Bad Alternator?

[siny528i]

Heya guys,

I have had problems with my Bosch battery (mfd Dec 2013) for a few months now.
Mostly its being dead on cold days.

So today in the morning I replaced it with DieHard (mfd Jan 2019) and it was Ok in the beginning.
Car started nice. Reading for battery showed ~12.6V before start and ~14V when running.

Then after driving it for couple hours BATTERY light came on and it lost power.
Then again Ok for some time. Then again Bad.

When the BATTERY light was on AND car was running it read slightly over 12V.
Do you think I need a NEW Alternator?

Thank you in advance,
siny528i

[sienayr]

Head to your nearest auto parts store, they will be able to test the system for free and let you know where the problems are.

[siny528i]

Head to your nearest auto parts store, they will be able to test the system for free and let you know where the problems are.

Thanks man! I will!

[crazy4trains]

Battery needs to be at full charge before it can be tested. Be sure to do that first. Sounds like your alternator is on the way out.

[JimLev]

Are you sure the battery clamps are tight?
Have you had time to get it tested yet?

[cnn]

With your car at this mileage, chances your alternator brushes are worn.

Best is to google Bosch AL0703N ("N" is new, avoid local auto parts store alternator).
FCPEuro has the Bosch AL0703N for about $210 with LT warranty.

This is the best bang for the bucks.

[siny528i]

With your car at this mileage, chances your alternator brushes are worn.

Best is to google Bosch AL0703N ("N" is new, avoid local auto parts store alternator).
FCPEuro has the Bosch AL0703N for about $210 with LT warranty.

This is the best bang for the bucks.

Thanks cnn!

Let me test it first tomorrow. Then I will let you know!

[Chedley]

Your alternator is going kaput.
Your old and new batteries are probably fine, though they may need recharging.

[amancuso]

I would agree that the alternator is probably failing. How many miles on your 528i? Off topic, but have you come to any of the Tri-State 5ers meets?

[djb2]

Avoid the parts shotgun.

Simply measuring the output voltage won't tell you if the brush is only intermittently making contact.

It's a bit of a PITA, but remove the voltage regulator and measure the brush length. If it's less than 5mm, that's your problem. If your alternator is in good physical condition, buy a replacement regulator. If it's corroded, replace the whole unit.

Notes: Some regulators are held in place by PZ2 head screws, while the surrounding screws are regulator #2 phillips head. The battery cable nut takes much less torque than you expect.

[fedisrico]

Most likely the alternator, I'd replace it before you get the holy trinity of warning symbols while driving

[siny528i]

Heya guys,

Autozone refused to test my Alternator/Battery because my Battery is in the Trunk...
They said its against their Policy.They were the closest...

I was running on "fumes" with BATTERY light on and reading below 12V.
Went straight back to home and ordered new Alternator from FCPEuro.
Gonna change Alternator and keep you posted...

TIA
siny528i

PS. I am at 232k plus. No meets yet

[crazy4trains]

I call BS. Autozone has tested my battery multiple times. Ask them to see the policy.

Make sure your battery is charged. Their equipment can't test the charging system if the battery isn't fully charged. If the battery won't take a charge, well there you go.

- - - Updated - - -

If you are going to own this car for any period of time you need to buy a digital multimeter. If you have a Harbor Freight close they have them for cheap. Any of the big box stores also have them. It won't tell you everything but can help you answer a few questions. Buy one and at least learn the basics of how to use it. I'm electrically stooopid but use my meter frequently.

[siny528i]

I call BS. Autozone has tested my battery multiple times. Ask them to see the policy.

Make sure your battery is charged. Their equipment can't test the charging system if the battery isn't fully charged. If the battery won't take a charge, well there you go.

- - - Updated - - -

If you are going to own this car for any period of time you need to buy a digital multimeter. If you have a Harbor Freight close they have them for cheap. Any of the big box stores also have them. It won't tell you everything but can help you answer a few questions. Buy one and at least learn the basics of how to use it. I'm electrically stooopid but use my meter frequently.

Hey crazy4trains,
You're loosing me, bro... Have you read the entire thread?

My battery was charged... I does not take charge anymore... I was running on "fumes" with BATTERY light on... Readings below 12V... Car is at 232k... 114k (or 11.5 years) of which is on me... Original Alternator that most likely going kaput...

[Ed CT]

Yeah, based on all you posted, you're past needing a battery charging check. Obviously the alternator is not charging the battery. My battery light started to come on faintly & intermittently about 20k miles back. I bought a new regulator and that fixed the issue before I started to have real issues with dead batteries. The old reg brushes were worn to the point that the springs couldn't put enough pressure on them.

And, Congrats on being at 232k miles, siny528. I'm just over 216k miles and the car still runs great.

[siny528i]

Yeah, based on all you posted, you're past needing a battery charging check. Obviously the alternator is not charging the battery. My battery light started to come on faintly & intermittently about 20k miles back. I bought a new regulator and that fixed the issue before I started to have real issues with dead batteries. The old reg brushes were worn to the point that the springs couldn't put enough pressure on them.

And, Congrats on being at 232k miles, siny528. I'm just over 216k miles and the car still runs great.

Thanks Ed CT!
I just can not get rid of it

[crazy4trains]

Hey crazy4trains,
You're loosing me, bro... Have you read the entire thread?

My battery was charged... I does not take charge anymore... I was running on "fumes" with BATTERY light on... Readings below 12V... Car is at 232k... 114k (or 11.5 years) of which is on me... Original Alternator that most likely going kaput...

Yep, read it all. Didn't see anything that indicated you charged the battery.

My BS comment wasn't toward you, but directed to AutoZonedOut.

[siny528i]

Yep, read it all. Didn't see anything that indicated you charged the battery.

My BS comment wasn't toward you, but directed to AutoZonedOut.

I know, bro. They did BS me.
But I've read the battery with DV and posted readings above... at the beginning of the thread

[StephenVA]

The only test that will provide results that can be trusted are the following:
1. At idle what is the voltage at the battery with ALL accessories turned off?
2. 1500 RPM
2: 2500 RPM
testing is done after cleaning the battery posts, cleaning and cleaning and tightening the main jump point under the hood, and doing a volt drop test at the battery and back to the alternator. Remove and clean the main positive cable at the alternator.
The follow up test is to load the charging system with 150 amp draw and rest at the three RPMs as most failures that give off fluctuations (11v to 15.5v) will really go nuts when loaded. A VAT tester is best, but with all the accessories turned on will get you close.

As everyone has mentioned, the brushes wear out overtime and no longer have spring pressure to hold them in constant contact, hence the jump in voltage/no voltage (charge/No charge). At 100K they are on their last leg. Replace with new best bet. DIY is a great way to save $$. Replacing the brushes is well documented here on the forum.

[siny528i]

Heya guys,

Thanks a lot for all of your replies
All is good now!

I've replaced it about a week ago!
Feel terrible couldn't let you know erlier...

It wasn't that hard. I would say 4 out 10.

I never end to wonder how smart and simple this car designed...

Changed A/C (short) belt while was there...

The only concern is that on the back the rubber insulating cover from existing Alternator didn't fit new one 100%.
I hope its not big deal...

Thanks again,
siny528i