The insanity of modern cars

[Barry]

Don't know if anyone has a modern BMW car and has experience that can help me with this.

My son has a 1 series BMW which has been left with me while he is on holiday in Spain. He said the battery is on it's last legs after less than 18 months so I've set out to investigate.  

I've been charging it and monitoring the voltage over a few days and there is no question it's knackered (technical term).
It turns out modern BMW cars have some sort of intelligent charging system which varies the charging voltage according to battery type, AGM or standard, battery capacity and even how old it is. All of this means you can't just replace the battery as a DIY proposition. The battery has to be registered in the engine management system and even reprogrammed if for example the type has changed to AGM. Failure to do this can destroy a new battery in a little over 12 months. So I'm guessing this reprogramming wasn't done when the battery was last changed and the implication is you have to take it to a BMW dealer for a new battery.  You can just imagine what that is going to cost. I've seen £250 or $350quoted to fit a new battery.

All I know so far is the battery is being charged at 14.5 volts at idle ! (eat your heart out airheads).  I'm going to hook up a digital meter to monitor voltage while I drive it and see what that produces. Not hard to imagine it will be higher and that may explain the shortened battery life.

The more I learn about modern cars the more insanely complex and horrifyingly expensive they seem to be.  I'll be sticking with my 25 year old Merc.  

 

[clonmore1]

Insanity only from the owners perspective, the manufacture designs in revenue generating elements of the car and feeds off that for as long as possible...

[Bob_Roller]

I've got an '01 Z3 3.0 and it doesn't care what type battery you put in it .

It came with a standard ' flooded ' battery and is on it's second AGM type with no issues .

I have a Bentley repair manual for it and unless you have the factory diagnostic tooling, you're pretty much lost !!!

I do recommend the Bentley repair manual it's worth the cost, around $100US when I got it in '02 .

[Barry]

Bob,

I think they started with this intelligent battery monitor in the mid 2000's so you only just escaped having it.

The principle is not an bad one in theory as it would have automatically adjusted the charging regime to suit an AGM but you have to program it to do so at great expense and  then theory doesn't always hold up in practice as instead of protecting the battery it seems it can also destroy them even to the extent of the battery exploding.  It was common for the early sensor to fail often taking the battery with it and just fitting a new sensor costs several times as much as a new battery.  

It's a nonsense and I'm currently trying to find out what happens if the sensor is disconnected. I've seen something that suggests that the maximum charging voltage would then default to a safe figure of 14.3 volts.



“Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius — and a lot of courage to move in the opposite direction.”
[ch8213] E.F. Schumacher
  

[Ed Miller]

I have a Bentley repair manual for it and unless you have the factory diagnostic tooling, you're pretty much lost !!!

I do recommend the Bentley repair manual it's worth the cost, around $100US when I got it in '02 .

What good is a Bentley repair manual when you're working on a Bimmer?

[Bob_Roller]

Bentley Publishers, kinda like a Clymers, Haynes, etc ...

http://www.bentleypublishers.com/bmw/

One of the best manuals I've ever had .

I think Monte has mentioned he has one for his VW .

[montmil]

... One of the best manuals I've ever had. I think Monte has mentioned he has one for his VW.

Roger that, Bob.

I also have a Haynes for the Cabriolet but the Bentley is my primary go-to shop manual. They are somewhat pricey, but the first time I used it on a larger Cabrio project, it paid for itself.

[nhmaf]

Definitely some marketing & sales guys had the engineers design that "feature" in that required the garage to select the battery type via a secret, hidden parameter in the diagnostics system - complete rubbish!
They could as easily have had the system monitor the voltage and charge current and adjust the charging accordingly, or simply allowed the user the ability to set it from inside the car -- or, heaven forbid, simply use a wet-cell friendly charge rate profile and lived with the longer charge times for the batteries.  

When we get to Lipo batteries in cars, this is only going to get worse..

[Lucky_Lou]

Its a bit like the plastic oil pump housing on my ford..... it nearly cost me the engine when it cracked !!!! who ever thought that one up total muppetry.
Lou

[MrRiden]

bmwcoding.com may have a solution.