[MrQuickR1]

I had noticed my angel eyes the other night blinking with the parking lights when I unlocked the doors. Normally it just turns on (welcome lights) and last night it did just that, turned on and stayed on.
so to my curiosity I googled blinking AE's and one thing led to the other.
History: When I bought the car I had a weak battery, local Indy replaced it with Interstate. I have been having so many annoying issues with the car such as making a left turn it bogs down like loss of power than jerks back into power or when starting it makes a clunk/bang sound just as it kicks over, etc...
Dealer replicated it and said it's probably because it's the Interstate battery, nothing to be alarmed about. But I suspect there is still soem underlying issue going on.

So I checked just now before cold starting at the battery in the truck...
12.18v than after a minute went up to 12.37v before starting.
I started it and went back to the trunk and the first number I saw was 11.79v..
at cold start idle and after warm up the idle fluctuated steadily back and forth from 14.16-14.29
Turned on headlights heated seats heat full blast and radio on...14.18-14.63 fluctuating steadily, it never sat on one number just back and forth all different numbers.
Shut down the engine, let it sit a few minutes, it dropped to 12.67 then went up to 12.74

I read about voltage regulator, it gets conflicting, some say its to regulate steady voltage (which is what I believe) and some say the regulator only kicks in if the voltage spikes too high then it will regulate it back in range.

I questioned the alternator a while back, even asked my SA if it would throw a code, he said no, not all the time.
I asked if I should just replace it and he said no its not an easy job to do and it's costly. He advised me to bring it back so they can cold start it but they gave the generic diagnosis of the car " it's the normal characteristic of the vehicle"

Anyone with experience on charging systems, does this sound like the Interstate battery or does it sound like the voltage regulator or alternator altogether? I would rather not spend nearly $500 on an alternator if it really isn't the problem or a problem.
Does this sound normal or should I dig deeper?

Thanks for your time reading this

[cn555ic]

did you install a battery with similar amps? If so you need to register and code in the battery..

[MrQuickR1]

To be honest, i didn't check the old battery to the new Interstate battery that was put in.
The shop told me and is in the receipt that they registered the new battery.
I asked the SA at BMW if it needed to be coded and he said no, only for the black batteries.
I'm still googling this symptom and it is still not a definite resolution. It has my head going to the battery, then the regulator, than the alternator, then to a bad ground on the chassis.
I was hoping maybe someone had a similar issue and can point me to the right direction. I more than likely will not give up until I can can get this narrowed down.
But something in me felt after the battery was replaced, it wasn't done right. I don't know why but I get that feeling.
Maybe because one day I happened to open the battery cover and noticed the battery just laying in there and not strapped down. I had to remove the original anchor and move it up a slot to hold the battery in place. I felt the confidence level drop from the shop I thought was good.

[ctuna]

Try trickle charging the battery.
Then check again.
I have an interstate and have no trouble it has a 95 ah rating . Its just a battery . I don't run my DRL's after 50 years no DRL's they make no sense to
me.
If you are doing a lot of short drives or letting the car sit
you may not be running the car at rpms sufficient to fully charge
the battery.
When these car sit they are consuming battery power especially if you
leave them unlocked and the keyfob nearby.
If I let my car sit for a week it will be down form 12.7 to around 12.3 with the doors locked. The voltage when running is around 14 similar to yours.
There are many threads on people having battery issues with these cars with as little as two years old because of the way
they suck battery power. Its a good idea to have a charger and use it if you don't do some miles on the highway every day or two.

Also I think you should seek another opinion those symtoms don't
sound like a battery to me.

[MrQuickR1]

Originally Posted by ctuna

Try trickle charging the battery.
Then check again.
I have an interstate and have no trouble it has a 95 ah rating . Its just a battery . I don't run my DRL's after 50 years no DRL's they make no sense to
me.
If you are doing a lot of short drives or letting the car sit
you may not be running the car at rpms sufficient to fully charge
the battery.
When these car sit they are consuming battery power especially if you
leave them unlocked and the keyfob nearby.
If I let my car sit for a week it will be down form 12.7 to around 12.3 with the doors locked. The voltage when running is around 14 similar to yours.
There are many threads on people having battery issues with these cars with as little as two years old because of the way
they suck battery power. Its a good idea to have a charger and use it if you don't do some miles on the highway every day or two.

Also I think you should seek another opinion those symtoms don't
sound like a battery to me.

I didn't think these symptoms were a battery either, and I'll take that advice. I just needed to hear it that it isn't "normal" as far as the symptoms.

I drive the car ~80 miles round trip to work daily and mostly highway at speeds around 60-85 1/2 of the time driving so I think that should be enough to keep the battery juiced.
Also have the BMS pbx in there but I don't even use it because it makes my symptoms much more amplified such as the jerkiness and erratic shifting. Even though the car had been updated/re programmed, it was good for 2 days and went back to crap again. I had in my mind maybe the pbx is defected or is sending out screwed up signals?

With the AE's blinking the other night, the doors were locked and the fob nowhere near it, although that is excellent advice. I notice when I wash the car, the door handles get wet and the doors lock and go wacky cause the fob is on my belt loop.
So the alt is charging, but is the fluctuating voltage normal? It's bouncing all over and that kind of threw me a little. Other than that, could the battery have a weak cell? I know I had sears batteries and put one in my daughters car to only go bad within a year. It does happen, just hard to believe sometimes.

[acediac]

I took my voltage regulator out recently to troubleshoot a problem, and thought these pics may help. It's easy to get to without having to remove the alternator, just have to remove the top cowl which has the cabin air filter, front airduct, and the airbox with engine air filter. You can then access the alternator from behind and unscrew the plastic shield with 3 bolts.

The voltage regulator itself has 4 bolts, 2 long, 2 short, make sure you note where they go! (I BELIEVE, from memory, the long ones were the bottom two, but don't trust me on that)

The voltage regulator has 2 spring loaded bushes that tension against that middle round drum on the alternator, be careful when removing it from the alternator.

1st pic: the plastic shield at the back of alternator, held on by three bolts
2nd pic: voltage regulator, side that faces to the back of the car (note the cooling fins)
3rd pic: voltage regulator, inner side that faces the alternator
4th pic: Back of alternator, shield removed, voltage regulator still in place (you can see the 4 bolts holding it in)