[Per Hansson]

I was coding my new FRM2 module yesterday and dropped the battery charge too low so the car wouldn't start.
So I disconnected the negative cable from the battery and connected a charger overnight, now I read afterwards this is not recommended due to the IBS system.

So I thought I would reset the battery histogram in INPA, but before reconnecting the cable I noticed that in my E90 built 2006 there is no IBS sensor on the negative cable.
So what gives, only some cars have it? If there is no sensor is there also no need to register a new battery if it's replaced?
My battery is probably the original so over 7 years old now, still works great tho, touch wood!
It is registered properly in the vehicle order, I see "-B070" which corresponds to my 70Ah wet battery...

[Per Hansson]

I took some screen grabs now with INPA as the charging was finally completed.
Seems there really is no IBS, so question then becomes are some cars sold without it or have someone stolen mine lol?

[Meeni]

The IBS is on the positive cable. You have one, it's the large flat black plastic box on top of the battery. Do not disconnect the battery to charge it. There are 2 posts in the engine bay for that (the red under a plastic cover, and a hexagonal neutral sticks out from the left framepost, see your user manual if unsure).

[Augster]

Originally Posted by Meeni

Do not disconnect the battery to charge it. There are 2 posts in the trunk for that (the red under a plastic cover, and a hexagonal neutral sticks out from the left framepost, see your user manual if unsure).

Um, did you mean "engine compartment" instead of "trunk?"

My cart-mounted battery charger can't charge the battery via the dedicated posts in the engine compartment; I have to go directly to the battery.

Then again, my alternator is supposedly bad (waiting for a replacement, hence the need to charge the battery in the interim) so I'm not sure if that has something to do with the inability to charge the battery from the engine compartment.

[Meeni]

Originally Posted by Augster

Um, did you mean "engine compartment" instead of "trunk?"

My cart-mounted battery charger can't charge the battery via the dedicated posts in the engine compartment; I have to go directly to the battery.

Oups yes, engine bay.

This is not normal. Charging the battery happens from the engine bay, if it doesn't work something is wrong with the harness.

[Augster]

Originally Posted by Meeni

This is not normal. Charging the battery happens from the engine bay, if it doesn't work something is wrong with the harness.

The PO put in an Super Start aka O'Reilly Auto Parts 790CCA battery, and I seriously doubt he had it registered nor programmed (if wasn't the same spec as the OEM, which not even my local BMW dealers' parts department was sure of even when he pulled up my VIN but still asked that I bring in the original OEM battery to compare specs): could that be a potential cause for the system not charging the battery from the terminals, and perhaps even why the alternator is not charging the battery?

I was able to drive the car to O'Reilly to get them to test the alternator, and according to their diagnostic tool, the voltage regular is working, but the diodes were not, ergo the alternator was bad. Since the meter was attached to the front power posts, I'm assuming the measurements were of the alternator output. The car certainly will run just fine from the battery so this would seem to indicate the battery cables are fine, but of course, it's not getting charged by the alternator so I can go about 5-8 miles on a full battery charge before the cars' electronics going haywire (instrument cluster lights up all kinds of different warnings) and the car will no longer move nor start once stopped.

I am waiting for the oft recommended INPA/Ediabas K+CAN USB cable from One Stop Electronics (I didn't realize it's shipping direct from Hong Kong, which now makes me wonder what makes it different from other Chinese cables that are vastly cheaper); I already have the BMW Scanner 2.2 from XCar360 but it doesn't appear to provide battery management for the E90.

I'm just not sure where to reliably get the latest software to utilize the K+CAN cable...

[Efthreeoh]

Originally Posted by Meeni

The IBS is on the positive cable. You have one, it's the large flat black plastic box on top of the battery. Do not disconnect the battery to charge it. There are 2 posts in the engine bay for that (the red under a plastic cover, and a hexagonal neutral sticks out from the left framepost, see your user manual if unsure).

This is incorrect. The IBS is not on the positive cable. The IBS is built into the negative battery cable. The positive battery cable has the Battery Safety Terminal (BST) harness built into it (it's the red box covering the positive battery terminal). The BST has small explosive charges built into it to disable most of the car's circuits in case of an accident to prevent fire. The BST maintains voltage on critical circuits such as the interior lights, door locks, and flashers once it is triggered by an accident.

The IBS monitors battery health, parasitic current draw, and determines charging rates. The BST has a small black box (with a metal plate) and a wire harness and connector. I checked realOEM for a European 325i and it looks like all cars come with an IBS. The IBS determines when to shut down specific circuits to maintain a minimum level of charge to be able to start the car. It would seem to me BMW would have to have two different electrical system designs if the car did not have an IBS; which would be cost prohibitive from a design and manufacturing perspective.

