I have a meter. Just didn't have it with me at the time.
Now I just gotta drive to the car, as it's not close to my house.


I might get a battery... as I've owned the car for a around 2 years and I don't think the previous owner had a new battery so I figure it could be close to its end date

If the battery is 14 years old, it owes you nothing at this point.

BMW batteries should have the month and date stamped on top of the positive post as I recall.

I doubt it's 14 years old.. I'll check date.

If my battery was dead wouldn't I not be able to get the doors to unlock or wouldn't the windows and lights on interior not turn on?

Because all interior lights and all are bright and come on. And I can roll windows or unlock doors.

The red battery light is really a Charging System Light, not a light to tell you the battery is dead. You know the battery is dead because it stops working. The charging system runs all electrical circuits after the engine is started, the battery is only used to start the engine. You might sit in a parking lot with the radio on and the engine off, but the design intent of a battery is to start the car.

If the charging system light is on while the engine is running, then you have alternator trouble, or connection trouble of the alternator. Since alternators wear out and connection troubles are seldom spontaneous, my money is on the alternator. Specifically, the brushes that are part of the voltage regulator that can be removed from the back of the alternator. If you know how to take the regulator out, there's a small chance that you can do so without removing the alternator from the car, but I think you will need to take the alternator out to fix this.

In a related note,
My X5 was parked on the street the other day and the alarm sounded for no apparent reason. It stopped after 45-ish seconds, and went to a delayed beep every 10-ish seconds. Oddly, the battery was dead. Sorta. I got the jumper cables out and got the car going, and then put my charger on overnight.

My issue now is that I have the 4x4 symbol lit up. I was going to use my PASoft to clear the fault, but I don't have an XP machine anymore. (I have a machine that runs XP, but the power supply is toast or the main board is toast -- either way it does not turn on without more testing.) My question is, is the light on for no other reason than the battery died?

Interior lights and door locks don't draw much electricity. Turn one the bright lights, fan, radio, leave the door open and try to start the engine. If battery is dead the lights should dim. If you unlock the cluster as mentioned you can read the current amount of voltage in the battery. The best thing to do is have the battery load tested--local auto parts store will do it free. When you jump a vehicle that has a dead battery the cables should be connected for a few minutes before trying to start the vehicle. If battery is good it could be that the battery terminals just need to be cleaned. That's the easy stuff to do.

Update
 

I went to check on the x5..

When turning the heat and headlights it does dim and almost die. But if my alternator is bad and I can't turn the car on wouldn't that kill the battery alone...

Anyways I'm towing to my house instead of shop.

I will buy alternator and I will do it myself, then take the old one to be tested. Or the other way around....

And I may end up buying a battery after that.
That way I don't need to be worried about either.

Will update tomarow after I tow it home.

After the engine starts, the alternator takes over powering the electrical systems. If the alternator fails, then the battery does the work for as long as it can. So, just because the light comes on does not mean the car will die right away. My F150 took about 30 minutes to give up the ghost.

I would try a battery first IMHO. when I first purchased my x5 I noticed battery issues when the temp would drop to -25c and when I try to start the x just click ,click, .I checked the date on the battery which was a bmw battery and at the time it was less than 3 yrs old. replaced battery the following summer and it has been fine ever since. it would start in -45c weather no problem.