Is Mercedes-Benz Pulling a Tesla By Offering Optional Bigger Battery Pack in B-Class Electric Drive?


It’s long been established that Daimler is using Tesla provided drivetrains and battery packs for the upcoming B-Class Electric Drive. However, I’m beginning to believe the electric B-Class may be borrowing one move from the Tesla playbook: An optional, larger battery pack.

Hey, What Is Happening In Here?

Hey, What Is Happening In Here?

Back in November, I had a conversation with Heiko Schmidt, product manager for Mercedes Benz USA, at the LA Auto Show regarding the B-Class electric drive. While Schmidt didn’t offer any indication of an optional, larger battery pack, he did however tell me that Daimler understands the psychological impact of seeing a triple-digit number on the Monroney window sticker and stated “Our clear target is to have that in the three-digit range.”

Mercedes has announced the battery pack will be 28 kWh. That is the total size of the pack, so figure the maximum usable amount to be around 25 kWh.

On the NEDC range test, the B-Class achieved a 200 km range, however before anyone gets excited, the NEDC test is not very strenuous and isn’t really an indication of how the vehicle will perform in real world driving conditions. As comparisons, the 2013 Nissan LEAF achieved a 200 km range and the BMW i3 did 190 km. You cannot simply do a direct conversion from NEDC to EPA to get what the range will be because the tests are very different, but since the LEAF then achieved an 84 mile range on the EPA 5-cycle test, I would expect the B-Class to be similar.  Well short of 100 miles, nonetheless.

Mercedes B-Class

Mercedes B-Class

So, the B-Class will simply be another 80 to 90 mile EV, just like everybody else on the block without a Tesla badge, right? Well, perhaps not. During the past six months or so I have had the opportunity to talk to people close to the program and even some that have test driven the car (in industry speak, these individuals are referred to as insiders). I also have acquaintances that have talked with people close to the program both here in the US and in Germany and many of them have promised the B-Class Electric Drive will have a range well over 100 miles, actually closer to 120 in fact.

Panasonic 18650 High Capacity Lithium Batteries - Stuff More of These in the B-Class and Range Increases

Panasonic 18650 High Capacity Lithium Batteries – Stuff More of These in the B-Class and Range Increases

I don’t believe there is any way the B-Class will have more than a 90 mile EPA rating with a 28 kWh battery pack. While its aerodynamics are very good (0.26 drag coefficient), it’s still a very heavy car, tipping the scales at around 3,900 lbs. It will likely have better highway range than a LEAF for example, but not do as well when it comes to lower speed, city driving. So, if indeed the B-Class is to achieve the kind of range that I have heard from multiple sources, how can they do it?

The easiest way is to simply do what Tesla does and offer an optional, larger battery pack. A 40 kWh pack would likely give the B-Class enough juice to be EPA rated at about 120 miles per charge. They can offer this as a $5,000 option and call it the “Range Package”. In doing so, Mercedes would separate themselves from the pack and offer a degree of “premium” not found in any other pure EV outside of Tesla.

Yes, I do know the RAV 4 EV has this kind of range, but since it’s such a low production compliance EV that is limited to California, I personally don’t include it in the conversations with real production electric vehicles. That being said, the B-Class EV still may pan out to be a very similar compliance play, but for now I’m giving Daimler the benefit of the doubt as I have been assured it will be available all across the country, once production increases to the point where they can supply enough of them.

Initially, the B-Class will only be available in the CARB “Compliance States” of CA, CT, MD, OR, NJ, NY, RI and VT when it launches later this year, which is still much better than what Toyota is doing with the RAV4. However, I have been told that by 2015 the B-Class Electric Drive will indeed be available nationwide.

Will M-B Reveal a B-Class With More Range?  We Sure Hope So.

Will M-B Reveal a B-Class With More Range? We Sure Hope So.

What do you think? Am I crazy to suggest this? I do hope it’s true because we definitely need to start getting some electric options that begin to bridge the huge gap between the current crop of 80 mile EV’s and the 200+ mile cars being sold by Tesla.

