How much is a Mercedes Benz battery?

This blog will answer the following questions: How much is a Mercedes Benz battery? What are the different batteries found in Mercedes Benz cars? How to replace a Mercedes Benz battery? 

How much is a Mercedes Benz battery?

A Mercedes Benz battery can cost from 200 to 300 USD depending on the battery capacity. The auxiliary battery will cost between 30 -120 USD. The most commonly used main battery in Mercedes Benz is 80Ah 800 A. All the models use the main battery for starting the engine and an auxiliary battery for emergency parking and supporting the main battery.

Mercedes Benz used a two-battery concept in the models like the S class and the SL manufactured between 2006 -2012. One battery was fully dedicated to the task of starting the engine while a larger capacity main battery was used for powering the vehicle.

This two-battery concept allowed for the uninterrupted operation of interior functions even when the vehicle was starting. The voltage drop due to the starter motor is only present on the starter battery; the main battery remains unaffected by the current consumption of the starter motor.

The downside of the two-battery concept was an increase in weight and battery cost. The starter battery cost was more than the cost of the additional battery found in the current generation model.

Mercedes Benz completely abandoned the two-battery concept from 2015 onwards. All the manufactured cars used the single battery concept. It consists of a single main battery with a voltage sag limiter device. 

The Voltage sag or dip limiter limits the voltage drop at the main battery when the starter motor is engaged. This resulted in lowering the costs of battery replacement in Mercedes Benz cars. A small capacitor or an 8 Ah battery is used for the emergency P gear.

Ideally, Mercedes Benz batteries last for 3-4 years. The battery life depends on the state of charge and the overall operating temperature. If the vehicle is under the standard warranty period, the main battery and additional battery can be claimed if there is any malfunction.

What are the different batteries found in Mercedes-Benz cars? 

The different batteries found in Mercedes Benz cars are explained below:

12 Volts batteries.

12 Volt batteries are present in all the Mercedes Benz cars. The main battery and the auxiliary battery are 12 V, the number of cells can vary depending on the battery capacities. All the onboard control units need 11.5 to 14.5 V to operate.

The 12 V batteries are charged by an alternator and the charging voltage is 14.5-15.0 V. the battery management control unit monitors the state of charge and reduces the charging voltage when the battery is charged to 80%.

The 12 V battery is installed in the engine compartment and in a few models like the GLE/GLS and the S-class it is installed in the passenger compartment. There is only one battery management system and it uses a battery disconnect switch if the onboard electrical voltage goes below 11 V when the vehicle is locked.

All the 12 volts batteries used in Mercedes Benz cars have absorbent gel matt instead of liquid. There are valves to regulate the lead acid present in the mat. The AGM battery can maintain a steady power supply and the outside temperature has less effect compared to the flooded batteries.

48 volts battery

The 48 V battery is present in the Mercedes Benz cars with mild hybrid technology. The 48 volts battery is a lithium-ion battery with a built-in battery management system. There is also a coolant circuit to keep a constant temperature in the lithium-ion cells.

This 48 volts system is different from two 12 V batteries connected in parallel. The 48 volts is a completely independent system in Mercedes Benz. It is used to power an electric motor that supports the internal combustion engine by producing an additional 21 bhp.

The motor can be belt driven by the crankshaft or it is sandwiched between the engine and the transmission. The same electric motor is used to generate the power and charge the 48 volts battery.

A DC-to-DC converter is used to charge the onboard 12 volts electrical battery. It is present on the 48 volts battery. Based on the model, the 48 volts battery is present in the engine compartment or under the third-row seat.

There are also some components like an electric air-conditioning compressor and a supercharger that directly run on the power supply from the 48 volts battery. There is no need to manually disconnect the 48 volts battery, disconnecting the onboard 12 volts battery will disable the 48 volts system.

400V battery pack

This is present in plug-in hybrid and fully electric cars. Mercedes Benz has a dedicated sub-brand called EQ. The battery pack consists of two to three battery management control units. This is a high-voltage electrical system and it requires special knowledge to work on these battery packs.

There are master circuit breakers present within the battery pack housing and it is connected to coolant as well as refrigerant circuit. When the battery is charged the temperature in the lithium-ion cells rises, if not cooled it will damage the cells and reduce the life of the battery pack.

There is a 12 V interlock circuit in the high-voltage electrical network. However, working on the high-voltage battery without properly disconnecting the system can result in injury. 

The positive and negative of the 400 V circuit originates within the battery pack and return to it. It has a galvanic separation from the vehicle ground.

How to replace a Mercedes Benz battery?

The procedure to replace a Mercedes Benz battery is given below:

• Turn off the vehicle ignition and store the key 2m away from the vehicle.
• Remove the engine compartment panel to gain access to the battery. 
• Disconnect the negative terminal first and connect it last after replacing the battery.
• Remove the screw for the battery bracket and carefully remove the old battery.
• Install the new battery and properly secure the battery bracket.
• The battery terminals must be correctly installed and apply 16 Nm torque.

Visually inspect the battery, there should be no cracks on the battery housing. Connect the vent pipe after installing the new battery. There is no need to connect a battery charger to keep the memory of the control unit alive.

After replacing the battery, drive the vehicle for a few meters. The clock will be set as soon as the GPS signal is acquired, other driver settings are not affected after disconnecting the battery.

Conclusion

This blog answered the question of how much is the Mercedes Benz battery and explained the various types of batteries found in Mercedes Benz cars. Regularly using the vehicle and not keeping the ignition ON for too long will help to keep the battery in good condition.