Drive efficiency question for owners

[Zythryn]

Hey all, I was hoping I could get some input from owners.
The epa site lists the efficiency of the B Class at 40kWh/100 miles.

Is that accurate in your experience?
Or is this another example of the epa numbers not telling the whole story?

Has anyone been tracking their Wh/Miles over the summer? I realize that nosedives in the winter for those of us in the north.
I'm looking to get as efficient an EV as possible and would love to consider the B.

Many thanks!

 

[BCKator]

The BMW i3 is the most efficient EV at the moment as I understand it so, if that is your only criteria, don't consider the B.
The B is one of (if not the most) inefficient EVs out there, due to its weight/steel-body and host of luxury/comfort features.
Max efficiency was not my overriding concern and there were lots of reasons for me to choose the B over the i and I don't regret my decision.

The B reports mi/kWH and that EPA number works out 2.5 mi/kWh. I'm able to get that doing 100% city (stop/go) driving moderately aggressive. You can get much higher doing mostly highway driving.

 

[wtzouris]

In the cold New York winter I am averaging 2.3 - 2.5 mpkWh. With a regular charge you have 28 kW of useable energy and with an extended charge you get 31.5 kW. Multiply 2.4 mpkWh times the useable kW: ** Except it has been suggested that that number should be multiplied by 1.2 because Mercedes calculated the mpkWh meter as WTW (Wall to Wheels) to account for charger efficiency. So 3.0 mpkWh is really 3.6 mpkWh.
That works out to 68-76 miles of range. In order to achieve these efficiencies I am driving with minimal or no a/c (heating) system, instead using heated seats, heated windshield, E or E+ mode, Cruise Control, D (Auto) radar regeneration mode. I am more conservative for my trip to work and less conservative driving home.
I got the car 12/31/14 so I don't know about summer, but these have to be the worst conditions for efficiency. I would not consider a 2014 model without the extended range function, all 2015 models have it. I'm sure with temperate weather you could get the efficiency up to 3.0-3.2 mpkWh which could get to the 100 mile mark with the range extended charge. But then with summer and A/C usage I bet it will be back down again, not as bad as winter. The EPA range of 87 miles is probably a good overall average number. Crazy that the car's overall range can vary from 68 to 100 miles. And whatever you do, don't pay any attention to the car's remaining range calculator, aka GOM, aka Guess-O-Meter. It's always off by 8-20 miles, constantly re-calculating. It might suggest an overall range of only 47 or 51 or 57 or 61 miles on a cold morning but as you get going and do some highway driving it adjusts. I drive 29 miles each way and once I didn't charge at work and after 58 miles (on an extended charge, 25 degree day) I still had 31% battery left -- my lowest SOC (state of charge) to date.
That would have produced a 76 mile range. With a regular charge I would have been down to 21% remaining. A general rule for my first month of ownership has been 7 miles travelled for every 10% state of charge. Extended charge gives you 110% overall since the meter stays pinned at 100% for the first 7 miles of travel. Hope that was helpful. If you can handle 68 mile minimal range with driving smart and not using Sport mode or anything extreme this is a great BEV. And try to charge all day at work so you don't feel limited by the range.

 

[JeffRay]

If you google Mercedes B-class and Consumer Reports, you will get their article about relative efficiency. That being said, range wise, Mercedes ranks behind the Tesla for range. About the same as the i3 (ex their range extender). Not sure about other all electrics.

Ah to live and work in sunny San Diego and have a home plug in. (We are expecting around 2 ft of snow overnight). Was there two weeks ago and driving an Impala rental with 50K+ miles wondering what driving my Be would have been like. I returned the rental car having put 46 miles on it driving up and down I-5. The Be would have been wonderful that day (so would my roadster). Sigh.

 

[wtzouris]

BCKator is right -- if efficiency is fundamentally important to you the i3 BEV is the leader, it is super light and only carries a 24 kW battery for an EPA rated 81 miles of range. The B-Class ED uses a 36 kW battery for an EPA rated 87 miles of range. It depends on what you want, I wanted a Tesla but could't afford it, this Mercedes is perfect for me. If you are more of a purist the BMW i3 uses less energy, but you have to want to be seen in it! I prefer the fact that in the B-Class ED nobody looks twice at my car, unless you are a car enthusiast. I like to be discreet and not draw attention to what I drive. And the B-Class can actually seat four people without making them feel claustrophobic. The i3 is basically a 2-seater, (think Porsche 911). Or Smart Car. Also the B-Class can haul cargo very well. I'm 27 days into ownership and I am 100% satisfied with my choice. I looked at an i3 today again in the BMW showroom and could not see myself getting into that car any (every) day. I couldn't even do a test drive, I just wasn't feeling it.

