Mercedes-Benz B-Class Electric Drive – EPA Rated 87 Miles Of Range, 84 MPGe

5 months ago by Eric Loveday 43

B-Class Electric Drive

B-Class Electric Drive

EPA Rating For Tesla Model S 60 kWh

EPA Rating For Tesla Model S 60 kWh

Electric vehicles with Tesla components (battery, motor, etc.) are not known for efficiency.

That holds true with the Tesla-powered Mercedes-Benz B-Class Electric Drive.

The Tesla Model S fares rather well in terms of efficiency due to it being the most aerodynamic plug-in vehicle available today, but the level of efficiency for Tesla-powered electric vehicles falls off dramatically when those components are fitted to less aerodynamic offerings.

Case in point: The Mercedes-Benz B-Class Electric Drive just received it MPGe ratings:

  • 85 MPGe City
  • 83 MPGe Highway
  • 84 MPGe Combined

Those numbers are really poor when compared to the most efficient BEV in the world:

EPA Comparison - B-Class Electric Drive And BMW I3 BEV

EPA Comparison – B-Class Electric Drive And BMW i3 BEV

But when we toss the other Tesla-powered BEV into the mix, the B-Class Electric Drive clearly excels against the less aerodynamic and heavier Toyota RAV4 EV:

EPA Ratings: B-Class ED, BMW i3 BEV, Toyota RAV4 EV

EPA Ratings: B-Class ED, BMW i3 BEV, Toyota RAV4 EV

We’d like to point out one aspect that’s been wholly omitted by many when reporting on the B-Class Electric Drive MPGe figures.  The EPA doesn’t test the B-Class ED with the optional range package (range mode button, which allows for 100% charging).  So, for testing purposes, the B-Class ED is burdened with several kWh of extra capacity (28 kWh usable with standard charge from 36 kWh battery pack) that adds weight to the vehicle, while not contributing one bit to its range rating of 87 miles.

This added weight certainly hurts its MPGe figures, but it seems M-B made the right choice by not focusing on getting the best EPA numbers, but rather pleasing buyers by offering the additional 17 miles of range (104 miles of total range when 100% charging is selected) we all desire.  M-B could have just opted for a smaller battery pack (say 32 kWh) to improve its MPGe figures, but doing so would have limited range to 87 miles, well below the 104 available when the range packaged is opted for.

Props go to Mercedes-Benz for ignoring the various rules and regulations that BMW got so caught up in.  What Mercedes-Benz did was to provide us with the vehicle we want, not the EV that seeks to steal headlines by being the most efficient electric in the world.  It’s not often that an automaker overlooks the chance to gain bragging rights in favor of delivering a better overall product to consumers, but M-B clearly took that route here.

First US deliveries of the B-Class Electric Drive are expected to occur any day now, with tipster Ray Davis expected to be one of the first in the US to receive his much-anticipated electric Mercedes-Benz.

Hat tip to soon-to-be Mercedes-Benz B-Class Electric Drive owner Ray Davis!!!

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44 responses to "Mercedes-Benz B-Class Electric Drive – EPA Rated 87 Miles Of Range, 84 MPGe"

  1. kdawg says:

    When “100% charging” is selected. How much actual % of the battery capacity is that?

    1. Eric Loveday says:

      I believe its 33.5 kWh.

      1. Eric Loveday says:

        ~ 93 %

  2. John says:

    Maybe I don’t know how they test for efficiency (MPGe), but wouldn’t extra weight affect the rating regardless of whether or not it was charged?

    I can see it affecting the range rating of course, but efficiency?

    1. Mint says:

      Yes, weight will affect both range and efficiency.

      But I think it’s unfair to compare the B-class with the i3, as the former is quite a bit roomier. Between the larger vehicle size, +14kWh larger battery (~100 kg), and lack of CFRP, it weighs ~50% more.

      Still, I’d rather have a REx than longer range.

