Warm Weather Range and Regen Behavior

[Stretch2727]

I took my first test drive today in the B class. May take the plunge.

I would like to get a feel for the range people are seeing now that the weather is a little warmer.

I am just surprised that the B-Class appears to be so much less efficient that the other EV's on the market. I just returned a Ford Focus electric off lease and would like something with a little more range as there were many trips where we would not take the Focus due due to range. In theory the B class should have 50% more range than the Focus but in reality it is only 14% better. The MB is 10% heavier than than the Focus. I am just surprised 10% more weight accounts for 25% less efficiency than the Focus based on the EPA ratings.

The other thing I noticed is the regen is not very consistent. If was in regen and pressed the accelerator slightly, then backed off the accelerator the car seem to freewheel. Then I had to use the brake to slow down. Not sure if it was in Auto D or not. I just prefer the consistent heavy regen of i3 and my Focus in low "gear". Anyone notice this?

 

[phototrek]

Auto D makes all the difference. If you're not sure if you were in Auto D then that makes it hard to answer.

In Auto D it will regen in such a way that it keeps a safe distance. If you don't like the inconsistent behavior, just flip the left shift paddle and you're in D-, which is consistent with your Focus' "L" setting. Or flip the right paddle, and you're in what's "D" on your Focus.

Personally I drive my Focus always in "L" as that allows one pedal driving, but it's more jumpy for passengers who don't immediately expect what your foot is about to do.

 

[TheStig]

In D Auto the regen level varys depending in condition. Assuming the car you drove or buy has the radar recouperation package and paddle shifters......and you want that....

Lifting off the accelerator will regen more and more the closer you are to the car in front of you. If there isn't anything in front of you in radar range it will coast or very lightly regen.

In addition to that there is a tilt sensor that will regen lightly if you lift off on a down hill slope. Steeper the hill and more speed the car naturally picks up and the harder that regen will become.

Lift off going uphill I'd bet it coasts unless there is a car close in radar range.

 

[JeffRay]

Stig,

Your post very informative. I have not learned to fully optimize despite owning car for almost 120 days. But I agree, I was coasting a long way today down a slight incline without feeling any resistance vs. immediate slow down in stop and go traffic.

 

[Stretch2727]

Phototrek,

-Yes the car had the radar and the paddles. I am pretty sure it was in Auto D, so this likely explains the behavior.

-Since you also have a Focus and the B Class what is the difference in range you see between the 2? A least your environment and driving style is consistent between the 2 cars. The posting for ranges I see are so varied likely due to climate and driving style it is hard to draw any conclusions. I also know what I could achieve on the Focus so it will be a good indicator for the B Class.

 

[JeffRay]

Stretch, I heard the MB likes to say, "only the best". What that means in our case is no cutting back on safety and features available on gas powered B-Class. So my conclusion is that they plunked their car on top of the battery pack and did as little fiddling as needed. Contrast that with what BMW invested in the i3, a purpose built vehicle. The MB folks were satisfied with 86 mile indicated range under average conditions. The fact that their battery pack delivers sub-par mpKwh is not something they optimized to I would guess. In three years, I am hoping for a better range performance in their next gen electric.

 

[beker45]

Hi B-ED friends,

i'm from Austria. I own the new facelift version of the B-Class with RangePlus.

Last Tuesday i was able to drive over 166km (103miles) with rest 42km (35miles).
I drove from Bregenz (Austria) to Augsburg (Germany)

Speed: 95 km/h (59miles/h)
Temp:11,5 Celsius (53 F)
Heating: NO
Seat-Heating: YES (Level 1)

 

[Tonglaji]

Hi B-ED friends,

i'm from Austria. I own the new facelift version of the B-Class with RangePlus.

Last Tuesday i was able to drive over 166km (103miles) with rest 42km (35miles).
I drove from Bregenz (Austria) to Augsburg (Germany)

Speed: 95 km/h (59miles/h)
Temp:11,5 Celsius (53 F)
Heating: NO
Seat-Heating: YES (Level 1)

was your route mostly downhill?

 

[beker45]

Hi B-ED friends,

i'm from Austria. I own the new facelift version of the B-Class with RangePlus.

