to achieve that.. regardless of how the paddles are set. The paddles are all about what happens when you lift your right foot off, but when the cruise control is engaged your right foot is resting on the carpet, so the paddle settings don't matter.

As far as coasting goes, what coasting actually means is that the Power meter is at 0. The motors are neither propelling the car, not slowing it. Electrical energy is being neither consumed nor generated. The speed of the car is then just down to gravity, gradient, rolling resistance etc.

You can actually coast in any D setting... even D--, it just take a lot more driver effort to achieve in D--. You need to monitor the Power meter, and carefully modulate your right foot to keep the Power meter at 0. Not enough right foot and the Power meter will swing -ve, too much and it will swing +ve. That's a lot of hard word and I'm not suggesting it as a viable driving technique - far easier to just select D+ and rest your right foot on the carpet. But it demonstrates there's nothing particularly complex going on with the paddles.. they just control what happens when you lift your right foot.

 

[dBC]

I think locale plays a bit part in the answer too. All that D-Auto and route based speed adaptation relies on quality mapping data, and in Australia the mapping data sucks. @EQA-S.oz you might want to consider disabling route based speed adaptation, it can be quite dangerous. There's a spot on the A1 somewhere south of Coffs where it will do an un-commanded harsh deceleration in otherwise clear air motorway driving - it's as if someone left a roundabout on the motorway (at least in the mapping data). MB took all of about a msec to respond with "oh yeh, you should disable route based speed adaptation", so I'm pretty sure they're aware the local mapping data isn't up to the task.

 

[dBC]

In my EQA250, when I drive along a flat section of road (at urban speeds) in say D and I select D- I need to press slightly harder on the accelerator to maintain speed and press even harder if I select D- -

I did test that in my EQC400 yesterday and wasn't able to replicate it. I'm hours away from launching on a 200km motorway trip, so should have plenty of opportunity to reconfirm.

I beg to disagree, dBC. As I commented earlier, in my EQA250, selecting D+ removes any decelerative effect, whereas in D I experience a mild decelerative effect when I remove my foot from the accelerator. I like that; it's very similar to most ICE vehicles. I agree, the Power meter shows 0 when you do so.

I think we're actually in agreement even there. I potentially threw you by my weird definition of "coasting". I think of "coasting" as having the car moving, while the power meter reads 0. That's achievable in any D setting (it's just really hard to do in the lower D settings).

I can't 'coast' in my car when drive is set to D, D-, or D- -, but I can achieve a Power meter reading of 0 by adjusting my foot pressure on the accelerator.

Yes, that's all I was trying to say. I call that "coasting". I think your definition of "coasting" means you're not having to do anything with your foot. From a driver's point of view your definition makes more sense, my definition is more looking at things from an efficiency point of view. I guess what I was trying to say is there are plenty of ways making the car move "for free". Unlike in an ICE car, it's the Power meter that tells you whether the car is moving freely or not - not the position of your right foot.

Two interesting questions: whether the car uses regen alone to decelerate, or regen plus friction brakes. Perhaps it depends on the circumstances; however, when I've contemplated this I've also considered the amount of retardation taking place and in most cases I feel it's within the capability of the regeneration system (alone); i.e. similar to D-, or in some cases, D- -

Have you configured your instrument cluster to include the Power meter, if only while contemplating these questions? I find it very informative. I live at the top of a very steep hill (too steep to ride my e-bike up). When I back off completely in D-- the Power meter swings to -80% and it's really holding things back. Eventually I get to spot where I need even more slowing so gently touch the brake pedal.. that causes the Power meter to swing to -100% and things really slow down. I'm yet to find any brake dust on my front wheels even though that happens pretty much at the start of every journey. BTW, I think this is one aspect where the behaviour will vary a lot from model to model. Coming down that hill, even at -80% my Energy Flow screen is showing both motors are involved in the "braking". I'm certain different models will have different max-regen capabilities... probably somewhat correlated to how much power they have. I've got 300kW of power, you've got 140kW, so I imagine mine can do a lot more regen braking than yours - but mine is also quite a bit heavier than yours, so it all gets a bit blurred. Battery capacity and max DC charging rate might be relevant too.