  3. anonymous says:

    this MPGe measurement is the most stupid thing they created as we are talking about BEV’s that don;t use a single drop of fuel. It doesn’t make sense for me even some will advocate that a comparison measurement is necessary. For me we should compare the efficiency of electric vehicles in terms of how much electricity they use – we should compare with houses consumptions figures and not with fossil fuel powered machines. The way the information is presented is a disservice for society…

    1. yiiikes says:

      + 1
      There are NO gallons in a BEV, get with it people. The one thing anybody cares about is how much does it cost to drive each vehicle. MPGe does not tell that story all.
      http://insideevs.com/op-ed-time-new-metric/

    2. mustang_sallad says:

      I agree it’s annoying to me as an EV enthusiast, but in terms of society as a whole, I think 88 MPGe catches the general public’s attention a lot more than some nerdy kWh/100mile rating. It gets the point across to the general public without any knowledge of what a kWh is that an electric car will use a lot less energy and will cost a lot less to run.

      1. Mint says:

        On top of that, cost coincidentally matches fairly closely, as a gallon equivalent is 33.7kWh of electricity, which costs about $3.50.

        So 90 MPGe will need roughly 1/3rd the cost of fuel as 30 MPG.

        For the average consumer, it’s a good system. Educated people can read the fine print or calculate other units by themselves.

        1. SeattleTeslaGuy says:

          That, sir, is the best explanation I’ve heard about MPGe. It still is a bit difficult explanation due to a fairly wide range of electricity rates.

          Personally, I wish they had gone to cost per mile or similar.

        2. ELROY says:

          Absolutely, it is equivalent based, and is easy to make comparisons. No need to get into semantics about how a electric car doesn’t use gallons. Its the equivalent. Just like saying the electric car doesnt’ run on dollars directly, but we would still like to know how many dollars it costs to run.

  4. pjwood says:

    A 104 mile BEV is different from a BEV that has to be deliberately charge extended, to offer 104. The point is many don’t know beforehand, that they will need the extra miles “in a pinch”, and defaulting to it is harmful.

    Tesla’s EPA rating method equates to the MB’s 104, not the 87, based on a similar ~90-93% charge. But in that case few routinely need 265 miles. They don’t “range charge” every night.

    So, in the end, unless the electric windshield significantly shaves heat use, this car doesn’t make sub-freezing sense for those who absolutely must occasionally get ~70 miles. Normally need ~55, but can’t predict that cold day of 70, or slow slushy traffic jam? Don’t get this car.

    1. kdawg says:

      What is the range of a Model S when it is not range charged? Do you know what % of the battery capacity is charged? 90%?

      1. pjwood says:

        Yes, 90%, I believe. I’ll let the Tesla afficianados post miles and %, @normal charge, for the 85kwh. I think its ~210-230, or so.

        The other issue is will this be like the 8amp default on the newer Volts, where the “Range button” can only be pressed when the car is put to bed, and can’t be defaulted, or selected over handheld or internet.

        I’ve had thoughts that, if you range charge the MB right before using it, and only defaulted during, say, sub-freezing weeks/months, maybe things would work out alright. I just don’t expect this could be configured thoughtlessly, by default.

      2. SeattleTeslaGuy says:

        My P85 in “normal charge” mode has a target SOC of 85% and lists 233 miles.

      3. Tesla Model S 85 kWk “daily” charge range is 230 mi, 86.7% of capacity. 73.77 kWh

    2. Alonso Perez says:

      With an EV, slow traffic makes range approach infinity. Well, maybe not with the heater on, but still, slow speed greatly favors EVs.

      The problem with the B class is simple. It’s a regular steel car. It just weighs a lot more. You can think of that as a problem or an advantage. Body repair will be conventional and the car uses normal tires. You do give up efficiency but you are so far ahead by being in an EV that it may not be too important.

      My biggest issue with the B class is its lack of quick charging, not efficiency.

      1. pjwood says:

        -The Volt, in EV mode, is the same as the MB on these two fronts, normal ~215 tires and 3,800lbs.
        -Weight is a virtue, if you want touring car characteristics.
        -The BMW going to 155mm width tires was as crazy as the ELR going to 245′s.

        Mainly, I don’t think 3,800lbs is some great sin. Sports cars, like the M3, and S5 porked out to this weight a long time ago. There are lots of cars 3,600-3,800lbs. It just tests a BEV’s capabilities, to put a battery in a “normal” car. -One that handles better with the weight lower, and between the front and rear axles.

