Issue with charging system

[ajagostini]

Recently, my e90 gave me a “low battery voltage” warning...thinking that a spirited-highway drive might have helped, i went on a drive and 16 miles later all kinds of warning lights started to come on until the engine quite at 80mph down the highway. Thought it was the battery, so i replaced it with a pep boys one. Did not drive the car for a week; when i decided to go get a hair cut, the car decided to do it again. I gave the old battery a good charge on a trickle charger and placed it on the car. All systems (settings menu) check “OK” but i still have a message “increased battery discharge”. Does this mean that my charging system took a dump on me?!

[EJT86]

Something might be draining your battery. One common issue is if you’ve got EDC. The module stays on even when the car is off and drains the battery. If that’s the case you’d need to replace whichever EDC modules are doing this. Reason I don’t think it’s your alternator is you said you swapped for a new battery didn’t drive it and it still said low voltage. You could try charging the new battery, it’s not impossible the new battery was nearly drained when it was sold

[pbonsalb]

Car should not die once running if alternator is good since it will provide power to run everything even if battery is no good.

Check your grounds. There are 2 under the motor on the sides. Bad grounds can screw up all sorts of things.

[kyrix1st]

Originally Posted by pbonsalb

Car should not die once running if alternator is good since it will provide power to run everything even if battery is no good.

Check your grounds. There are 2 under the motor on the sides. Bad grounds can screw up all sorts of things.

Would you care to point out exactly where? I think I have a battery leak...

[ajagostini]

started the car this morning, all systems checked “OK”, si I decided to get some errands done. Three hours later...car won't start; increased battery discharge annunciation displayed, then low battery charge...WTF!!!! i had put the Carly reader and showed the battery/charging parameters good (shortly after I installed the completely charged battery) I’m guessing, I might as well take it in the a**, and take the car to the dealer and have it checkedit’s embarrassing to be seen in a flat bed with my freaking M3 on it for the third time in a month!!

[ItsGary]

Originally Posted by ajagostini

started the car this morning, all systems checked “OK”, si I decided to get some errands done. Three hours later...car won't start; increased battery discharge annunciation displayed, then low battery charge...WTF!!!! i had put the Carly reader and showed the battery/charging parameters good (shortly after I installed the completely charged battery) I’m guessing, I might as well take it in the a**, and take the car to the dealer and have it checkedit’s embarrassing to be seen in a flat bed with my freaking M3 on it for the third time in a month!!

If you need a new alternator, RockAuto has the OEM Equiv which is by VALEO for $230USD, I just replaced mine too cause it wasn't charging properly anymore.

[ajagostini]

I just had it towed to Lone Star Bavarian (BMW Dealer/Service Center) I should find out tomorrow what it is...I didn’t think of Rock Auto for foreign cars! i’ll Let you guys know how it went. Fingers crossed!

[ItsGary]

Originally Posted by ajagostini

I just had it towed to Lone Star Bavarian (BMW Dealer/Service Center) I should find out tomorrow what it is...I didn’t think of Rock Auto for foreign cars! i’ll Let you guys know how it went. Fingers crossed!

VAL-439675 is the part number

https://www.rockauto.com/en/parts/va...generator,2412

[ajagostini]

Originally Posted by ItsGary

VAL-439675 is the part number

https://www.rockauto.com/en/parts/va...generator,2412

Thanks for the part number and site!

[chrisymarr]

Same happend me when I replaced my battery.

Did you register the new battery to the car?

I replaced my battery with an identical new BMW one. Everytime I started the car I got increased battery discharge and the clock reset.

Registered the battery to the car and it hasn't done it since.

The car needs to be told it has a new battery so it may think it still has the old bad one installed which is the reasoning for the errors.

[MachinesWithSouls]

So important to remember that the car only charges the battery when coasting and your foot is off the gas. Sitting idle won't help it.

Regardless of what the issue is here, get a tender and hook it up - the amount of electronics these cars have now really strains the system and keeping the battery topped off will help a great deal. I'm still on my original battery and it's 9 years old.

[amrazM]

Let the car go to sleep and leave the trunk open and then come back and check the voltage with a voltmeter and see if there is draw.

[Helmsman]

Originally Posted by SoManyBlueCars

So important to remember that the car only charges the battery when coasting and your foot is off the gas. Sitting idle won't help it.

Regardless of what the issue is here, get a tender and hook it up - the amount of electronics these cars have now really strains the system and keeping the battery topped off will help a great deal. I'm still on my original battery and it's 9 years old.

No offence mate but I don't believe this is quite true. Can't really see why the alternator wouldn't charge when throttle is applied (which is most of the time right..:-). Also its easy to measure healthy current output from the alternator with for instance Carly.

[MachinesWithSouls]

Originally Posted by Helmsman

No offence mate but I don't believe this is quite true. Can't really see why the alternator wouldn't charge when throttle is applied (which is most of the time right..:-). Also its easy to measure healthy current output from the alternator with for instance Carly.

Look it up if you don't believe me. BMW implements a system called Efficient Dynamics on modern cars, and the idea is to only charge the battery under coasting. When the engine is under load, the battery isn't being charged to ensure full engine power is available.

