Elevation and range

[Tommm]

My daily commute of 35 miles each way starts at 6400 ft towards Denver at roughly 5280 ft so about 1000 ft difference. Up and down on the highway going 75-85+ mph. Normally I get to work at 80% battery. When I get home at night from work I am at 45-50% battery. If that helps.


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That's similar to what my suitemate experienced with his Tesla going to Vail. The Mini store is hosting the BMW clubs autocross banquet tomorrow/Sat evening. It will be nice to see some serious autocrossers recognized for their efforts.

 

[GetOffYourGas]

At what battery percentage does regen resume its assigned duty?

I haven’t measured this per se. Normally after a few miles (and two lights) I get on the highway and it is moot. But based on memory/feel I would say somewhere between 90-95%. I’ll have to pay closer attention.


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[MichaelC]

I read or heard somewhere that the transition to "real" regen is 98%. I'm fuzzy about whether it's at 98% or below 98% (e.g. at 97%).

 

[insightman]

I haven’t measured this per se. Normally after a few miles (and two lights) I get on the highway and it is moot. But based on memory/feel I would say somewhere between 90-95%. I’ll have to pay closer attention.


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I really can't feel the difference. And I can't come up with a test to measure the difference. I pop then let off the accelerator going down my short driveway and my SE stops before the end of my driveway regardless of the battery's state-of-charge.

For those who do feel a distinct difference between regen and pseudo-regen, it should be easy to tell at what battery SOC percentage the transition occurs. Or is the border condition indistinct where it can feel like true regen one moment and pseudo-regen the next?

 

[Puppethead]

When driving, I always take my foot off the "go" pedal for full regenerative braking a specific distance before an intersection to come to a stop at the right point. The first stop sign from my house is just over two miles away, and I'm still at 100% SoC by the time I get there. I swear the "regenerative braking" feels different before that first intersection, and it seems to take longer to get to a stop. I frequently have to use the friction brakes to stop in time.

 

[polyphonic]

I really can't feel the difference. And I can't come up with a test to measure the difference. I pop then let off the accelerator going down my short driveway and my SE stops before the end of my driveway regardless of the battery's state-of-charge.

For those who do feel a distinct difference between regen and pseudo-regen, it should be easy to tell at what battery SOC percentage the transition occurs. Or is the border condition indistinct where it can feel like true regen one moment and pseudo-regen the next?

Even at 95% it feels different. Ambient temperature could also play a role. Try charging to 80% for a few days and then going back to 100%. You might notice it then.

 

[MichaelC]

To really test where the transition is, set the "onboard computer" section of your instrument cluster to display instantaneous consumption. When under regenerative braking, that value will be negative...but in a rather unintuitive way--it shows how many miles you would have to retain that amount of regenerative braking to charge 1kWh (assuming your consumption is shown as mi/kWh). The closer to zero that number is, the more energy you're gaining from regen braking.

If I recall correctly (which I may not), my SE peaks at -1.8 mi/kWh when maximum regen is available. Even when the battery is "full" it will show a non-zero negative value under regen instead of "--" (or infinity), but a greater negative number than -1.8 (meaning it would take a much longer distance to recoup 1kWh). But I always forget keep an eye on that number after a full charge to see when the change-over happens, and it will be a few days before my next full charge...

 

[insightman]

Even at 95% it feels different. Ambient temperature could also play a role. Try charging to 80% for a few days and then going back to 100%. You might notice it then.

I charge only a couple of times a week, so most of my driving is at 80% SOC or below. So twice a week I get to experience pseudo-regen braking. I remember my surprise months after taking delivery of our SE, when I realized there can be no regen braking at 100% SOC. You more sensitive drivers figured that out right away.

 

[MichaelC]

If I recall correctly (which I may not), my SE peaks at -1.8 mi/kWh when maximum regen is available.

Correction: Maximum recuperation on the high regen setting is -0.8 mi/kWh. On the low regen setting, it's -1.6 mi/kWh.

I will leave the instantaneous consumption reading on my instrument cluster and try to pay attention to it the next time I drive after a full charge.

 

[Carsten Haase]

Correction: Maximum recuperation on the high regen setting is -0.8 mi/kWh. On the low regen setting, it's -1.6 mi/kWh.

I will leave the instantaneous consumption reading on my instrument cluster and try to pay attention to it the next time I drive after a full charge.

I've seen that same -0.8mi/kWh as a stable maximum around ~30mph but it depends on speed (at higher speeds you'll never hit -0.8).

The limit is really a kW value (current into the battery) but we can't see that. The kW gets translated to mi/kWh by dividing your speed by it. The kW limit is also affected by battery temp so the SOC that the brakes are activated at will not be completely consistent.

The easiest way to determine if the brakes are being used during regen (other than driving with the window down) is to actually use the brakes yourself. If the car has already been using the brakes, the pedal will immediately feel hard rather than the usual couple inches of squish

 

[Rexsio]

My daily commute of 35 miles each way starts at 6400 ft towards Denver at roughly 5280 ft so about 1000 ft difference. Up and down on the highway going 75-85+ mph. Normally I get to work at 80% battery. When I get home at night from work I am at 45-50% battery. If that helps.


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Every body looks different with SE experience my look is only milage display as I’m driving 37 miles each way I always get home with 60 miles in my tank but I’m on flat road no difference in elevation and going fast and slow in traffic I’m always that range in milage SE is consistent.But if I drive locally for week or two driving 2-5 miles daily I’m in about 100 miles only.

 

[MichaelC]

I've seen that same -0.8mi/kWh as a stable maximum around ~30mph but it depends on speed (at higher speeds you'll never hit -0.8).

The limit is really a kW value (current into the battery) but we can't see that. The kW gets translated to mi/kWh by dividing your speed by it. The kW limit is also affected by battery temp so the SOC that the brakes are activated at will not be completely consistent.

That all makes sense and is consistent with what I have seen. All my tests have been in the 30-45mph range.

With a freshly-charged battery, I could see a peak of -1.0 mi/kWh at 100% state of charge--but only very briefly and after a very slow ramp-up. At 98%, I could hit -0.8 mi/kWh but it was similarly a slow approach. Below 98%, it was a little easier to hit -0.8 mi/kWh.

The easiest way to determine if the brakes are being used during regen (other than driving with the window down) is to actually use the brakes yourself. If the car has already been using the brakes, the pedal will immediately feel hard rather than the usual couple inches of squish

I like the window rolled down method, especially if the rotors a little rusty so it's easier to hear the brakes engage.