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51 Comments on "Is Mercedes-Benz Pulling a Tesla By Offering Optional Bigger Battery Pack in B-Class Electric Drive?"

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Yeah Tom.

I don’t get why Mercedes would chinse on the battery so. At least have a big battery as an option.

Especially if Nissan is seriously looking to double the LEAF’s range, possibly with an optional battery upgrade.

If this is true, it is suspiciously similar to the i3 REx option price. I would pay $5k for 40 vs 28kWh.

40 kWh battery with NO quick charge? Have phun…

We’ve been driving all electric for over a year and a half and never needed quick charge. Where are you people going in these cars???

Same places as we go with our normal car, to relatives, friends, airports, vacations etc.

Anyway, it’s easy enough to put fast charging on an EV. It should be standard. Not optional, not unavaliable…standard.

Exactly Mikael. If not it is simply a city car. People don’t want that. Look at volt and leaf sales for proof.
The tesla supercharger network is the game changer. Makes interstate travel practical and very easy with an EV. Other car companies will never build out a network for their EV’s. As the EV is a very small part of their car production and not worth the added cost for them.

Exactly. Being able to get a 20-30 minute fast charge is great if you need to do some unplanned driving around town. It is also great for taking trips to nearby towns. Every EV should have DC fast charge standard. Not optional, and certainly not unavailable.


PS. Even if your driving patterns never require DC fast charging, the cost is minimal and it will help resale value.

Houston. I quick charge the Leaf 2 – 3 times a week.

I need to quick charge twice to make it to and from Hobby Airport (Southwest Airlines) from my house.

I drive a 40kwh battery car. It is fine for 99% of my driving and we have another electric car in the household that can go long distance when needed. 40kwh is not for long distance driving for the masses even with quick charging. The battery needs to be bigger for that. I have never and will likely never need quick charging for my 40 and my driving pattern is pretty normal.

Exactly. Tesla appears to insist that any batteries/motors it supplies not have DC fast charge capability. This handicaps any vehicle in comparison to Tesla. It is unacceptable and for that reason, I’m out.

Tesla execs have said not offering DC fast charging was Daimler’s choice, if I remember correctly.


Of course, it’s the respective vehicle manufacturer’s choice whether to install a DC quick charge port. Tesla has no special control over that. The Tesla Battery Management System is already extremely well equipped to handle 2C charge rates (that means that a 28kW Mercedes car could optimally take 56kW while charging). That rate can be handled by any ANY of the currently available DC charge standards around the world. Obviously, since Daimler is a member of the Frankenplug consortium, and there is close to zero of those charge stations in the world, it wouldn’t offer much utility today. Of course, Toyota could have put a CHAdeMO port on the Tesla powered Rav4 EV (they are a founding member of CHAdeMO), but chose not to, also. There are now over 3500 of those stations around the world, with 550 in the USA and 1000 in Europe, and a sizable chunk of those are in California where the Rav4 EV is sold. There is no incentive to make a car go over “100 miles” or have any premium charging options for CARB-ZEV compliance, and Daimler / Mercedes Benz must comply staring with the 2015 model year. Any discussion about EV’s that overlook… Read more »

Based on the background described in the article, I don’t arrive at the same conclusion. Offering multiple battery sizes requires considerable engineering planning and resources. I don’t see any evidence that this car has been infused with level of flexibility, in turn a function of planning and engineering resources. The fact that the manufacturer, long after having planned the car a few years ago, in retrospect regrets that it didn’t make a longer-range EV, is a different story.

I don’t see any evidence for a longer-range Mercedes pure EV, namely this B-Class, other than the fact that perhaps someone at Mercedes in retrospect regrets not having engineered such a version. I’m sure there are lots of people in the auto industry as a whole who regret that they back in 2008 or 2007 didn’t start to engineer the equivalent of a Tesla Model S.

They were all sure that Tesla would fail. Very sure.

I remember the snicker from a senior VW executive who completely dismissed Tesla as an entity. There were plenty of others, too.