 

[wtzouris]

MPGe is the official Efficiency Rating

Top Ten EPA-Rated Fuel Sippers of 2014:

2014 BMW i3 BEV 124 MPGe Combined
2014 Chevy Spark EV - 119 MPGe Combined
2014 Honda Fit EV - 118 MPGe Combined
2014 Fiat 500e - 116 MPGe Combined
2014 Nissan LEAF – 114 MPGe Combined
2014 Smart Fortwo ED Cabriolet - 107 MPGe Combined
2014 Smart Fortwo ED Coupe - 107 MPGe Combined
2014 Ford Focus Electric – 104 MPGe Combined
2014 Tesla Model S 60-kWh – 95 MPGe Combined
2014 Tesla Model S 85-kWh – 89 MPGe Combined

So, the BMW i3 BEV is the efficiency champ, but what really matters is what’s its range rating? Well, it’s not bad given its 22 kWh (18.8 kWh useable) battery pack: 81 miles of electric range

At the bottom:
2014 Mercedes-Benz B-Class Electric Car: 87 Miles Range, 84 MPGe

 

[JeffRay]

Would someone post the range rankings for pure electrics?

 

[GlennD]

In the week I have had my car I am averaging 2.8 MPKW according to the display. Certainly less than my old Leaf SL but I think the trade off is worth it. So far I love my B class!

 

[JeffRay]

10. Smart ForTwo Coupe: 68 miles ($25,000)

9. Focus Electric: 76 miles ($29,170)

8. BMW i3: 81 miles ($41,350)

7. Chevy Spark EV: 82 miles ($26,685)

6. Volkswagen e-Golf: 83 miles ($35,445)

5. Nissan Leaf: 84 miles ($29,010)

4. Mercedes B-Class Electric Drive: 85 miles ($41,450)

3. Fiat 500e: 87 miles ($32,300)

2. RAV4 EV: 103 miles ($49,800)

1. Tesla Model S 85 kWh: 265 miles ($79,900)


Read more: http://wallstcheatsheet.com/automobiles/top-10-electric-vehicles-with-the-longest-driving-range.html/?a=viewall#ixzz3Q3YyRA9b

 

[rdavis0521]

Various other authors here have asserted that the miles/kWh readings shown in the B dash are wall-to-wheels, not battery-to-wheels. Because of that it's assumed that you can factor that by approximately 20% higher. So, your 2.8 should actually be around 3.3 miles/kWh. I am not sure if other vehicles provide W-W or B-W info. It would make most sense to me that the car usage would be B-W, but for whatever reason, Mercedes chose to include the charging loss from the wall.

I average around 2.9 on my car. I've seen as high as 3.6, but generally on freeway I see about 3.2 most of the time.

With those values, I have ranges that should be in excess of 90 miles, but i've never taken it down to zero.

Ray

 

[sendler2112]

I think that much of the difference in efficiency comes from the fact that Mercedes decided to design the in dash read out to reflect all of the power that is used from the wall to the wheels whereas some other manufactures are stating an optimistic value of only the portion of energy that leaves the battery.

 

[wtzouris]

30 degree day today. I went for a standard charge. 26 miles driven. 67% SOC remaining.
The mpkWh average from Start and Reset is 2.6. So if you multiply that by 28 kW useable on a standard charge you get 72 miles, and if you just multiply my 26 miles x3 ( I used up 1/3 battery in percentage) you get 78 miles of range, pretty close!

Now it has been suggested that that number should be multiplied by 1.2 because Mercedes calculated the mpkWh meter as WTW (Wall to Wheels) to account for charger efficiency. So 3.0 mpkWh is really 3.6 mpkWh, etc. etc..

 

[wtzouris]

25 degrees on the way home. 26 miles driven on standard charge, this time using the heater, and regular E mode not E+. And headlights. 2.0 mpkWh average, 41% SOC used (59% remaining ), so I estimate 65 miles of range. The mpkWh kept going up, the car was driven for 40 minutes, and I did not pre-condition. I think the efficiency really improves as the car and battery warms up.

 

[SmartElectric]

The difference in efficiency is not particularly relevant to the pocketbook when comparing the current crop of electric cars.

Lets see how much it costs for 100km using $0.20/kWh for the electricity rate (including taxes and charger inefficiencies), that means it costs.