Modern BMWs have a digital gauge on the dash that will light up blue with a battery icon when you take your foot off the gas. The M3 does not have this gauge obviously, but the system is still there.

[Makaveli7]

Originally Posted by SoManyBlueCars

Look it up if you don't believe me. BMW implements a system called Efficient Dynamics on modern cars, and the idea is to only charge the battery under coasting. When the engine is under load, the battery isn't being charged to ensure full engine power is available.

Modern BMWs have a digital gauge on the dash that will light up blue with a battery icon when you take your foot off the gas. The M3 does not have this gauge obviously, but the system is still there.

Efficient Dynamics is great and helps getting that extra hp when needed on the newer bmws (I think its an F dedicated thing and isn't available on the Eseries)

The main reason for registering the battery is for the alternator to reset the charging pattern based on the battery installed.

The alternator varies the charging pattern based on the age and power output of the battery and when you re-register the new battery you are basically resetting this pattern for the optimal charging of the specific battery.

[Makaveli7]

Originally Posted by ajagostini

Recently, my e90 gave me a “low battery voltage” warning...thinking that a spirited-highway drive might have helped, i went on a drive and 16 miles later all kinds of warning lights started to come on until the engine quite at 80mph down the highway. Thought it was the battery, so i replaced it with a pep boys one. Did not drive the car for a week; when i decided to go get a hair cut, the car decided to do it again. I gave the old battery a good charge on a trickle charger and placed it on the car. All systems (settings menu) check “OK” but i still have a message “increased battery discharge”. Does this mean that my charging system took a dump on me?!

This is the normal behaviour when the alternator is dying - The wipers even goes on and off randomly and stop mid way usually. If you had a good battery recently changed, ask for them to charge it overnight and reuse it and save a couple of bucks.

Good luck!

[MachinesWithSouls]

Originally Posted by Makaveli7

Efficient Dynamics is great and helps getting that extra hp when needed on the newer bmws (I think its an F dedicated thing and isn't available on the Eseries)

The main reason for registering the battery is for the alternator to reset the charging pattern based on the battery installed.

The alternator varies the charging pattern based on the age and power output of the battery and when you re-register the new battery you are basically resetting this pattern for the optimal charging of the specific battery.

It is on the E90 platform.

[Makaveli7]

Originally Posted by SoManyBlueCars

It is on the E90 platform.

Oh nice! didnt know it came on the e90s

[Helmsman]

Originally Posted by SoManyBlueCars

Look it up if you don't believe me. BMW implements a system called Efficient Dynamics on modern cars, and the idea is to only charge the battery under coasting. When the engine is under load, the battery isn't being charged to ensure full engine power is available.

Modern BMWs have a digital gauge on the dash that will light up blue with a battery icon when you take your foot off the gas. The M3 does not have this gauge obviously, but the system is still there.

No need to look it up bro. Quick measure with a voltage meter let you know there is higher voltage over the battery than the battery poles, hence charging. And again interesting in the amps details, Carly provide alt current output. The "efficient dynamics" might regulate this a tad but Im guessing more mktg bs. Imagen you where waiting for your wife shopping, listening full volume heavy metal while idling. The battery would dy before she's done...😉

[MachinesWithSouls]

Originally Posted by Helmsman

No need to look it up bro. Quick measure with a voltage meter let you know there is higher voltage over the battery than the battery poles, hence charging. And again interesting in the amps details, Carly provide alt current output. The "efficient dynamics" might regulate this a tad but Im guessing more mktg bs. Imagen you where waiting for your wife shopping, listening full volume heavy metal while idling. The battery would dy before she's done...😉

That's exactly what's happened to me, and why I got a trickle charger. N63s had it so bad that BMW had to replace batteries at 10k intervals for some owners, because they weren't being driven fast enough to coast and charge the batteries.

We see it so many times on the forums here with battery issues - I always say to keep the car on a charger and see if that solves it before chasing electrical gremlins through the car.

[Helmsman]

Originally Posted by SoManyBlueCars

That's exactly what's happened to me, and why I got a trickle charger. N63s had it so bad that BMW had to replace batteries at 10k intervals for some owners, because they weren't being driven fast enough to coast and charge the batteries.

We see it so many times on the forums here with battery issues - I always say to keep the car on a charger and see if that solves it before chasing electrical gremlins through the car.

Still dont quite understand where the energy savings would come from. Assuming it only would charge when coasting it would need to compensate for the energy lost during throttle. Now using the alternator to help with the braking is another thing as that provides energy from "halting the mass". Anyways, as you say keeping the battery well charged prolong its life for sure.

Cheers

[MachinesWithSouls]

Originally Posted by Helmsman

Still dont quite understand where the energy savings would come from. Assuming it only would charge when coasting it would need to compensate for the energy lost during throttle. Now using the alternator to help with the braking is another thing as that provides energy from "halting the mass". Anyways, as you say keeping the battery well charged prolong its life for sure.

Cheers

https://www.autobytel.com/car-owners...ration-123423/

Basically, when the car coasts, the battery gets juice. During acceleration, the alternator is uncoupled.