E70 Increased Battery Discharge while Stationary

[RRE70]

Originally Posted by Penguin

Of course. I am a firm believer in reading manuals.

[Penguin]

Originally Posted by RRE70

I agree. I think it is a German thing (....) They know they make good products, but when something is wrong they just can not believe it is true.... Could it be arrogance...?

Perhaps. But maybe just plain old stubbornness...

For a decade (or more) in the 1970's/early 1980's, BMW used spring-loaded sidestands on their motorcycles. Everyone constantly complained as it is quite difficult to hold the sidestand out with your left foot while gently tilting the bike onto it. BMW's answer was that a proper rider should dismount the motorcycle to the left before putting the sidestand down.

Think about it. Particularly when you are touring and have sidecases and a bunch of stuff strapped onto the rear of the seat.

It was so bad that there were at least 3 companies selling replacement sidestands that bolted onto the frame, were ugly, and costly ($75-150 in 1981 dollars). Yet, they sold a lot of the ugly things, including one to me, because of the bad BMW design.

BROWN Sidestand BMW R100RS,R75/5,R100S,R80RT,R90S,R80/7 - eBay (item 380299314100 end time Jan-13-11 10:49:41 PST)

Finally when they came out with the K series of bikes they stopped using spring--loaded sidestands... it only took a decade for their customers to pound it into the engineers' heads.

In the early 1990's when BMW added power-hungry ABS systems, the bike began having under-charged battery problems. BMW blamed it on the riders taking too many short trips and/or keeping the engine RPMs too low. Sound familiar?

It got to the point that they were giving a free BMW 3 amp battery charger with every new motorcycle (I got one with my 1991 K75S). After 2-3 years of this, they stopped giving away the free battery chargers and no one had any charging problems. Oh, and there was a new, larger alternator attached to the engine when they stopped giving away the free battery chargers.

BMW representatives and presenters at the BMW National rally never, ever admitted there was a problem with the sizing of the charging system. I suspect if you asked them today, they would still deny it, and blame it on the riders' riding style.

[SJCFlyer]

Originally Posted by Penguin

Perhaps. But maybe just plain old stubbornness...

For a decade (or more) in the 1970's/early 1980's, BMW used spring-loaded sidestands on their motorcycles. Everyone constantly complained as it is quite difficult to hold the sidestand out with your left foot while gently tilting the bike onto it. BMW's answer was that a proper rider should dismount the motorcycle to the left before putting the sidestand down.

Think about it. Particularly when you are touring and have sidecases and a bunch of stuff strapped onto the rear of the seat.

It was so bad that there were at least 3 companies selling replacement sidestands that bolted onto the frame, were ugly, and costly ($75-150 in 1981 dollars). Yet, they sold a lot of the ugly things, including one to me, because of the bad BMW design.

BROWN Sidestand BMW R100RS,R75/5,R100S,R80RT,R90S,R80/7 - eBay (item 380299314100 end time Jan-13-11 10:49:41 PST)

Finally when they came out with the K series of bikes they stopped using spring--loaded sidestands... it only took a decade for their customers to pound it into the engineers' heads.

In the early 1990's when BMW added power-hungry ABS systems, the bike began having under-charged battery problems. BMW blamed it on the riders taking too many short trips and/or keeping the engine RPMs too low. Sound familiar?

It got to the point that they were giving a free BMW 3 amp battery charger with every new motorcycle (I got one with my 1991 K75S). After 2-3 years of this, they stopped giving away the free battery chargers and no one had any charging problems. Oh, and there was a new, larger alternator attached to the engine when they stopped giving away the free battery chargers.

BMW representatives and presenters at the BMW National rally never, ever admitted there was a problem with the sizing of the charging system. I suspect if you asked them today, they would still deny it, and blame it on the riders' riding style.

The japanese refer to this as "saving face" --- I'm wondering how that translates into German???

[Weasel]

$5 word I can't pronounce!

[RRE70]

Originally Posted by Penguin

Perhaps. But maybe just plain old stubbornness...

For a decade (or more) in the 1970's/early 1980's, BMW used spring-loaded sidestands on their motorcycles. Everyone constantly complained as it is quite difficult to hold the sidestand out with your left foot while gently tilting the bike onto it. BMW's answer was that a proper rider should dismount the motorcycle to the left before putting the sidestand down.

Think about it. Particularly when you are touring and have sidecases and a bunch of stuff strapped onto the rear of the seat.

It was so bad that there were at least 3 companies selling replacement sidestands that bolted onto the frame, were ugly, and costly ($75-150 in 1981 dollars). Yet, they sold a lot of the ugly things, including one to me, because of the bad BMW design.