  5. David Murray says:

    I still can’t believe the styling on this car. And people say the Leaf is ugly… geez.

    1. kdawg says:

      It just seems dated to me. It’s an EV for Pete’s sake. Give it some contemporary styling.

      Of course I do not claim to know MB’s market.

      1. yiiikes says:

        Very 2011 – that is why Audi and BMW are leaving MBz in the dust in sales.

  6. Mint says:

    I think this is proof that Tesla has work to do on its regenerative braking.

    The Model S had almost no difference between city and highway MPGe, unlike almost every other EV. One partial explanation was that it was very heavy but very aerodynamic, so highway MPGe wasn’t bad but city MPGe took a hit.

    The B-Class ED is less aerodynamic than the Model S and weighs less, but we still have little difference between city and highway MPGe.

    To me, that means poor regenerative efficiency is the culprit. I know it’s requires more sophisticated control to get regen from an induction motor than a permanent magnet motor, but I still think Tesla can do better.

    1. pjwood says:

      4,800lbs of inertia does a number on Tesla city efficiency. Otherwise, the B-class / I3 contrast of 36kwh / 22kwh, yet 87mi / 81mi, is simply glaring, no matter what we point to.

      I’d also land on keeping one’s eyes on the range prize, and would horse race the MB as lasting longer.

      1. JakeY says:

        “B-class / I3 contrast of 36kwh / 22kwh, yet 87mi / 81mi, is simply glaring”
        If you are going to use 87 mi, the B-class number you should use is 28kWh. If you are using the 36kWh (not all of which is usable even with the “extended range” package) the number is 104mi vs 81 mi.

        1. FFY says:

          If you are going to use the usable capacity, you have to do it for both cars. The i3 uses 18.8 of the total 22 kWh.

          1. JakeY says:

            Okay, then use: 28/18.8 vs 87/81 or 36/22 vs 104/81.

            1. FFY says:

              I don’t think that claiming 104 miles for the B-Class makes sense, because you cannot use it regularly without damaging the battery.

              1. JakeY says:

                Not true at all. That 87mi vs 104mi is simply the same “standard” vs “range” mode that all Tesla based vehicles have. It’s not going to “damage” the batteries. And supposedly usable in 104mi mode is 33.5 out of 36kWh total, so there’s still a healthy 93% DOD window.

                The automakers understandably want to discourage use of higher SOCs, but as long as you don’t keep it at high SOCs for long periods of time (which is a battery life killer), even using the high SOC daily is not going to impact battery longevity much (Tesla owners do this by setting the charge timer to finish at around the time when they leave).

                1. FFY says:

                  Well, if that were so harmless, BMW could easily “extend” the range of the i3 with a simple software modification as well. But I think there are good reasons for battery overprovisioning. Long battery life is more important than squeezing a few extra miles out of the battery for “bragging rights” (as the article put it).

                  1. JakeY says:

                    @FFY
                    Yes, BMW can do an extension too, but given it’s already using 18.8kWh/22kWh, the most they can get is 102 miles (using 100%). At the same 93% DOD as the B-Class it’ll be 95 miles. So the B-Class will still be clearly ahead in range.

            2. Mint says:

              You guys are making things too complicated. MPGe tells you how much energy is used per mile.

              On the highway, the i3 gets 111 MPGe and the B-class gets 83 MPGe. We can blame a combination of 50% higher weight for maybe 15% higher MPGe, and then tires, and CdA (primarily due to being bigger) for most of the rest.

              In the City, the i3 gets 137 MPGe, or 23% more miles per kWh. Most EVs see the similar gains, and it’s in stark contrast to ICE cars with have lower city MPG. HEVs do much better in the city, but generally still only match city and highway MPG. EVs get even bigger boosts in the city, and the only realistic explanation for that is more efficient regenerative braking (large battery means 1C or 2C charging during during EPA test regen instead of the >10C in regular hybrids).

              But the Model S and B-class ED are outliers. They don’t get much higher city MPG. Sub-optimal regen is likely the culprit.

        2. pjwood says:

          Not sure 28/22 vs. 87/81 is much less glaring (27% more batt., 7% more range), especially if we’re going to compare the apple and orange of MB-available capacity vs. BMW total capacity. The Bimmer actually uses only 18.8kwh (85%).