My Smart ED when driven the way I do, namely, mashing the pedal to the floor at every opportunity and running cabin and seat heaters on max for a short 10 minute drive in -15C gets 35kWh/100km. Cost is $7/100km.
Compare that to my summer average of 20kWh/100km. Cost is $4/100km.
Compare that to other owners who average 15kWh/100km in the summer. Cost is $3/100km.

That's three very different efficiencies, but the cost difference is practically nothing.
Given you are comparing cars costing tens of thousands of dollars, it would take a long time for a difference in efficiency to matter in the grand scheme of things.

Oh, and I "fill up" on 100% renewable power, so have no care in the world for efficiency when I drive.
Long live the Smart ED at full throttle!

 

[sendler2112]

That is a difference of more than twice as much. Very big difference.
.
I drive 120km per day. It adds up.

 

[mikegerard]

25 degrees on the way home. 26 miles driven on standard charge, this time using the heater, and regular E mode not E+. And headlights. 2.0 mpkWh average, 41% SOC used (59% remaining ), so I estimate 65 miles of range. The mpkWh kept going up, the car was driven for 40 minutes, and I did not pre-condition. I think the efficiency really improves as the car and battery warms up.

Efficiency is very dependent on battery temp. And as the battery warms up so does the cabin. So the battery can move more electrons and the battery and cabin heater can start cycling on and off.

 

[bcurious]

The difference in efficiency is not particularly relevant to the pocketbook when comparing the current crop of electric cars.

Lets see how much it costs for 100km using $0.20/kWh for the electricity rate (including taxes and charger inefficiencies), that means it costs.

My Smart ED when driven the way I do, namely, mashing the pedal to the floor at every opportunity and running cabin and seat heaters on max for a short 10 minute drive in -15C gets 35kWh/100km. Cost is $7/100km.
Compare that to my summer average of 20kWh/100km. Cost is $4/100km.
Compare that to other owners who average 15kWh/100km in the summer. Cost is $3/100km.

That's three very different efficiencies, but the cost difference is practically nothing.
Given you are comparing cars costing tens of thousands of dollars, it would take a long time for a difference in efficiency to matter in the grand scheme of things.

Oh, and I "fill up" on 100% renewable power, so have no care in the world for efficiency when I drive.
Long live the Smart ED at full throttle!

I like the driving enthusiasm expressed here.
The math may not be as clear.
If you leased the Smart ED for the advertised $12,500-ish price, it's in the ballpark of $12/day, $16/day if counting only 5 days of use per week.
A 100km commute for $7 versus $3 isn't terribly expensive, especially in comparison to some petroleum vehicles and potential non-financial measures, but isn't nothing, either.

 

[TonyWilliams]

Range at 65mph (100km ground speed) on dry, hard surface level road with no wind or cabin climate control with new condition battery at 70F, battery capacity is "useable" amount, not advertised amount. Ranges are at maximum available charge and EPA rating is the maximum published.

GM / Chevrolet
2014 Spark EV - 5 miles per kWh (200 wattHours per mile) * 19kWh = 95miles / EPA 82

2015 Spark EV - 5 miles per kWh (200 wattHours per mile) * 18kWh = 89 miles / EPA 82


BMW
i3 - 4.7 miles per kWh (213 wattHours per mile) * 18.8kWh = 89 miles (the "REx" version has less electric range)


VW
eGolf - 4.1 miles per kWh (244 wattHours per mile) * 24kWh = 100 miles


Nissan
LEAF - 4 miles per kWh (250 wattHours per mile) * 21.3kWh = 85.2 miles / EPA 84


Mercedes
B-Class ED - 3.6*** miles per kWh (278 wattHours per mile) * 31.5kWh = 113 miles / EPA 104
*** Mercedes consumption meter is calibrated so that 3.6 miles per kWh will show 3.0 on the dash. The correction factor is 83.7%, or 1.2


Toyota (NO LONGER AVAILABLE NEW)
Rav4 EV - 3.4 miles per kWh (295 wattHours per mile) * 41.8kWh = 142 miles / EPA 113

 

[sendler2112]

Have you personally observed someone getting 200Whr/ mile in a SparkEV? That seems unrealistically high. Where does that number come from?

 

[GRA]

Have you personally observed someone getting 200Whr/ mile in a SparkEV? That seems unrealistically high. Where does that number come from?

http://insideevs.com/real-world-test-shows-chevy-spark-ev-has-substainally-more-range-than-nissan-leaf-62-mph-wvideo/

Note the person who conducted the test