Battery madness

[Z8cookie]

Not one YouTube video, not one written article, not one battery seller appears to be aware that the battery fitted in a M4 has an extra connection besides the main +&- terminals, and possibly many others since 2002 I gather. So when your new replacement battery arrives (at £500 cheaper the the OEM, a battery is a battery right, as long as you’ve bought a good brand?) and you come to fit it, you discover the small 2 pin plug that connects to the “intelligent battery sensor” that isn’t mentioned. So can you fit this different battery or not? Yes, you don’t have to use the exact same battery as long as you enter this information at the time of registration of the battery change says every article or video, but what about the little 2 pin intelligent battery sensor cable? Does the car ignore it now if you updated the software information to a different battery without the sensor? I don’t know, no one mentions this point. If you’ve come across this issue and discovered the answer I would love to know as I don’t want to screw up the car’s electrics and I’m pulling my hair out trying to find someone that has the answer.

[helix402]

It’s quite straightforward:

It’s called IBS (not the digestive system issue).

I think it arrived with the E65. A long time ago.

With IBS: new battery same amperage as the one-registration only.

New battery: different amperage (eg 90A not 80A): registration and coding.

[CoolHands]

Doesn’t it just need a wire to connect it to the negative? You could fashion something I’m sure. If you leave the IBS disconnected it means the alternator will always output the full 14.2v and not vary it as it would do normally, is my understanding.

[Z8cookie]

CoolHands said:

Doesn’t it just need a wire to connect it to the negative? You could fashion something I’m sure. If you leave the IBS disconnected it means the alternator will always output the full 14.2v and not vary it as it would do normally, is my understanding.

Unfortunately I doubt it, it’s a small 2 pin connection on the side of the battery that feeds the “information” from the battery to the car, this is my point, without this connection how does the car “manage” the charging rate/voltage etc, or if it’s left disconnected will it just output the full 14.2v as you suggest, and if so what are the consequences to the “modern” over sensitive electronic devices and systems? Or is this taken care of when a different battery is registered to the car?

Edited by Z8cookie on Thursday 4th August 08:29

[Z8cookie]

helix402 said:

It’s quite straightforward:

It’s called IBS (not the digestive system issue).

I think it arrived with the E65. A long time ago.

With IBS: new battery same amperage as the one-registration only.

New battery: different amperage (eg 90A not 80A): registration and coding.

Thanks but, unfortunately that doesn’t answer the question.
How can the IBS work with a different battery with nowhere to connect the data cable?
If a different battery is fitted without the IBS connection, once registered and coded does the car ignore the IBS and the extra cable can be ignored?
What are the possible consequences of not using a “monitored & managed” battery to the other systems in the car?

[CoolHands]

Can you post pics of the 2 pin connection? And the wiring and even the old battery if you still have it with the extra bit. As far as I can see they all connect directly to the battery negative. Maybe you need to check your wiring is OEM. or check you have latest version of the IBS. If yours has been messed about with then just buy new part.

Leaving it disconnected won’t damage anything (ie so it will just be outputting max all the time). Vague possibility it could damage the longevity (life) of the battery but in my opinion unlikely as that’s how all batteries operated before their IBS idea. They introduced it to save energy.

Edited by CoolHands on Thursday 4th August 10:07

[Z8cookie]

CoolHands said:

Can you post pics of the 2 pin connection? And the wiring and even the old battery if you still have it with the extra bit. As far as I can see they all connect directly to the battery negative. Maybe you need to check your wiring is OEM. or check you have latest version of the IBS. If yours has been messed about with then just buy new part.

Leaving it disconnected won’t damage anything (ie so it will just be outputting max all the time). Vague possibility it could damage the longevity (life) of the battery but in my opinion unlikely as that’s how all batteries operated before their IBS idea. They introduced it to save energy.

Edited by CoolHands on Thursday 4th August 10:07

Yep all original and as should be, had it from new and this is the first time I’ve had to change the battery. It only when I came to remove the old one I discovered the extra small 2 pin connector on the side of the battery. Obviously this is why the OEM replacement is £800+ The cable appears to be completely separate from the maim terminals. The vent connector is going to need modification as well. Surely someone else has encountered this problem, I can’t be the first one to try and replace the original battery with a similar but different brand.

[CoolHands]

Ok it seems there is more to your story. Is the original a lithium-ion battery? And you have replaced with AGM battery? Maybe this thread or similar will help. It seems you might have to replace your neg battery cable with one from a different non lithium ion vehicle, that does have IBS. So it is probably possible. But you will have to search bmw forums for more info. Maybe you can get your original battery working, why did you change it.

https://f80.bimmerpost.com/forums/showthread.php?t...

https://m.youtube.com/watch?v=KHL78-pvlvs&feat...

Edited by CoolHands on Thursday 4th August 11:35

[Z8cookie]

CoolHands said:

Ok it seems there is more to your story. Is the original a lithium-ion battery? And you have replaced with AGM battery? Maybe this thread or similar will help. It seems you might have to replace your neg battery cable with one from a different non lithium ion vehicle, that does have IBS. So it is probably possible. But you will have to search bmw forums for more info. Maybe you can get your original battery working, why did you change it.

https://f80.bimmerpost.com/forums/showthread.php?t...

https://m.youtube.com/watch?v=KHL78-pvlvs&feat...

Edited by CoolHands on Thursday 4th August 11:35

Thanks for the help. Yes I’m changing the battery from the very expensive lithium to a AGM. The original isn’t holding a full charge and causes a warning light permanently on the dash.

[Z8cookie]

Take my advice. Don’t try it. Just returned the (much cheaper) AGM battery and ordering an original replacement at £800 ish. Because I’m running out of hair.

[CoolHands]

Yeah I can imagine. I guess you get stuck with some of these newfangled ideas. Save 1kg in weight but cost 800 quid! Probably cheaper going into space per kilogram.

[Z8cookie]

CoolHands said:

Yeah I can imagine. I guess you get stuck with some of these newfangled ideas. Save 1kg in weight but cost 800 quid! Probably cheaper going into space per kilogram.

Found a great article that covered the smart features of the battery and IBS system, but can’t find it again now. The battery is a fraction of the weight of a AGM and the alternator only charges it when not accelerating only when slowing down etc. so the petrol saved and increased performance must be well worth the extra cost of this battery.
(Can’t find rolling eyes emoji)