Battery Life While Parked

[amyracecar]

Originally Posted by 1AddictsAnonymous

My 08 has it, maybe they ditched it for LCI?

Regardless you can pop the latches on rear folding seats, then just lean in from the front, and pull the emergency trunk release inside.

You cannot pop the back seats down from the cabin.. the only manual release is IN the TRUNK..

so don't mess w/ the battery until you fold the seats down or you might not be able to get the trunk lid back open-

[Dackelone]

Originally Posted by Bimmer-Bob

The 12V outlet doesn't receive power when the car is off. That's why you can't use one of those tenders (BMW makes one) that plug in to the cigarette lighter. You have to use the ones with the alligator clips that connect to the posts under the hood.

I use the "BMW Advanced Charging System." I think it's a re-branded Deltran, but it wasn't expensive. Got it from the dealer with a CCA discount.

Originally Posted by methodz

I have a question as I had battery problems with my e90 m3 and don't want a repeat with my 1er. Does key proximity have anything to do with battery drain? I noticed at the car wash that as I walked around with my key in my pocket washing the car I would notice my amber lights kept flashing. My battery actually died at their wash and I had to call a tow truck to jump me. The next day as I was going to get a new battery my car started just fine but I went and got a new battery anyways. I actually didn't expect it to start because it was completely dead the day before. I dunno?

Yes, key fob proximity does effect the car not going to sleep when locked. But in your car wash scenario it just sounds like your car battery was on its way out.

Normally with a sealed cell battery you can drain it(leave your lights or or what ever) once or maybe twice. More than that - your battery will be dead.

With a battery where you can add water to the "cells" you might get a few more total drains on that type of battery. But really IF your battery is older than five years, you are on borrowed time. You should replace the battery - sooner rather than later. Its only going to take one cold morning's cold start to kill the battery for good.

Dackel

[6MT_Addict]

Originally Posted by amyracecar

You cannot pop the back seats down from the cabin.. the only manual release is IN the TRUNK..

so don't mess w/ the battery until you fold the seats down or you might not be able to get the trunk lid back open-

Yes; pop the rear seats before closing the trunk, before disconnecting the battery.

[WP1]

Excellent post! How do you fold the back seat on Convertibles?

My car sits all week (weekend sport car) and no issue so far. The car is a 2010, bought it 2 years ago under CPO until 100K miles.

I was at the dealer this weekend to replace a run flat (thanks god I purchased the tires warranty) and the service guy recommended a battery "thing" to save energy and life on the battery. So, thinking is a battery tenner?

[Vigilante375]

I'm sure it's a battery tender. Everyone uses those for their "only when its nice to drive" cars.

[mr.fabulous]

Some good discussion on this lately. See what happened to one listmember by reading the last few pages of http://www.1addicts.com/forums/showt...673104&page=78. There is also good information at http://www.1addicts.com/forums/showthread.php?t=1101203.

[bmw1racer]

According the BMW service advisor, if you don't lock your doors, the car's electronics are in a low power idle for an extra 10-15 minutes, sucking the life out of your battery (which explains why you can still run the radio even with the fob removed)... That's never mentioned anywhere in the manual.

[ossi1]

Originally Posted by bmw1racer

According the BMW service advisor, if you don't lock your doors, the car's electronics are in a low power idle for an extra 10-15 minutes, sucking the life out of your battery (which explains why you can still run the radio even with the fob removed)... That's never mentioned anywhere in the manual.

thanks, amazes me how simply opening the passenger door when its unlocked primes the fuel pump...I mean why ?

[bmw1racer]

Originally Posted by ossi1

thanks, amazes me how simply opening the passenger door when its unlocked primes the fuel pump...I mean why ?

Sometimes you gotta wonder what's the reasoning behind some these things... Seems like it's complexity for complexity's sake.

I still wonder who OK'd the elimination of the oil dipstick for an electronic one.

[Silenus]

Originally Posted by bmw1racer

Sometimes you gotta wonder what's the reasoning behind some these things... Seems like it's complexity for complexity's sake.

I still wonder who OK'd the elimination of the oil dipstick for an electronic one.

Are you guys serious?



To answer the draw question I did a parasitic draw test on a 128i last week.

Immediately after starting the test: 0.69 amp draw
10 Minutes: 0.46A draw
20 minutes: 0.20A draw
30 minutes: No measurable amperage.


So the E82 does very well as far as going to sleep and putting load on the battery. These cars are WONDERFUL for battery life, but ignorant customers will continue to gripe about having to register their battery.

[bmw1racer]

Originally Posted by Silenus

These cars are WONDERFUL for battery life

Then how do you explain why my battery died in about three years time?

And as I've mentioned in other threads, the E36 that I owned for 18 years only had to have the battery replaced once.

[mr.fabulous]

Originally Posted by Silenus

Are you guys serious?



To answer the draw question I did a parasitic draw test on a 128i last week.

Immediately after starting the test: 0.69 amp draw
10 Minutes: 0.46A draw
20 minutes: 0.20A draw
30 minutes: No measurable amperage.


So the E82 does very well as far as going to sleep and putting load on the battery. These cars are WONDERFUL for battery life, but ignorant customers will continue to gripe about having to register their battery.

Yes, actually... very serious. And quite far from ignorant. My issue is not with the car's power management, but rather with BMW's expectation that I visit my dealer and pay $600 and lose a day of my life for the privilege. I should be able to register a new battery easily and without additional expense (put this on the stalk).