I been thinking a lot how the b.class want to get 100+ miles. The b-class, as mentioned by severall german websites has 230 km max range, normal is 200 km but via an max range/charge button you get more. I suposse it uses the full 28 kwh if you like. 230 km necd translates to around 99 miles epa if you use leaf specs. Greetings, but i dont think it has more battery… 🙁

I been thinking a lot how the b.class want to get 100+ miles. The b-class, as mentioned by severall german websites has 230 km max range, normal is 200 km but via an max range/charge button you get more. I suposse it uses the full 28 kwh if you like. 230 km necd translates to around 99 miles epa if you use leaf specs. Greetings, but i dont think it has more battery… Sadly

When we talked to the two guys that were driving a B-class ED up on the East Coast back in August they were very shy to say anything about the battery capacity or the range of the car. If the B-Class ED gas conversion ends up with a significantly longer range than the purpose-built i3 it will be a real slap in the face for BMW.

Oh the wheels are turning at all the major auto brands, foreign and domestic. Lincoln definitely needs a shot in the arm, as it’s popularity is waning – how many luxe divisions can Ford dump? Cadillac has some life as long as gasoline prices are relatively low, and folks at all the brands are praying and lobbying for the Keystone Joke, er….pipeline. Maybe we can frack through Virginia and just do most states where lots of people just won’t notice the toxic water for awhile… Or maybe we can just look the other way whilst Putin and Medvedev have their way in Ukraine – to keep our O.P.E.C. pals satisfied a bit longer…. Mercedes has been sandbagging for so long, all it really does is try to set itself up JUST-IN-CASE this electric thing gets out of hand. So far, it’s toss a few bucks Tesla’s way and keep a foot in the door. This B Class is COMPLIANCE CAR 101. The “insiders” nabbed for this article amount to some guys testing a B-Classe Electric who stopped by the restaurant for a charge and some hearsay and third/fourth party talk. Not exactly “news” or even more than rumors, really. People… Read more »

The possibility of a larger battery is promising, but in order to “separate themselves from the pack” they need to have DC Fast Charge. I bought a RAV4 EV knowing it would probably never leave the SF Bay Area. I’m OK with that, but I’m not going to replace it until the next vehicle can take the family to Tahoe or LA. Any further than that, we would fly.

“separate themselves from the pack”…. L 🙂 L. I’m going to have to use that one!

Or – “set themselves apart from the pack”, or….. “Is LG the leader of the pack?!”…

etc. etc. etc. … OK, I’m done now…. 🙂

My name is TOMMY JOYCE! … I’ll be back at 11… just toss the tip
in the tip jar, thank you!

It intresting to see how a lot of people miss to see that the A-Class, B-Class, WV UP!, Golf Models had been developed with a so called “Sandwich-Boden” where a potential Battery can be placed…. check the trunk space – it is almost not compromized like it is the case with true conversion (e.g. Focus). As much as I like Nissan and their belief in EVs, their Leaf seems more of a conversion (Versa) trunk-wise…. The germans play it safe – wait for demand and act if needed – Battery supply might fire back on them one day….luckily Tesla is here move things forward 😉

The Germans very unsafely put their chips on diesel, because they do not understand” the US market.

The LEAF doesn’t share much w the Versa. Wheelbase is closer to the Sentra then Versa.
Folks don’t give Nissan enough credit.

Could it be possible that the 28kwh are the usable battery size and that it has 2-4kwh of additional unusable capacity like the Volt, which uses about 14 of it’s 16kwh? Could make sense in regard to the smaller cycle life of the Tesla cells, which would be of no concern in a large Tesla pack, but could drop the lifetime far under 8-10 years in a smaller pack if you cycle it close to 100% on regular bases. Also 22-23 usable kwh to 28kwh usable would be an improvement of about 23%, which would translate in an 84 to 104 range increase. Motor and regen could be more efficent (think highway) too.

Volt uses just 10, or 10.5, of its 16, or 16.5kwh

I have seen up to 52 miles using my V>olt’s measly 10.4 kWh allowed range. In good weather, of course.

If the 28kWh is usable, then the range at 250 watthours per mile (4 miles per kWh) is 112 miles.

That’s very believable, and achievable at about 100km / 62mph down the highway.

