[parabola]

I am close to purchasing new X5 xDrive 40i, but cannot seem to find any info on batteries in this car. I know it comes with the 48V mild hybrid system, and would like to know more about the 48V battery, longevity, cost to replace etc. I read somewhere that there are also two 12V batteries in the car, can anyone confirm?

[Auricom]

Originally Posted by parabola

I am close to purchasing new X5 xDrive 40i, but cannot seem to find any info on batteries in this car. I know it comes with the 48V mild hybrid system, and would like to know more about the 48V battery, longevity, cost to replace etc. I read somewhere that there are also two 12V batteries in the car, can anyone confirm?

Here's in the technical info on the G05 48V Mild Hybrid system. As far as longevity and cost to replace undetermined since the system is relatively new starting with MY19 and has been applied across the BMW model line up. I don't foresee it being an issue as more 48V hybrids and variants will be prevalent moving forward.


G05 48V Electrical System

From November 2019, there will be an extension of the vehicle electrical system capacity in the form of Mild Hybrid Technology with the 1st generation of the 48 V electrical system. For this purpose, new components with 48 volts are used. The new components also result in new functionalities that serve to increase comfort, efficiency and dynamics.

The introduction of the mild hybrid technology results in new functions with the following advantages for the customer:

Reduction in carbon dioxide emissions
Braking energy is not lost, but is recovered electrically (recuperated). The combustion engine is supported while driving and is operated in efficient operating conditions. This results into a reduction in consumption in customer operation by approx. 0.3 l/100 km.

Improvement of automatic engine start-stop function (MSA)
The powerful 48 volt starter motor generator results in a noticeable improvement in the start duration of approx. 20 %. In addition, an improvement in comfort in terms of acoustics and oscillations during the starting procedure is achieved. The starting procedures are barely noticed. The first engine start of the day takes place by the pinion starter motor. If the engine temperature is greater than 60 °C, the combustion engine is started by the starter motor generator.

Coasting with combustion engine switched off
During the so-called engine off coasting, the combustion engine normally no longer runs at idling with the mild hybrid technology, but is switched off. The drivetrain is decoupled in order to use the kinetic energy of the vehicle for movement. This can further reduce fuel consumption by turning off the combustion engine. The engine is restarted virtually without delay by the powerful 48 volt integrated starter/alternator.

Improvement in dynamics by eBOOST
In partial load operation, the starter motor generator supports the combustion engine as an electrical machine. Due to its distortion- free power output, the starter motor generator improves the acceleration behavior, i.e. the spontaneity of the drivetrain. At full throttle, the starter motor generator can temporarily increase the overall power of the drivetrain by 8 kW in certain operating ranges.

With the introduction of the 48 V electrical system, new terminal designations result for differentiation from the 12 V electrical system:
- Terminal 40 = 48 volt positive battery terminal = line color purple
- Terminal 41 = 48 volt negative battery terminal

The 48 volt components are specially marked (ISO standard 6469-3) similar to the high-voltage components.



Starter motor generator
The 48 volt starter motor generator is a control unit. The starter motor generator is an electrical machine. The starter motor generator can work in 2 operating conditions:

- When operated as an alternator, the starter motor generator converts mechanical power from the belt drive into electrical power and feeds this into the electrical system.

- During operation as a motor, the starter motor generator converts electrical power from the vehicle electrical system into mechanical power and transmits this to the belt drive.

The starter motor generator is integrated into the belt drive. The gear ratio starter motor generator to crankshaft is 2.7 to 1.

The starter motor generator is a 5-phase electrical machine. The coolant-cooled power electronics consist of MOSFETs and a microprocessor.

Due to its high power, the starter motor generator requires a cooling system.


48 volt battery (control unit BATT48)
The 48 volt battery is a lithium-ion battery.

The lithium ion battery is installed at the right rear of the engine compartment.

The cell modules consist of nickel, manganese and cobalt on the anode side. A mixture of lithium titanium oxide (LTO) is used on the cathode side.

The working range of 48 volt battery (BATT48) is between -25 °C and 60 °C. The power is reduced at temperatures above 60 °C to 72 °C. The voltage range is from 38 volts to 53 volts.

The control unit 48 volt battery (BATT48) is connected to the K-CAN8.

