[Watsey]

My F31 330d (2012 build, 115K miles) has a new battery around 20K miles ago - a Bosch 95Ah AGM unit. The battery was coded using BimmerLink but the nearest option was 90AH.

The IBS cable was replaced about a year ago (from memory) but does not seem to have cured the persistent low SOC. Seems to have been a waste of money.

When the car was at a reputable Indy s few months ago to investigate a problem with the aircon (diagnosed as a small leak in the condenser - now replaced by a different Indy) I also asked them to run a full diagnostic. In short, they said there was nothing notable to report.

This evening I had to pick one of my daughters up after an event at school - a round trip of 20 miles. I had BimmerLink connected the entire time and the SOC didn’t increase at all - 54% at the start of the journey and when I returned home. I drove almost the entire journey in Sport manual mode, keeping the revs typically >2000rpm and using a lot of engine braking to put the alternator into energy recovery mode.

This persistently low SOC doesn’t seem right. Suggestions welcomed.

The second problem is more recent and relates to an increasingly frequent reluctance for the engine to start. The brake pedal is often hard after the car has been standing overnight, rather than having some travel at the top of the range. It often requires a VERY firm press before the engine will crank, and as soon as the engine has started the normal small amount of soft travel returns at the top of the pedal range.

I’m assuming this is indicating a leak in the vacuum system somewhere. Thoughts also welcomed on this before I commit yet more money to further diagnostics.

Thanks.

[TurboWeasel]

Might be time to take it to an auto electrician. They have all the proper scopes and test equipment indies don't have. You can check simple things yourself like ground strap condition first though. The one in the driver's side inner arch and the gearbox ground strap both suffer from the green crusties and cause issues.

Reluctance to start could be related. I got a glowplug fault code when the positive cable at the jumper post (red cover on the cowling) was a bit crusty. Cleaned it up and it's been fine since.

[mapyn]

easy to check the running and non running voltage to see if its charging as expected

[NanasBack]

Just thinking out loud here....

If a new battery is fitted with the same rating as the original, you just register it. When fitting a different size battery, it needs to be coded. But does it then need to be registered as well?

Did you register it as well, or maybe that option is not available after coding a new one? Which would answer my question.

I've never changed a battery, but it crossed my mind that, even though it's been coded, if it's not 'registered', the system may retain the original values? Hence seeing not a lot of change in the SOC values.

As for the brake pedal pressure, I often get that and didn't think it's an issue.

[Eddamoo]

On the hard brake pedal, I would agree a minor vacuum leak is the likely culprit here. Cars should have a vacuum reserve which is there in case the engine quits, giving the driver a good 2 further goes at the brake pedal before it's exhausted. This should last at least overnight and I can't recall coming to my car after a prolonged period with a hard pedal.

On the battery SOC, have you tried measuring the battery voltage while disconnected to check it correlates? 54% is probably somewhere between 12.2 and 12.3v.

We had some battery issues on the Mrs' old E89. BMW tried to make out that I was partly to me charging the battery from the boot and the battery management 'not knowing about it' and taking it out of sync. Personally I think it's total rubbish given a resting voltage is all you need to know the SOC, but I'm no expert on that.

[bishbosh]

Originally Posted by Eddamoo

We had some battery issues on the Mrs' old E89. BMW tried to make out that I was partly to me charging the battery from the boot and the battery management 'not knowing about it' and taking it out of sync. Personally I think it's total rubbish given a resting voltage is all you need to know the SOC, but I'm no expert on that.

Newtis does state that battery charging should only be done via the jump start terminals in the engine bay. This is so the ibs can monitor charging voltage.

[bishbosh]

Originally Posted by NanasBack

Just thinking out loud here....

If a new battery is fitted with the same rating as the original, you just register it. When fitting a different size battery, it needs to be coded. But does it then need to be registered as well?

Did you register it as well, or maybe that option is not available after coding a new one? Which would answer my question.

I've never changed a battery, but it crossed my mind that, even though it's been coded, if it's not 'registered', the system may retain the original values? Hence seeing not a lot of change in the SOC values.

As for the brake pedal pressure, I often get that and didn't think it's an issue.

Most bmw batteries will be of the 90Ah agm type. When they are replaced it tends to be with a 95Ah battery since that is the one with the closest Ah rating and it's next to impossible to find one with the original capacity rating.

Even though the new battery has a slightly higher capacity it doesn't need to be coded, only registered. Ista only codes batteries of 90Ah or 110Ah

Coding is only needed when changing battery type between agm and non-agm, and if changing the capacity between to either 90 or 110.

[danb1979]

Originally Posted by NanasBack

Just thinking out loud here....

If a new battery is fitted with the same rating as the original, you just register it. When fitting a different size battery, it needs to be coded. But does it then need to be registered as well?