Last Tuesday i was able to drive over 166km (103miles) with rest 42km (35miles).
I drove from Bregenz (Austria) to Augsburg (Germany)

Speed: 95 km/h (59miles/h)
Temp:11,5 Celsius (53 F)
Heating: NO
Seat-Heating: YES (Level 1)

was your route mostly downhill?

You can have a look on this site: http://www.goingelectric.de/stromtankstellen/routenplaner/142946/
You have to click 'BERECHNEN' to see elevation of the route.

From 400m up to 720m, then down to about 460m

 

[mikegerard]

The other thing I noticed is the regen is not very consistent. If was in regen and pressed the accelerator slightly, then backed off the accelerator the car seem to freewheel. Then I had to use the brake to slow down. Not sure if it was in Auto D or not. I just prefer the consistent heavy regen of i3 and my Focus in low "gear". Anyone notice this?

Light braking is really regen. The brakes only engage in heavy breaking. One reason I prefer this is that it turns on my brake lights.

 

[Stretch2727]

Hi B-ED friends,

i'm from Austria. I own the new facelift version of the B-Class with RangePlus.

Last Tuesday i was able to drive over 166km (103miles) with rest 42km (35miles).
I drove from Bregenz (Austria) to Augsburg (Germany)

Speed: 95 km/h (59miles/h)
Temp:11,5 Celsius (53 F)
Heating: NO
Seat-Heating: YES (Level 1)

Was this using the range extender? Are you saying the total range was 138miles (103+35)!!!

 

[Stretch2727]

I want to know the real world range people are seeing on the B-Class as the EPA rated range and efficiency seems out of wack to me.

I took the EPA city MPGe rating and compared them on the chart below to the curb weight for several EV's. You should expect a relatively linear relationship. Higher weight leads to lower efficiency as the chart shows. I used the city MPGe ratings as weight is the main factor in lower speed stop and go driving for efficiency. The Tesla's weigh even more but manage to beat the B-Class in city MPGe efficiency. Again I am just using city MPGe to take out the aerodynamic factors that mainly come into play on the highway.

As you can see the B-Class and the Smart EV (both Mercedes products) are well below where they should in city efficiency given their weight. (They are well below the linear line where most other cars seem to fit nicely.) Interesting that all the ICE converted cars are slightly below the line (except the Fit EV) and all the pure electric are above (higher efficiency). This is pretty minor gap compared to the gap on the B-Class and Smart EV. If you factor in weight, there are not nearly as many variables in and electric car as an ICE car. No major transmission differences, engine displacement and engine thermal differences or other variables to cloud the picture. A large percentage of the energy should be converted to forward motion as there are no heat losses etc. The main factor in city driving efficiency should be the weight of the car.

So my conclusion is one of the following is true:

1. They are using the wall to wheels power consumption that is claimed is being used on the mpKwh display in the B-Class to calculate range. Further they are derating the MPGe by this factor 2 times instead of once as it should be done. If is true, the B-class range is really 15-20% more than advertised and the efficiency/range was mis-calculated. The battery capacity and hence range is not effected by the charging losses in which they are trying to account once the energy is in the car.

2. The battery thermal management or other accessories in the car are eating up a lot more power than other electric cars.

3. B-Class drivetrain is not optimized and using much more energy than other EV's. Possible, but not likely as electric motors do not have significant efficiency differences.

4. Maybe the regeneration is very inefficient and there are high losses pushing energy back to the battery. Again possible, but very unMercedes and unGerman engineering.

5. Tesla hid a software bug so Mercedes would not have true a triple digit range electric car. (I don't think this true...but just trying to think of every possible reason).

I have seen other posts blaming the weight of the B-class for its low efficiency and relative range. I just don't think the weight is completely to blame as the chart shows.

I am hoping it is number 1 as I would like to seriously look at the B-Class, but am somewhat turned off by the disappointing efficiency and range given the size of the cars battery.

Let me know if anyone has a solid explanation for this huge difference in the ratings on the b-Class.

