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Tonight, I connected a Data Logger to the Battery and Series Shunt. I charged it for a bout 1 Hour and Will let it run over night to see if any modules wake up and Drain my battery. So far everything looks good
Earlier while I had Rear Door and Driver side door open, I noticed battery voltage dropped down to 9.9Volts. Then When I closed everything . the battery voltage slowly creeped back up tot 12.2Volts. I have already fixed the wire harness issues on my hatch. Almost looks like there is a problem with door hinges or when the modules start to wake up. This will take me a while to nail. Right now, snowing again. I will look at the DME Fuse box under the hood this weekend. Signs of corrosion?
Tmrw I will try to post the Graph data on what happened tonight.
So, Yesterday I finally was able to connect my data logger to my battery and try to study it. I am not going to brag, I do this stuff for living just its not specialized in Cars. i have access to some cool equipment that I use for Electronics. BMW is a different Animal and I am learning from you guys. Anyway, When I got home, I connected a charger and started the data logger. Let it charge for 1 Hour and you can see how the current is bellow the Zero line. Blue Line. Then I disconnect it and closed everything up, locked the locks and went to sleep. The Car went to sleep and no modules woke up in the middle of the night. Next Morning with 3" of fresh snow on my car, I was happy with battery voltage then I unlocked but not opened the Driver side door. I explained what I was doing. You can see spikes of current then going back to sleep. @ Some point, the battery voltage went to 9.45VDC and stayed there. No significant current draw. This is a 80 Amp Hour + Battery and I should be able to pull 90Amps for 1 Hour . You can figure the ratio out if I am only pulling 4 Amps. The Rate the Battery voltage dropped @ The current it was putting out makes me think that the battery is my problem. On this one at least. I am pulling the battery out and taking it to work tmrw and do a complete Charge and Discharge test to see if this battery is good or not. Its one year old and I got it from Advance Auto. Right now, I am leaning on the battery having a bad cell. The Standard battery load tester I got is not good enough since I need to hold the Load on for more than 1 Minute. I will let you guys know how that goes.
That looks like you system is doing what it is supposed to be doing. You have an 80ah battery. I didn't know they came that small on a 5 series. Looks like you're getting closer to knowing that your battery is the issue. Thanks for the detailed update.
After what happened to me last year I never dismiss an issue being the battery no matter how new. I purchased a battery from Advance auto and the terminals were backwards. Positive was negative and negative was positive. I learned a valuable lesson that day. Always check my batteries with my battery tester before installing and in your case always test battery with load. BMWs are power hungry. It will tell you is something is wrong with the charging system or battery by doing weird things
Last edited by seanjordan20; 02-11-2021 at 06:01 PM.
Probably bigger. I pulled it out and froze my finger. Will take a better look at it tmrw @ work. Its huge. I will be upset if the battery turns out to be my problem. New battery should last 3 to 5 years.
Probably bigger. I pulled it out and froze my finger. Will take a better look at it tmrw @ work. Its huge. I will be upset if the battery turns out to be my problem. New battery should last 3 to 5 years.
I alway get the interstate batteries and they have lasted 7 years for me. I'm on my second one. I think they are 100ah or 105ah and they haven't failed me yet so I stick with it (MTP-49 H8)
Last edited by seanjordan20; 02-11-2021 at 06:43 PM.
Hey I saw some guy on here who wrote a nifty battery testing sticky.
I have access to data loggers too as I work in Engineering.
I wouldn't have gone as far as you did because it never seemed like it was an overlooked nanosecond surge draining the battery. Its entertaining to read your journey nonetheless. I've had new batteries fail on me but I doubt they were new. I also feel "BMW" problems can kill just about any battery. I tackled my low discharge notification after I replaced the battery a few times, replaced the IBS and registered the battery (49EXTJ 49 H8).
02-09-2021, 06:48 PM
