[HybridLA]

I saw a thread about this from 2023 but wanted to resurrect the discussion given the additional 2 years of drivers' experience.

If one is agnostic to which mode (D or B) what mode or combination of modes (like B in city and D on freeways) do you think achieves maximum miles/kWh efficiency overall?

[exxxviii]

Originally Posted by HybridLA

If one is agnostic to which mode (D or B) what mode or combination of modes (like B in city and D on freeways) do you think achieves maximum miles/kWh efficiency overall?

They are the same. They just use different methods of invoking regenerative braking. In D mode, you have the push the brake pedal to regen. In B mode, you simply back off the accelerator pedal to invoke regen.

I prefer D mode on highways because it is easier and smoother for me to regulate speed with coasting. But around town driving or any kind of slow/stop and go is pure B. I love one-pedal driving!

[HybridLA]

So you are writing that whether one uses (1) D mode and manual braking OR (2) B mode and regen braking to come to a complete stop you would be sending the same amount of kW back to the car?

[Paladin1]

There are threads on this, recent and earlier:

https://bmwi.bimmerpost.com/forums/s...ghlight=B+mode

https://bmwi.bimmerpost.com/forums/s...ghlight=B+mode

The short answer is, it doesn't matter (as far as efficiency). Personal preference is the primary factor on what drivers choose.

[exxxviii]

Originally Posted by HybridLA

So you are writing that whether one uses (1) D mode and manual braking OR (2) B mode and regen braking one to come to a complete stop at a light you would be sending the same amount of kW back to the car?

Yes, exactly.

[Paladin1]

Originally Posted by HybridLA

So you are writing that whether one uses (1) D mode and manual braking OR (2) B mode and regen braking one to come to a complete stop at a light you would be sending the same amount of kW back to the car?

There is no exclusive "manual braking" in the iX. The iX (and BMW's other EVs) use blended braking - regenerative braking is the default when you press the brake pedal, unless and until the car senses it needs to come to an immediate stop and uses the mechanical brakes. Regenerative braking is used the majority of the time in either mode (if you need to come to a stop using B mode faster than OPD and you press the brake pedal, it will be in regen mode until you press hard enough to completely stop). BMW's blended braking is essentially transition-free as far as driver perception.

[ggalanis]

Originally Posted by HybridLA

So you are writing that whether one uses (1) D mode and manual braking OR (2) B mode and regen braking one to come to a complete stop at a light you would be sending the same amount of kW back to the car?

TLDR no real noticeable difference.


The only difference is how easily you can coast in the adaptive mode which you can only have in D.

You may be able to coast in B as well (I don't use it often enough as i don't like 1 pedal driving in normal driving but i think you can do it at the right throttle level), however given it is harder to do, you may do less of it in B mode. Same as if you are using the brake pedal to slow down you may be more likely to push past the Regen point and use the friction brakes more than someone doing 1 pedal driving.
Coasting is considered more effective than using any Regen as it uses all the kinetic energy to move you forward. When you Regen instead, you capture some % of it but there are losses.

So the efficiency effect of your choice of D vs B will likely be outweighed by whether or not you chose to go to the bathroom or not before your drive.

[HybridLA]

That's super helpful information. Thanks everyone!

[Windshieldfarmer]

I use D mode with the adaptive braking setting. That is fantastic technology as it anticipates when I need to stop based on traffic/navigation and selectively applies regenerative braking for me as needed. BMW knocked it out of the ballpark with this feature.

[ggalanis]

Originally Posted by Windshieldfarmer

I use D mode with the adaptive braking setting. That is fantastic technology as it anticipates when I need to stop based on traffic/navigation and selectively applies regenerative braking for me as needed. BMW knocked it out of the ballpark with this feature.

It works OK in most situations but I find that in city traffic it has a tendency to brake too early and find myself having to compensate with the throttle pedal to make it behave as I want. I would prefer a mode with no regen on liftoff at all.

[LVBMW]

Originally Posted by ggalanis

It works OK in most situations but I find that in city traffic it has a tendency to brake too early and find myself having to compensate with the throttle pedal to make it behave as I want. I would prefer a mode with no regen on liftoff at all.

I thought you could turn off the regeneration entirely?

[ggalanis]

Originally Posted by LVBMW

I thought you could turn off the regeneration entirely?

nope. You can set it to high, med, low, or adaptive.
Some days when it really bugs me I *almost* change it to low instead of adaptive... and then the road opens up, I end up with more space before the car in front and it stops being on my mind.