Battery Voltage is dropping to 11V overnight

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12-10-2013, 01:48 PM

#21

BimmerFan52

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Quote:

Originally Posted by jcolley

If IBS is preventing the system from going to sleep, there will be an "increased battery discharge" error in iDrive when Terminal 15 power comes on. Unplugging the BSD line connector from the IBS sensors may cause BSD bus faults to be stored, but I'm not certain if it will prevent the modules from going to sleep.

I'll have to look through the E60 training docs.

If the IBS senses a negative net flow of current (more current leaving the battery than entering it to charge) it can wake up the DME, which is designed to be a one-time event. The DME can, if the car is at rest, shed load by turning off certain power consumers in the system.

After the one-time event a properly functioning IBS will continue to monitor SoC and SoH, but it will not again wake up the DME.

Early IBS units 2003-2006 were not properly waterproofed and water damage has been know to cause the IBS to malfunction and repeatedly wake up the DME, causing a significant parasitic drain.

If the IBS is disconnected the DME falls back to a default charging scenario. The DME will not longer be awakened.