Ride in the Mercedes CLA EQ: Drive on efficiently

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It took a while: electric cars with a voltage level of 800 volts have been available for years, but so far only Porsche and Audi have been able to deliver this from German manufacturers. This year, BMW and Mercedes are finally following suit with the "New Class". The CLA, which was shown as a study at the IAA in Munich a year and a half ago, is of course just an offshoot on a basis on which Mercedes will build a series of models. In addition to the saloon and an estate, which may no longer be called that, SUVS will also use this platform. We were able to take the next-generation CLA for a spin shortly before the official launch.

800 volts: why is that important?

Doubling the voltage to 800 volts opens up the opportunity for significantly higher charging capacities than before. Although the increase in voltage alone is no guarantee of this, it does provide a kind of template. The power can be increased without increasing the current. As many charging stations only supply 500 A, a 400-volt system stops at 200 kW. With 800 volts, 350 kW and more are possible. Whether the battery and its peripherals in the respective car can cope with this – and under what conditions – is another matter. For the foreseeable future, a manufacturer who wants to be among the leaders will have to deliver significantly more than 250 kW, and not just in the laboratory within a small SoC window.

Mercedes promises up to 320 kW charging power on this basis. This would currently put the brand at the forefront. Ideally, ten minutes should be enough to recharge for 300 km. Initially, 58 and 85 kWh are planned for the CLA. The structure is different: the larger battery has a silicon oxide anode, the other is fitted with a lithium iron phosphate cathode. The hardcase cells are combined in four large modules and are repairable.

Efficiency should bring more range

With the Vision EQXX study, Mercedes already indicated a few years ago that larger batteries are not always the only solution in the search for more range. Increasing efficiency is an important component. All cars on this basis are therefore equipped with a multi-source heat pump, which uses various sources to heat the interior as quickly as possible and should only require a third of the energy of a conventional electric auxiliary heater. The elimination of water cooling for the heat pump also reduces the weight.

Two synchronous machines

Mercedes' decision to use two synchronous machines is unusual. Many manufacturers use an asynchronous motor on the secondary axis, i.e. the one that does not always contribute to the drive, which does not generate any drag losses when running without current. Mercedes argues that a synchronous motor is more efficient in operation and offers higher recuperation performance. In order to avoid drag losses, the electric motor is disconnected from the propulsion system with an electrically activated claw clutch when required. This solution is more complex than the variant with an ASM, but should ultimately benefit fuel consumption. This also applies to the two-speed gearbox on the rear axle, which Mercedes hopes will further reduce power consumption.

The provisional top-of-the-range version of the CLA offers 200 kW at the rear axle and 80 kW at the front axle. The system output is 260 kW. Versions with less power will follow, AMG will add more at the top. How much is a well-kept secret, but it is becoming increasingly difficult to stand out from the competition in this respect. Especially as the tangible added value for the customer is hardly noticeable when performance increases beyond a certain level. Many electric cars already accelerate brute force today, and when things get a little faster, you approach a limit at which "more" is not perceived as "better".

Only two driving modes left

Despite the snow-covered road, the first test lap is quick – not least thanks to the all-wheel drive. There are only two driving modes: Comfort and Sport, and that's it. The steering is precise and the control systems give the rear more freedom in the Sport program. But never in such a way that it appears nervous. On the contrary: the ESP regulates sensitively. Even if the stability program is largely deactivated (it cannot be switched off completely), the CLA remains very predictable and is easy to recover.

Recuperation is also set using the automatic lever on the steering wheel: in addition to a strong energy recuperation mode, there is also a milder mode, an automatic mode and a mode that enables coasting. The braking behavior is also interesting. The Brake Control System (BCS) is used in both the BEV and mild hybrid versions and is available for all drive and chassis variants of the CLA series. It uses all actuators in the car, has 100 functions and supports the driver in almost all situations, explains technician Philipp Neuwirth. The highlight is that the brake pedal is decoupled, the braking feel always comes from the BCS unit and should therefore always be identical. We can give the prototype a good report card. The pedal travel to the pressure point and the feel remain the same, both with a full stamp and progressive deceleration when the vehicle is fully loaded.

Presentation: very soon

The official launch of the CLA is due to take place in the coming weeks. The saloon will be followed by the Shooting Brake, which will serve as a replacement for the estate. Mercedes will quickly follow up with several SUVs, which will then replace the current EQA and EQB models. With 70.5 kWh (net) energy content, they do not look bad at all at first glance. However, the maximum DC charging power of 100 kW indicates what has happened in electromobility since their launch in 2021. Even then, however, Mercedes was by no means at the forefront in this respect. This is likely to change with the MMA platform of the new CLA.

(olb)