48 Volt Battery Maintenance (SI B61 01 21)

48 VOLT BATTERY MAINTENANCE

TECHNICAL SERVICE BULLETIN

SERVICE INFORMATION

This Service Information Bulletin (Revision 3) replaces SI B61 01 21 dated July 2021. 

What's New  (Specific text highlighted):

• MODEL, new models added
• PROCEDURE, revision

SITUATION

48 V battery may become totally discharged, and possible replacement needed if:

1. The vehicle has been charged using a 12 V charger with the hood closed during a long stationary period, the. For example, the showroom or storage.
2. Vehicles stored for an extended period connected to a low output solar or trickle charger.
3. Vehicles stored for an extended period with no charger connected and not properly maintained 12 V battery.

Fault memory:

• 803419 - Batt48: Total discharge
• 803408 - Batt48: Emergency announcement: Cell voltage too low
• 803437 - Batt48: Cell defect - total discharge

CAUSE

1. The 48 V battery does NOT charge when using a 12 V battery charger with the hood closed. When charging the vehicle using a 12 V battery charger, the 48 V battery is ONLY able to charge with the hood open.
2. Trickle chargers and solar chargers may not be able to properly maintain the 48V battery.
3. Prolonged used of the "Emergency charging function"  causes the 48 V battery to become totally discharged. This occurs when the 12 V battery is not properly maintained and the SOC of the 12 V battery drops below the critical threshold value while the vehicle is in sleep mode. The vehicle is woken up and recharged from 48 V battery. If the 12 V battery is not properly, maintained this cycle repeats until both batteries become totally discharged.

PROCEDURE

In order to prevent total discharge and thus preliminary damage to the 48 V battery the following steps can be use:

1. a) For vehicles in the showroom or vehicles stored while connected to a permanent 12 V charger: 

   Prerequisite:  Vehicle is connected to 12 V permanent charger (for example in the showroom, whereby the 12 V charging cable is routed into the engine compartment via the vehicle underside, in order to close the hood.

   Option 1: 

   In this case, an external battery charger must be activated every 48 to maximum 55 hours at the latest. Then open the hood for at least 2 hours.

   Option 2: 

   Disconnect the mains/signal connector G14*1B  of the BATT48 (see attachment).

   IMPORTANT: The 12V battery must be fully charged before unplugging the 48V signal connector.

   Subsequently the hood can be closed.

   Before the vehicle is driven again on the road, it is important to plug in the connector delete the fault memory using ISTA.

   This is an option if the vehicle is standing in the showroom or stored for an extended period with or without a charger (maximum of 12 months) and is not driven.

   NOTE: The 48 V battery is not required for demonstration of various vehicle functions in the showroom.
2. For vehicles stored for an extended period of time and proper maintenance of the 12 V battery cannot be guaranteed, disconnecting connector G14*1B  can prevent damage of the 48V battery.

Refer to  SIB B61 18 08  for 12 V battery maintenance information and battery log. 

QUESTIONS REGARDING THIS BULLETIN

Technical inquiries	Submit feedback at the top of this bulletin
Warranty inquiries	Submit an IDS ticket to the Warranty Department or use the chat available in the Warranty Documentation Portal
Parts inquiries	Submit an IDS ticket to the Parts Department

Supporting Materials

picture_as_pdf B61 01 21 Attachment January 2021.pdf 

Courtesy of BMW OF NORTH AMERICA, INC.