BROWN Sidestand BMW R100RS,R75/5,R100S,R80RT,R90S,R80/7 - eBay (item 380299314100 end time Jan-13-11 10:49:41 PST)

Finally when they came out with the K series of bikes they stopped using spring--loaded sidestands... it only took a decade for their customers to pound it into the engineers' heads.

In the early 1990's when BMW added power-hungry ABS systems, the bike began having under-charged battery problems. BMW blamed it on the riders taking too many short trips and/or keeping the engine RPMs too low. Sound familiar?

It got to the point that they were giving a free BMW 3 amp battery charger with every new motorcycle (I got one with my 1991 K75S). After 2-3 years of this, they stopped giving away the free battery chargers and no one had any charging problems. Oh, and there was a new, larger alternator attached to the engine when they stopped giving away the free battery chargers.

BMW representatives and presenters at the BMW National rally never, ever admitted there was a problem with the sizing of the charging system. I suspect if you asked them today, they would still deny it, and blame it on the riders' riding style.

Great story, sounds very, very familiar..... Is there any way we can 'prove' the X5 alternator is too small? i.e. can we calculate out 'total' current with all devices running, and do we know the maximum output current of our alternators? I am going to see if I can find this info.

[JCL]

Originally Posted by RRE70

Great story, sounds very, very familiar..... Is there any way we can 'prove' the X5 alternator is too small? i.e. can we calculate out 'total' current with all devices running, and do we know the maximum output current of our alternators? I am going to see if I can find this info.

I don't think the alternator is too small. If it was, then everybody would have a flat battery after starting the car a few times.

The problem is that it doesn't charge often enough and strongly enough, because of a computer program that tells it to disengage or operate with reduced parasitic load, so that the driver can get to 100 km/hr a fraction of a second quicker, or so that the vehicle gets better mileage on a test cycle.

It isn't a peak charge problem, it is an average charge problem.

[RRE70]

Originally Posted by JCL

I don't think the alternator is too small. If it was, then everybody would have a flat battery after starting the car a few times.

The problem is that it doesn't charge often enough and strongly enough, because of a computer program that tells it to disengage or operate with reduced parasitic load, so that the driver can get to 100 km/hr a fraction of a second quicker, or so that the vehicle gets better mileage on a test cycle.

It isn't a peak charge problem, it is an average charge problem.

That depends on 1) how the battery was charged at first 2) how many electrical 'users' are switched on during driving 3) how long the drive is 4) the 'general' state of the battery. Because there are so many variables, the problem is how to pinpoint the exact cause.
If it is the computer telling the alternator not to charge the solution would be relatively easy; a software update (as is done with the switch to AGM-02 batteries). If it was an emission c.q. more power/better mileage, I would think that the engineers in Munich would have had a trick to get better grades when tested (as is often done....), but not let customers get flat batteries.....
By the way; the battery is supposed to get charged to only 80% because of the Efficient Dynamics, rest has to be done by braking. It could also be that exactly this is our problem.... As you said, not charged strongly enough. And as we all know, this will eventually lead to a substantial shortening of the battery lifespan....

[deutsch100]

Originally Posted by Weasel

$5 word I can't pronounce!

Sadly, this is just a direct translation of "Saving face", and not a used saying or word

[AzNMpower32]

Curious, what's the normal voltage of an X5 when the vehicle isn't running and there is a load? I checked the X5's voltage this afternoon with the engine off but all electrics ON; vehicle has not been driven in a couple days: 11.8V.

The battery was just replaced on 23. Dec 2010. One thing I noticed that's new (compared to before flat battery) is that the P is not illuminated/displayed on the gear shifter until I put the key into the dash slot.

[Penguin]

Originally Posted by JCL

It isn't a peak charge problem, it is an average charge problem.

But Alternator output is dependent upon RPM. So you are right, it isn't a peak charge problem, but still may be an undersized alternator problem in that the alternator cannot provide enough output at lower RPM to fully-charge the battery on short trips, e.g., the software may be asking for max charge from the alternator, but the alternator cannot comply due to low RPM. I suspect that there would be no problems with batteries going dead from short trips if people put the transmission in manual mode on short trips and kept the engine RPM's at 4,000, even while stopped at stoplights.

Here's the curve for a couple of alternators, and you can see that at 2000 - 3000 RPM (shaft RPM, not Engine) the output is much less than Max:

http://image.superchevy.com/f/902272...c_alt_03_z.jpg

http://www.vortexbuicks-etc.com/CS144.jpg

I don't have the X5 pulley ratios, so I can't translate alternator output to engine RPM, but the effect is there, it is only a question of to what extent.

To help avoid the battery issue, I tend to put the transmission into Sport mode if I know I am doing short trips.