Yes, my EQA250 does have mapping with quite a bit of information

My anecdote about the unexpected hard deceleration on a clear motorway wasn't from my EQC (which has even older mapping data than your EQA). It was from an EQS AMG 53 delivered new just two months ago. Presumably that has the best mapping data MBA can find, and yet still they told him to turn it off.

I'm encouraged by your positive comments about D Auto.

I don't want to rain on your parade, but I think all the folk that like D-Auto live in Europe. That same mapping data that is making route guided speed adaption unusable in Australia will also be heavily involved in D-Auto calculations. My mate with the EQS tried it and lasted all of about 5 mins. He's sticking with D and I'm sticking with D-- in my EQC. Nice that we all have the choice to tailor our rides.

 

[dBC]

In my EQA250, when I drive along a flat section of road (at urban speeds) in say D and I select D- I need to press slightly harder on the accelerator to maintain speed and press even harder if I select D- -

OK, with plenty of flat motorway to test on, I had cruise control and speed limiter off, Speedo reading a steady 100 km/hr, Power meter was reading +8%, paddles were set to D and I kept my right foot locked in the one position. I then went to town on the paddles... D-, D--, D, and D+.... nothing changed... speed stayed constant and so did the Power meter. So I think we can conclude that's a definite difference between the EQC and EQA - unless maybe it's speed related, you at urban speeds and me at motorway speeds.

Somewhat related to the topic, I'd charged the car to 100% for this trip, which I rarely do, and noticed a difference heading down my hill. I backed off completely at the usual location and the Power meter only swung to -40% (compared to -80% as described above) which gave much less "braking", then when I pressed the brake pedal it just stayed at -40%, and the pedal felt quite different. So I think for the first time ever I've used my friction brakes coming down my hill. So another criteria for how much re-gen braking you get is how much headroom the battery has to accept more energy. If the battery is at 100%, you get reduced re-gen.

 

[dBC]

perhaps with the more powerful and heavier EQC the change in setting is less apparent. Also, as you say, momentum may be a factor.

Just to be clear, the different paddle settings in the EQC are noticeably (even vastly) different so long as the Power meter is in the -ve. I don't think it's just a subtlety thing that I'm missing when the Power meter is in the +ve, I think they're truly ignored when the Power meter is +ve. TBH that's also kinda' how I'd expect it to work - given they are the re-gen settings I wouldn't expect them to affect anything when you're not re-gen'ing. I can't imagine what is going on inside the EQA to cause the behaviour you're observing.

 

[dBC]

It gives a perception of energy efficiency, but retardation requires either a couple of quick pulls on the left paddle, or application of the friction brakes, or both.

Do you mean application of the friction brakes, or do you man application of the brake pedal? In most EVs (but notably not Teslas) application of the brake pedal just increases re-gen braking - you should be able to see that on the Power meter. Further application of the brake pedal will invoke the friction brakes but at least on my EQC you can kinda' feel that transition as the pedal feels different once the real friction brakes get involved with the slowing down process. So applying the brake pedal mightn't be as bad for efficiency as you think.

In my EQC experiments, I've not noticed any significant difference in efficiency using the different D settings. Ultimately the same amount of re-gen braking happens, I just have to do different things with my feet to make it happen.

 

[dBC]

The first one is the one you want.... it'll swing clockwise from 0 when you're consuming energy and anticlockwise from 0 when you're re-gening.

If you select D+ for example, and take your foot off the accelerator completely you'll see it drop to 0. If you then touch the brake pedal you'll see it swing negative to indicate that the brake pedal has invoked re-gen braking for you.

If you do the same in D, it'll go slightly negative when you take your foot off the accelerator, showing you there's a little re-gen going on. If you touch the brake pedal it'll swing further negative.

Ditto for D- and D--.

 

[dBC]

No worries, hopefully you'll find it informative. If you want to go all out, you can also select the "Progressive" instrument cluster style. I'm not a big fan of that style, but for the purpose of these experiments it has the advantage of actually giving you a numeric readout on the Power. That's how I was able to quote the +8% above.