Quote:
Originally Posted by Billfitz
The easiest way to find parasitic draw is with an ammeter. There are youtube videos that show how.
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The mystery deepens.
So I bought a 10amp charger/maintainer (the NOCO Genius10), left it to charge the car up overnight (so I could make everything would be "on" as normal, instead of the car putting itself in protection mode every 30 seconds). According to the lights on the NOCO this morning, the battery was at a normal state of charge (green light).
I went through the fuse testing process (guided by
this excellent video). First I made sure the car was in "normal" power mode (lights would come on when I opened the door, etc), then I latched all the doors and trunk using a screwdriver, locked it, and let it go to sleep.
After measuring all the fuses, I found two of them drawing current:
Fuse 104 (door locks) - 13 mA
Fuse 120 (radio) - 73 mA
Obviously the radio one is above the sleep target (around 35 mA). So I pulled it, and went to run some errands which meant about a 15 minute drive.
Keep in mind that the battery was supposedly fully charged prior to this drive. I got to my destination, locked the car, and when I came back to it...it was in low power mode again, evidenced by the keyless access not working. Upon startup, it again complained about discharge while stopped.
I plug in my WiFI ENET adapter and fire up BimmerLink, and it says that the battery state of charge is only 19%! What the hell.
I attempt to clear all codes using Bimmerlink, and a new (well, old, but I hadn't seen it in months) error about an Emergency Call Malfunction popped up. I had seen this months ago, ordered a new SOS battery (special $65 battery), but by the time the battery arrived the message had gone away, so I didn't bother to replace it. Well, today I replaced it. After doing that, I attempted to clear the codes again, but the ones related to the SOS issue keep popping up, and the car is still complaining about a low state of battery charge.
So as of now, it's plugged into the NOCO charger again (which when I first plugged it in does indeed appear that the battery is down around 25%, but within 20 minutes it registers as full). I tested all the fuses again and found none that were pulling current aside from 104 at 13mA.
I'm hoping that getting it a nice full charge after replacing the SOS battery will take care of this -- maybe the old dead SOS battery was messing with the main battery? Seems weird but I have no other theories right now.