Did you register it as well, or maybe that option is not available after coding a new one? Which would answer my question.

I've never changed a battery, but it crossed my mind that, even though it's been coded, if it's not 'registered', the system may retain the original values? Hence seeing not a lot of change in the SOC values.

As for the brake pedal pressure, I often get that and didn't think it's an issue.

A like for like battery simple needs registering

A different spec battery needs coding and then registering

This is confirmed by a BMW tech I’ve known for a long time and it’s one thing he said fellow BMW techs forgot and wondered why the owner would come back with battery issues in a few months etc

It’d cost them a new battery and an hours diagnostics etc

[Watsey]

Originally Posted by mapyn

easy to check the running and non running voltage to see if its charging as expected

Yes, I did that during the previous investigation and everything was fine.

[Watsey]

Originally Posted by NanasBack

Just thinking out loud here....

If a new battery is fitted with the same rating as the original, you just register it. When fitting a different size battery, it needs to be coded. But does it then need to be registered as well?

Did you register it as well, or maybe that option is not available after coding a new one? Which would answer my question.

I've never changed a battery, but it crossed my mind that, even though it's been coded, if it's not 'registered', the system may retain the original values? Hence seeing not a lot of change in the SOC values.

As for the brake pedal pressure, I often get that and didn't think it's an issue.

BimmerLink only provides the option to Register a new battery. As per the comment from bishbosh I thought that coding a new battery would only be required if the type of battery was different, i.e. going from AGM to lead acid or lithium.

[Watsey]

Originally Posted by Eddamoo

On the hard brake pedal, I would agree a minor vacuum leak is the likely culprit here. Cars should have a vacuum reserve which is there in case the engine quits, giving the driver a good 2 further goes at the brake pedal before it's exhausted. This should last at least overnight and I can't recall coming to my car after a prolonged period with a hard pedal.

On the battery SOC, have you tried measuring the battery voltage while disconnected to check it correlates? 54% is probably somewhere between 12.2 and 12.3v.

We had some battery issues on the Mrs' old E89. BMW tried to make out that I was partly to me charging the battery from the boot and the battery management 'not knowing about it' and taking it out of sync. Personally I think it's total rubbish given a resting voltage is all you need to know the SOC, but I'm no expert on that.

I'll check the resting voltage again. Charging has only ever been via the terminal posts in the engine bay, as per BMW recommendation.

I think a loss of vacuum is the most likely cause of the hard pedal. Apparently the inlet manifold has to be removed before the necessary checks can be made, so that's a workshop visit rather than DIY for me.

[danb1979]

Originally Posted by Watsey

BimmerLink only provides the option to Register a new battery. As per the comment from bishbosh I thought that coding a new battery would only be required if the type of battery was different, i.e. going from AGM to lead acid or lithium.

Bimmercode to code a new spec battery; Bimmerlink to register it

If you've got one, it's worth having the other IMO

And no; doesn't matter if it's AGM to AGM; if it's say 90Ah to 105Ah; that then needs to be coded to the car and then registered

This is exactly what I did with my previous F01; went from an old OEM BMW 90Ah AGM battery to a Exide 105Ah AGM battery and had to code it first and then register it

[Watsey]

Originally Posted by danb1979

Bimmercode to code a new spec battery; Bimmerlink to register it

If you've got one, it's worth having the other IMO

And no; doesn't matter if it's AGM to AGM; if it's say 90Ah to 105Ah; that then needs to be coded to the car and then registered

This is exactly what I did with my previous F01; went from an old OEM BMW 90Ah AGM battery to a Exide 105Ah AGM battery and had to code it first and then register it

Cheers Dan, I didn't realise that.

I already have BimmerCode as well as BimmerLink - will hook up my phone later and do the necessary. Will be interesting to see whether it makes any difference.

[Watsey]

I connected to the car using BimmerCode last night. When I replaced the OEM 90Ah unit I bought a 95Ah unit, and registered it as a 90Ah AGM. BimmerCode and BimmerLink only have options for 90Ah or 105Ah in the larger capacity range.

[danb1979]

Originally Posted by Watsey

I connected to the car using BimmerCode last night. When I replaced the OEM 90Ah unit I bought a 95Ah unit, and registered it as a 90Ah AGM. BimmerCode and BimmerLink only have options for 90Ah or 105Ah in the larger capacity range.

Yes; 90Ah is the one you go for as it's the closest and that's fine

[TurboWeasel]

Does 105AH fit in the back? Could be a good upgrade

A smoke machine should be able to find the vacuum leak. I got this one when I suspected I had a boost leak - https://www.ebay.co.uk/itm/396017009...hoCo78QAvD_BwE

It quickly proved I didn't but £70 was cheaper than firing the parts cannon at it.