Yes, it may be possible to push the car to go that far, but that’s not what the window sticker or the EPA will say.
The EPA efficiency number on the RAV4 EV sticker is 44kWh/100mi. That is only 2.27mi/kWh. Your range chart says the RAV4 EV can do 3.4mi/kWh at steady 65mph. Also, most people can get 3mi/kWh in the RAV without even trying hard.

I maintain that the B-Class EV will have an EPA range of less than 90 miles on the window sticker.

Well since the wheelbase measurements are similar, how hard would it be for Tesla to use 40 kwh packs initially designed for the RAV4 in the B Class?

I could see MB over engineering the pack life by using software to only make 80% of the pack available and make the customer manually unlock the extra 4 kwh before each charge session.

Another tin hat theory is that this partnership with MB led to the cancellation of the 40 kwh Model S due to the size of the Mercedes order.

I’m still fascinated by the idea of a range-extender that’s a battery pack.

You can keep your usual buffer in the main pack, but for those long drives,
or times when an emergency calls – you tap into the extra pack for distance.
The additional pack could even be a different, faster-charging chemistry/
density with small buffer. Make the small pack swappable, and an option at
purchase. i3 could have a swappable battery instead of that ungainly 2 cylinder ICE
in that gap below the floor.

It sure makes more sense for me to change out the relatively small extender
pack ( or packs ) at smaller expense, than think about replacing the main
drive pack! No ICE range extender needed.

It seems like a simple thing to do by just swapping out existing cells. Upgrade from a UR18650E to a UR18650F upgrades each cell from 2150mAh to 2600 mAh for the same physical size

I think this is how Tesla does it.

Isn’t this Mercedes B class car literally a Tesla? (Built with a Tesla drivetrain.)

Like the Toyota Rav4 EV, the Mercedes B-Class ED shares the Model S drive train and Tesla designed battery pack (although, different cheaper cells are likely used).

Kia Soul EV is looking to be a 120 mile range car. Looking pretty good. If priced right, should outsell the Leaf if they sell it in 48-50 states.

Rather 90 mile. The Leaf is a 110 miles car according to NECD where the Soul will be a 120 miles car.

All LEAFs will drive about 80-ish miles of REAL WORLD range when at 62mph (100km) ground speed on a level, no wind, hard surface roadway with no heater and a new condition battery at 70F/20C or above temperature. The Kia Soul EV will be almost exactly the same. Here the LEAF official government rated range worldwide: 124 miles = 200km Japan “EPA” rating for 2011-2012 142 miles = 228km Japan “EPA” for 2013 109 miles = 175km UK / Euro 2011-2012 124 miles = 199km UK / Euro 2013-2014 73 miles = EPA-USA 2011-2012 75 miles = EPA-USA 2013 with 66 EPA miles for 80% and 84 EPA miles for 100% 84 miles = EPA-USA 2014 With the impending release of the 2013 LEAF, Nissan was suggesting to the press that a 2013 LEAF might go 250km (155 miles). Of course, the press just laps that up, as do EV advocates and EV consumers sometimes! The reality is that any model year LEAF will drive about 80-ish miles of range autonomy at 100km (62mph) on a dry, level, hard surface road with no wind or climate control, and without cabin climate control. The most important detail is the battery must… Read more »

What if they put the 40 pack in the car and reached an agreement to use the Tesla superchargers?

Now we’re talking.

That would be awesome, and a very compelling reason to buy the Mercedes.


Without DC fast charge capability, this car should be a no-sale for most people. This is especially true with a larger battery.

Oh, I don’t believe this. The problem is the market becomes extremely limited, which is fine for a converted car built for regulatory reasons in minimum quantity.

I’m sure M-B will be satisfied with compliance state sales less than 1,000 per year. They should be able to find that many customers.

The Leaf will have a real world range of 150 miles by fall 2014 to spring 2015. MB is a premium vehicle that can’t be sold successfully at double the price with less capability. The BMW doesn’t matter as it is a city car while the MB B-class is far more usable if it had a decent range. Right now we are targeted to replace our Camry Hybrid with the 150 mile Leaf unless MB announces something competitive.