Due to its high power, the lithium ion battery requires a cooling system.







Power Control Unit 48 volt (control unit PCU48)
The 48 volt Power Control Unit is also a DC/DC converter. The DC/DC converter is the interface between the 12 V electrical system and the 48 V electrical system. The 48 volt Power Control Unit supplies the 12 V electrical system with energy from the 48 V electrical system.

Voltage range at the input is between 24 volts and 58 volts. Voltage range at the output is between 6 volts and 16 volts. The 48 volt Power Control Unit (PCU48) is connected to the K-CAN8.

The flexible energy management and power management, which is in the engine control unit, provides the DC/DC converter with the required output voltage and output current. In the event of a fault, the DC/DC converter itself regulates its control variables.

Due to its high power, the lithium ion battery requires a cooling system.




Power distribution, 48 volts
The 48 volts power distribution is installed e.g. in the left front in the engine compartment.
With the introduction of the 48 V electrical system, new terminal designations result for differentiation from the 12 V electrical system:

- Terminal 40 = 48 volt positive battery terminal = line color purple
- Terminal 41 = 48 volt negative battery terminal
The 48 volts power distribution distributes the terminal 40 to the following components:
- Starter motor generator 48 volts (SGR48)
- Power Control Unit 48 volts (PCU48)

The 48 volts battery (BATT48) supplies the terminal 40 to the 48 volts power distribution:




Cooling system
Due to their high power, the following components of the 48 V electrical system are integrated into the cooling system:

- 48 volt starter motor generator (control unit SGR48)
- 48 volt battery (control unit BATT48)
- Power Control Unit 48 volt (control unit PCU48)






Deactivation executed by crash signal
For safety reasons, the control units 48 volt battery (BATT48) and 48 volt Power Control Unit (PCU48) have a terminal 30C (terminal 30 crash signal). Terminal 30C is disconnected from the 12 V battery in case of a crash from the crash safety module (ACSM).

The voltage drop at terminal 30C leads to an immediate system shutdown. The 48 volt Power Control Unit (PCU48) is shut down. The switching contactor of the 48 volt battery is disconnected under load.

If terminal 30C is accidentally disconnected, this disconnection is automatically regenerated after the connection is re-established. The fault memories in the components document this disconnection.

General notes
When servicing in the workshop, the switch-off is initiated as soon as the hood of the vehicle is opened. This shuts down the 48 V electrical system and remains as it is until the following is detected:

- Close the hood
- PWF status, driving
- External charge

Diagnosis instructions
After having renewed the lithium ion battery, the new lithium ion battery has to be registered. A service function is available in the diagnosis accordingly:

Path: Body > voltage supply > 48 V electrical system > Register 48-V battery

BMW can assume no liability for errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.

[parabola]

Auricom
Thanks for the detailed post. It seems like lot of added complexity for a tiny bit of fuel economy improvement.
Does the sport mod turn off the hybrid system completely?

[Auricom]

Originally Posted by parabola

Auricom
Thanks for the detailed post. It seems like lot of added complexity for a tiny bit of fuel economy improvement.
Does the sport mod turn off the hybrid system completely?

Coding SPORT mode on start up just disables the auto engine start-stop function (MSA). The 48V hybrid system itself isn't disabled as the starter motor generator is integrated with the engine.


The 48 volt starter motor generator is a control unit. The starter motor generator is an electrical machine. The starter motor generator can work in 2 operating conditions:

- When operated as an alternator, the starter motor generator converts mechanical power from the belt drive into electrical power and feeds this into the electrical system.

- During operation as a motor, the starter motor generator converts electrical power from the vehicle electrical system into mechanical power and transmits this to the belt drive.

The starter motor generator is integrated into the belt drive. The gear ratio starter motor generator to crankshaft is 2.7 to 1.


You get the benefits of eBoost:

In partial load operation, the starter motor generator supports the combustion engine as an electrical machine. Due to its distortion- free power output, the starter motor generator improves the acceleration behavior, i.e. the spontaneity of the drivetrain. At full throttle, the starter motor generator can temporarily increase the overall power of the drivetrain by 8 kW in certain operating ranges.

[Delrazdan]

Thanks. Wonderful info.