There are quite a few vacuum connections for feeding the EGR valve and vacuum engine mounts etc. The long red one that comes over the top of the injectors likes to crack at the bulkhead end.

[danb1979]

Originally Posted by TurboWeasel

Does 105AH fit in the back? Could be a good upgrade

A smoke machine should be able to find the vacuum leak. I got this one when I suspected I had a boost leak - https://www.ebay.co.uk/itm/396017009...hoCo78QAvD_BwE

It quickly proved I didn't but £70 was cheaper than firing the parts cannon at it.

There are quite a few vacuum connections for feeding the EGR valve and vacuum engine mounts etc. The long red one that comes over the top of the injectors likes to crack at the bulkhead end.

Re battery, IIRC, no. It’s simple too big

I tried to fit one to my previous F01 but it was wider than the brackets that held it down, so that was a no-go

[TurboWeasel]

Ah booo, never mind!

Even with a new battery and in winter, some electrical items like the wipers and steering rack feel a bit a sluggish until the alternator has run for a couple of minutes. So I think these cars would benefit from more electrical ooomph.

Talking about the diesels there. The petrols are fine on the whole.

I can't remember where I read it but I'm sure someone mentioned these cars behave better with the OEM BMW batteries. Varta aren't they?

[danb1979]

Originally Posted by TurboWeasel

Ah booo, never mind!

Even with a new battery and in winter, some electrical items like the wipers and steering rack feel a bit a sluggish until the alternator has run for a couple of minutes. So I think these cars would benefit from more electrical ooomph.

Talking about the diesels there. The petrols are fine on the whole.

I can't remember where I read it but I'm sure someone mentioned these cars behave better with the OEM BMW batteries. Varta aren't they?

Varta, Banner and Exide are now all OEM

[Watsey]

Originally Posted by TurboWeasel

Does 105AH fit in the back? Could be a good upgrade

A smoke machine should be able to find the vacuum leak. I got this one when I suspected I had a boost leak - https://www.ebay.co.uk/itm/396017009470?var=0&shprz=EBAY_GB_131090&_ul=GB&_tr kparms=ispr%3D1&amdata=enc%3A125kycHtDThGfisZJujwk mQ10&mkevt=1&mkcid=1&toolid=20006&mkrid=710-53481-19255-0&campid=5338986375&customid=CjwKCAiA65m7BhAwEiwAA gu4JPB0hhxmFbAbYWPSlCtcNfkN1010XIy6VEnf5Ly45xdmiWS E6U6z9hoCo78QAvD_BwE&gbraid=0AAAAADcddna8_9H0clhL9 4X-U40ukdc80&gad_source=1&gbraid=0AAAAADcddna8_9H0clh L94X-U40ukdc80&gclid=CjwKCAiA65m7BhAwEiwAAgu4JPB0hhxmFb AbYWPSlCtcNfkN1010XIy6VEnf5Ly45xdmiWSE6U6z9hoCo78Q AvD_BwE

It quickly proved I didn't but £70 was cheaper than firing the parts cannon at it.

There are quite a few vacuum connections for feeding the EGR valve and vacuum engine mounts etc. The long red one that comes over the top of the injectors likes to crack at the bulkhead end.

I’m increasingly convinced it’s a vacuum leak. The hard pedal and difficulty starting the engine are now almost daily problems. I also wonder whether there’s a secondary problem, as I’m also having to use a jump pack for the initial crank if the engine (and it then fires immediately).

Apparently the IM has to removed to get to the vacuum pipes and connections, in which case this will be a paid job in the early new year. I don’t fancy all that work, and it’s not something I’ve done before.

I have t checked the earth binding straps yet, but that’s something I can check once we’ve got the Christmas madness behind us.

[Watsey]

Originally Posted by TurboWeasel

I can't remember where I read it but I'm sure someone mentioned these cars behave better with the OEM BMW batteries. Varta aren't they?

A different Indy told me that they’ve had several instances where charging and SoC problems have been fixed by changing the battery for an OEM unit.

I’d assume that all AGM batteries are fundamentally the same, i.e. AGM rather that conventional lead acid, (obviously there are differences in Ah and CCA) and don’t have an integral BMS which could be at odds with the vehicle control systems, but perhaps not.

[danb1979]

Originally Posted by Watsey

A different Indy told me that they’ve had several instances where charging and SoC problems have been fixed by changing the battery for an OEM unit.

I’d assume that all AGM batteries are fundamentally the same, i.e. AGM rather that conventional lead acid, (obviously there are differences in Ah and CCA) and don’t have an integral BMS which could be at odds with the vehicle control systems, but perhaps not.

I’ve never had issues with non OEM BMW batteries. For me there’s something else afoot.. wonder if the IBS cable is at fault.

Do you know anyone with the likes of ISTA etc?