[bob.g]

ive read many posts saying registration isnt required on the 06. There is even free software you can use to register your battery (http://**************.com/bmwlogger) and many 06 owners have reported that it wasnt working on their car.

[Per Hansson]

Efthreeoh: everything you wrote is correct.
I even looked up my VIN on bmwfans.info earlier today and there too I can see the IBS as a spare part for my car...
But what bob.g says I've read aswell, and well a picture is worth more than a thousand words. (You can click it for a larger version)
Question: when you have the IBS is it visible in the vehicle order in NCS Expert?

[dkexige]

Originally Posted by Efthreeoh

The IBS is not on the positive cable. The IBS is built into the negative battery cable....

Super informative. Thanks!

[taibanl]

I do not have ibs

[Meeni]

Originally Posted by Efthreeoh

This is incorrect. The IBS is not on the positive cable. The IBS is built into the negative battery cable.

I stand corrected. Thanks for taking the time to be so informative.

[Efthreeoh]

Originally Posted by Per Hansson

Efthreeoh: everything you wrote is correct.
I even looked up my VIN on bmwfans.info earlier today and there too I can see the IBS as a spare part for my car...
But what bob.g says I've read aswell, and well a picture is worth more than a thousand words. (You can click it for a larger version)
Question: when you have the IBS is it visible in the vehicle order in NCS Expert?

By that picture, you do not have IBS. I guess they can program the functionality out of electrical system. Consider yourself lucky then, no battery coding and no chance of breaking a $200 part. Or, apparently you are not the original owner it seems, so maybe the previous owner broke the OE IBS and replaced it with a straight cable.

[Efthreeoh]

Originally Posted by Meeni

I stand corrected. Thanks for taking the time to be so informative.

I wasn't flaming (hope you didn't take it that way), I wanted to make sure everyone knew the IBS is the negative cable. It does get confusing sometimes with all this fancy BMW over engineering (I too had it confused myself for a while).

[Per Hansson]

Yes very informative Efthreeoh
I just had a look in a friends E90, built 2005
It also does not have the IBS so I guess it's normal in old cars.
Maybe only available from 2007 and onwards?
Or depends on how many modules you have, like iDrive and so on? Or maybe if the car has stop-start system or not?
What's strange is that my car has for example ACC so I have the "rest" feature.
Obviously using that too much could drop the charge too low so the car wont start.
As I found out the hard way when playing with the FRM2 module there really is no low battery warning on my car...
The good news is that after a full charge and clearing all warnings with INPA there are no warnings anymore, airbag, ABS etc is happy now, and the FRM2 is working great too

[Meeni]

My car is build 9/05, and it has an IBS. However, the BST unit is not the same as yours (from pure visual inspection), so maybe euro and US spec BST/IBS are different.

[alexwhittemore]

According to WDS, IBS is in all the diagrams for all E90 model years. The brown cable and exposed terminal clamp in your picture strongly suggest to me someone didn't know what to do with it and/or broke it and simply replaced the cable without it. All the diagnostic documentation in WDS, however, suggests the possibility of IBS not being fitted, so maybe it IS, in fact, a cost saver in some models in some markets.

[Per Hansson]

Originally Posted by Meeni

My car is build 9/05, and it has an IBS. However, the BST unit is not the same as yours (from pure visual inspection), so maybe euro and US spec BST/IBS are different.

Well my friends BST is different, it is black instead of red...
The connector is there in my BST for the blue IBS cable, you can see a small part of the blue sticker under the metal bar right above the yellow sticker...

[taibanl]

Originally Posted by alexwhittemore

According to WDS, IBS is in all the diagrams for all E90 model years. The brown cable and exposed terminal clamp in your picture strongly suggest to me someone didn't know what to do with it and/or broke it and simply replaced the cable without it. All the diagnostic documentation in WDS, however, suggests the possibility of IBS not being fitted, so maybe it IS, in fact, a cost saver in some models in some markets.

2011. No ibs

[davidlo19a]

Hello, I am new here, and I know this is an old post, but..

I drive a 2007 E90 320D, which I had the battery replaced recently (1st battery replacement), and noticed that my car didn't come with IBS on the negative terminal.

Recently, I got my INPA cable and ran the error codes, I noticed a:
4A27 - Intelligent Battery Sensor
error in the codes.

I know my car didn't come with IBS, but should it throw the code, or simply be disabled somewhere else?

I guess this post is directed at Per Hansson, does your car also give IBS error code when you scan for error codes?

[Per Hansson]

Hi, no my car does not have that error code.
Check your Vehicle Order for what type of battery is registered.
And check if maybe there is an entry for the IBS in the VO aswell?

[davidlo19a]

I'll check the VO for the type of battery registered soon.
And, I wonder what's the VO code for IBS?? Would anyone know?

And, thanks to Per Hansson for the info.