[Stock4Evr]

After having my 2012 135i for 31 months, 17595 mileage and driving it, at least, once a week, at least 100 miles my battery just died one day. The car, when not driven, sat in my garage, unlocked, with no doors, hood, truck open. After much effort was able to get it boost started and took it to the dealer. They replaced the battery and charged me $391.30. I objected to the charge but to no avail. I now keep it on the trickle charger sold by BMW.

I once parked, on blocks, a 325i for a year with the battery cables disconnected. When I returned I connected the battery and it started right up.

[bmw1racer]

Saw this post at the Bimmerfest forum:

You can thank BMW and the EPA for shortened battery life. BMW programmed their "intelligent battery sensor" to disengage the alternator when the battery is less than fully charged. So if you drive several consecutive short trips (with the radio, A/C, and other power hungry conveniences on) your battery will discharge, your clock will reset, and your car may (or may not) have enough juice left to start the car. Disengaging the alternator puts less load on the engine and the car gets more EPA mileage. This in turn helps BMW sell more cars. Unfortunately the people they are selling the cars to might get stranded once in a while. The charging design will also have the effect of shortening the life of the battery.

In their typical fashion, BMW does not alert their drivers to this condition. Nor do they offer an intelligent battery sensor program that will charge the battery to 100% upon request (when the EPA mileage no longer is a sales issue).

EDIT: I just found that BMWNA is in litigation regarding batteries: http://www.law360.com/articles/61014...ated_content=1

[mr.fabulous]

Interesting stuff. How does the alternator disengage? Is there a clutch? I don't believe there is, and the E90-93 Bentley makes very little mention of this (quick perusal)... but they do describe the Intelligent Battery Sensor in some detail (sort of... there is reasonable discussion of what gets measured, but little mention of how that data is used).

Also described in Bentley are items that reset if the battery is removed... but my experience with my car is considerably different (I didn't lose radio, window regulator, compass)... and so perhaps there's been an update since?

http://pdfserver.amlaw.com/nlj/MORAN..._complaint.pdf

[bmw1racer]

Originally Posted by mr.fabulous

Interesting stuff. How does the alternator disengage? Is there a clutch? I don't believe there is, and the E90-93 Bentley makes very little mention of this (quick perusal)... but they do describe the Intelligent Battery Sensor in some detail (sort of... there is reasonable discussion of what gets measured, but little mention of how that data is used).

Also described in Bentley are items that reset if the battery is removed... but my experience with my car is considerably different (I didn't lose radio, window regulator, compass)... and so perhaps there's been an update since?

I reprogrammed my UltraGauge to monitor the battery voltage and when I'm driving the car I'm reading a pretty steady 14 volts, which means the alternator is charging the battery... And I don't see how the alternator gets disengaged.

[mr.fabulous]

Originally Posted by bmw1racer

I reprogrammed my UltraGauge to monitor the battery voltage and when I'm driving the car I'm reading a pretty steady 14 volts, which means the alternator is charging the battery.

Put your charger back on after a week or two and report what you find. I've had my Battery Tender running for three hours as I type this (been two weeks since I last did this), still red (charging).

[bmw1racer]

Originally Posted by mr.fabulous

Put your charger back on after a week or two and report what you find. I've had my Battery Tender running for three hours as I type this (been two weeks since I last did this), still red (charging).

This past week I've attached my CTEK charger every day once I've got home and it takes about 2.5-3 hours to reach 100%.

[str8shot]

Originally Posted by bmw1racer

Saw this post at the Bimmerfest forum:

You can thank BMW and the EPA for shortened battery life. BMW programmed their "intelligent battery sensor" to disengage the alternator when the battery is less than fully charged. So if you drive several consecutive short trips (with the radio, A/C, and other power hungry conveniences on) your battery will discharge, your clock will reset, and your car may (or may not) have enough juice left to start the car. Disengaging the alternator puts less load on the engine and the car gets more EPA mileage. This in turn helps BMW sell more cars. Unfortunately the people they are selling the cars to might get stranded once in a while. The charging design will also have the effect of shortening the life of the battery.

In their typical fashion, BMW does not alert their drivers to this condition. Nor do they offer an intelligent battery sensor program that will charge the battery to 100% upon request (when the EPA mileage no longer is a sales issue).

EDIT: I just found that BMWNA is in litigation regarding batteries: http://www.law360.com/articles/61014...ated_content=1

Clearly they don't understand the system and why the battery is never fully charged. It's also the reason the battery is gigantic. It's sized to give you the same necessary reserve and CCA at 80% charge as a normal sized battery at 100%.

Read the attached PDF. It explains it perfectly.

[bmw1racer]

Originally Posted by str8shot

Clearly they don't understand the system and why the battery is never fully charged. It's also the reason the battery is gigantic. It's sized to give you the same necessary reserve and CCA at 80% charge as a normal sized battery at 100%.

Read the attached PDF. It explains it perfectly.

Thanks for the info.

Where did you find this? Is more info like this available?

[bmw1racer]

Did some Googling and found this:

[mr.fabulous]

Originally Posted by str8shot

Read the attached PDF. It explains it perfectly.

Originally Posted by bmw1racer

Did some Googling and found this:

This is some fascinating shit. Seems a bit Fritz over-engineered? But still fascinating. Skimmed both docs, and the one thing I'm not sure I've read is exactly *how* they unload the alternator (it's not mechanical).