 

[northernlights]

Well I had an opportunity to test the range in warm weather. In my first week of ownership I had a birthday to drive my son to at a theme park that was 43 miles away according to google maps. I figured I'd try to make it round trip since the car is supposed to have about an 85 mile range. (I have a 2014 without the range extender). Since I hadn't gotten my in home level 2 charger installed yet, I was relying on a long charge on the level 1 charger, that ended up having the car at only 94% SOC when it was time to depart. I was a bit concerned at this point about my ability to make it round trip, so I drove very efficiently (no A/C, 60 MPH cruise control on the highway). It was 86% so it was a bit uncomfortable in the cabin. When I arrived at the destination I had travelled 36 miles (my route must have been shorter than what was posted on google maps) and 64% SOC. This trip used 30% of the charge, so it extrapolates to a 120 mile range. On the way back it had heated up to 96 degrees, so feeling much more confident in my ability to get back, I used the A/C intermittently (about 50% of the time) which kept things comfortable. I again drove efficiently at 60 mph with cruise control. The return trip took 37 miles on the odometer and the SOC went from 64% to 27%. That return trip extrapolates to 100 miles of range from a full charge.

Based on these results, I imagine the maximum range on a hot day is about 120 miles with ultra efficient driving, with 85 miles probably realistic for carefree driving and 100 miles being very doable with careful driving.

 

[tom]

Stretch ... could you add RAV4 EV to your chart above please.

Northernlights .... that's great range you got! Let's hope others are this good as well.

 

[Stretch2727]

Stretch ... could you add RAV4 EV to your chart above please.

Northernlights .... that's great range you got! Let's hope others are this good as well.

I will add the RAV 4 to the chart above. Do you know the weight for the RAV4 as sometimes I need to dig for this information? The "fuel" economy is easy to get from the EPA website.

The point with this chart is that the MB is underrated for efficiency and range. The car makers do their own EPA ratings based on standard EPA tests...I am convinced MB somehow screwed up or was very conservative, at least compared to other EV manufactures. I wanted to buy the car only if regularly it could go 100 miles on a charge.

Now that I have the car I know I regularly can go 110 miles....120 in ideal conditions on standard charge. This is 25-40% over the rated EPA range of 87 miles.

My previous Ford Focus Electric in ideal conditions would go about 85 miles, this is only 11% over the stated range of 76 miles. Again this is ideal conditions, most times the real range was between 60 and 80 miles which matched the rated range of 76 miles.

Another indicator the range is wrong is the usable battery size on the MB is about 50% larger than the Ford. If I take the Ford's range (76) and multiply by 1.5, I get 114 miles. Just about what many people (including myself) are seeing from the MB. This also points to the MB efficiency being close to the Fords 100 MPGe, not 85 MPGe as stated.

If the EPA range rating and the dash GOM showed the car could do 100+ miles on a charge I think they would be selling a whole lot more of them than they are right now.

 

[tom]

2012-14 RAV4 EV curb weight is 4032 lbs

 

[hybridbear]

In reality are owners seeing the higher energy consumption that the lower EPA rating would indicate? In our Focus Electric we average just over 200 Wh/mi (just under 5 mi/kW) in city driving. Would the BCED be much worse? We're considering it as a possible replacement for the Focus when its lease ends.

 

[Stretch2727]

In reality are owners seeing the higher energy consumption that the lower EPA rating would indicate? In our Focus Electric we average just over 200 Wh/mi (just under 5 mi/kW) in city driving. Would the BCED be much worse? We're considering it as a possible replacement for the Focus when its lease ends.

In the warmer weather it is just slightly worse than the Ford Focus Electric. I have not had the MB yet in the cold as I just got in April.

My average for my former Focus Electric over 20K mikes was about 260 watts per mile. (Not as good as you...) In 2500 miles, my MB average consumption has been about 275 watts per mile.

This is only 5-6% worse. The EPA ratings are almost 17 -20% worse for the MB.

Because of the much bigger usable battery 28 kW versus 18.5, I see easily over 110 mile range in the MB if I take it easy. I could never get close to this in the Ford. About the best I ever did in the Ford was about 85 miles.

The GOM (Guess or Meter) is way low in the MB where as in the Ford it was alway very close to the range based on my recent driving. The extra range of the MB makes it far easier to use on longer trips.