Strange battery issue with MY08 X5 3.0si

[koolkat1973]

My issue started about a month ago. I swapped new battery on my X5 back in Nov 2014 at 64K miles with a brand new AGM 90AH battery from Advance Auto Parts. I registered the new battery and confirmed that the it's set to 90ah_agm using NCS. So about a month ago, my X5 would not start at all and it would give all these Error code on the dash. I would tried to start it again and same issue. Then I would wait several minutes and tried again and it would start with no problem. So I thought it was fluke and everything was back to normal. Everything was good for about several weeks and then same thing happened 2 days ago. Drove to my son's soccer game and when we got back into the car to start it up, it did the same as before. Waited a little and then it wouild start again. It's been doing this the past several attempt.

Last night and into this morning - I have plugged in the cable to have been monitoring my battery using INPALOAD. My only issue is that I'm not sure I know what I'm reading. I'm hoping an expert on this forum can shed some light to what I'm looking at and can help me figure out what my issue is. I don't think it's battery since this this battery is only 6 months ago.

Does anyone know how to interpret these readings below? Thank you.

[Chris F.]

Hopefully someone else will reply, but your IBS may be going out. When the car doesn't start, try unplugging the IBS (on the negative terminal) and see if it starts up. I believe it's a small light blue plug on the negative terminal.

[pshovest]

I've read that disconnecting the IBS has helped some cars start. It seems like the IBS won't let car start if battery charge is too low or the IBS BELIEVES it is too low. The IBS keeps track of discharge and charging energy. First screen seems to show this. SOC is State Of Charge of battery. Seems strange that a new battery only has 30% start capacity. There's a .pdf somewhere describing the incredible complexity of the electrical charging system. Can't seem to find it right now.

[koolkat1973]

Thanks for the prompt reply. So from what you're seeing in my screenshots, does it look like my battery is not sufficiently charged? Thanks.

[14thbmw]

I think I would put a charger or tender on the battery and make sure it is "topped off" then take fresh readings, then drive and get updates. Just to have a solid baseline.

The IBS and voltage regulator(alternator) are suspects, assuming all is well with the battery connections and coding.

[bawareca]

From what I have read, with bad IBS the ignition will not turn at all. It will turn on and the car will start after IBS is disconnected. At least on E6x. I may be mistaken though as I dont have personal experience with such a problem.
70% charge of the battery is not bad if the car is driven in city cycle.

[mart_dev]

Very late reply and possibly not relevant but an often overlooked "battery problem" is a tracker unit fitted years ago by a previous owner. The batteries on the average tracker doesn't last more than a few years in real world conditions and once it's lost the ability to hold a charge it creates a high drain condition on the vehicle battery. Worth checking out. Can be difficult to locate since the units are intentionally hidden away. Not sure this helps you but may help others down the line. A good first step would be to verify whether or not a tracker unit is fitted in the vehicle (national database perhaps?)

[jfoj]

Originally Posted by pshovest

I've read that disconnecting the IBS has helped some cars start. It seems like the IBS won't let car start if battery charge is too low or the IBS BELIEVES it is too low. The IBS keeps track of discharge and charging energy. First screen seems to show this. SOC is State Of Charge of battery. Seems strange that a new battery only has 30% start capacity. There's a .pdf somewhere describing the incredible complexity of the electrical charging system. Can't seem to find it right now.

http://www.bmwmotorsports.org/pdf/e7...0and%20Bus.pdf