          I’d far and away prefer the MB, regardless, but I think the under-utilization of capacity is a shame. We’re posting 85%, 87.6%, 90% and 93%, so far in this entire thread as DOD rates. The next Chevy Spark EV looks to be 91%, after its 2kwh diet (to 19). Then, there is the B-class BEV, down at 77%.

          I’ve forgotten to plug in the PHEV maybe 3 times, in ~2 years. It has meant a little more gas, but forget to range charge the MB on any day you need those miles, and you are stuck. That’s why I hope, for Mercedes sake, the range extender is always-on, or always-off, at user discretion. If I can forget, believe me, so can my wife.

          1. JakeY says:

            See my post above. My main point is that the 87 miles for the Mercedes is not the highest usable level it can go with the current battery pack. In case it’s not clear, the 104mi refers to the “extended range” package, which is the same mode tweak as the Model S / RAV4 / Leaf (etc) has, except Mercedes is charging money for it.

            Assuming 33.5kWh is used for that mode, DOD is 93% which isn’t too bad.

    2. JakeY says:

      Well it doesn’t apply to ALL Tesla based EVs. The Smart ed had 94 city and 79 highway.
      http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=31065

    3. JakeY says:

      I think it may also depend on how the default regen configurations are set. The i3 is configured out of the box with very aggressive regen that can regen to a stop. This may not be the case with the B-Class.

      In terms of max power, the i3 regen is 50kW, the Model S is 60kW, so I don’t think it’s an “efficiency” issue. It’s just the profiles are different (for one, the Tesla is less aggressive at low speeds and doesn’t regen to a stop), likely for driver experience reasons.

  7. FFY says:

    There is a reason why the rated range of the B-Class is 87 miles rather than 104: Regular use of the full capacity will damage the battery. MB itself states that it should not be used too often.

    The reason that the B-Class is so inefficient is simple: It is just a very heavy car.

    Likewise, the claim that “The Tesla Model S fares rather well in terms of efficiency” is questionable. 95MPGe is not efficient for an EV.

    1. Alonso Perez says:

      95MPGe is plenty efficient for an EV the size and capability of the Model S.

      Full capacity use doesn’t “damage” the battery. It’s more accurate to think that it ages it quicker, just like driving at higher speed increases engine wear in ICE cars.

      The compromise of having it for occasional use is a perfectly sensible engineering solution.

  8. Peder says:

    I would offer that the bulky weight of the Mercedes as compared to the BMW i3, affect more than just range and efficiency.

    Things that drivers also care about such as speed, quickness, nimbleness, handling, and braking are all going to in favor of the BMW due primarily to weight.

  9. Steve Strange says:

    If Nissan delivers a 36kWh LEAF option in MY2016, it looks like it could easily beat the MB’s range. That would remove the primary reason I’m looking at the MB.

  10. Tom says:

    I don’t know about the specs on the B class, but I have a Leaf and a RAV4. The RAV4 is definitely less energy efficient for a variety of reasons, but there is no way I would pick the Leaf drivetrain over the RAV4. The Leaf struggles at high speeds and the AC puts a heavy load on the car, it’s not common to get down to 2.8-3.0 kw/h on a hot summer day. Meanwhile the change in driving style doesn’t seem to hurt the RAV4 as badly. Thi

  11. GRA says:

    The biggest advatnage I see for the B-cvlass is that it’s using a much smaller % of it’s total capacity to achieve its 87 mile EPA range, which along with a full active TMS should make the battery last far longer than BEVs that use a higher % of their total capacity to achieve their EPA range. For a commute car, long-term durability of the battery is more critical than maximum range.

    And when you need it, having the ability to go an extra 15-17 miles is quite handy. Bottom line, the B-Class is currently the lowest-priced BEV that gives you a true 100+ miles of EPA-cycle range, even if they don’t put it on the Monroney. The Leaf would be a 66 mile EPA car under the same circumstances.

  12. I wonder how the various regen options affect the Wh/mile on the B-Class? I hope we get in-depth reviews that deal with this.

  13. The B-Class needs to go on a high-fiber diet. I hear BMW tried it on the i3 and lost 1,200 lbs.

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