2001 BMW X5 5MT charging issue.

[chedeng]

Hello All.

I bought this X5 March 2017 and one thing stumping me is the charging system (which I need help on). This vehicle is driven 90 miles/day so it gets plenty of 'charging' time.

Timeline:

March 2017: - When I got the car, the voltage across the battery was >16Volts when running . . . can't be good for the electronics.

• I changed the voltage regulator (Bosch).
• Put in a brand new battery. Measured voltage went down from 16V to 13.2 Volts (running) and not much more which is odd.

April 2017 - Drove the car like this for a month and noticed that my battery light on the cluster started blinking. I checked the voltage on the cluster while driving with a voltage of 11.2 volts.

• Replaced alternator with a brand new Bosch AL0703N. No change in the voltage still reading 13.2V across the battery (running).
• I put in a different battery from my other car but issue remains. Re-installed new battery.

May 2017 thru Present - I have been driving this car all these time and have never seen the battery light flash until yesterday.

Note: I am working on getting a replacement alternator. I will be returning the new alternator and see if I can get a replacement.

Here are my questions:

1. Could this be a grounding issue?
2. Where are the ground straps located on the vehicle that I can check for cuts/corrosion?

Thanks

[chedeng]

Update: I replaced the new Bosch AL0703N with Duralast Gold alternator and now getting close to 14V @ idle and about 13.5V with all accessories ON. I got already an RMA to return the Bosch alternator. This shows that 'new' does not guarantee that it will work 100%.

Duralast Gold is brand new and have the lifetime warranty as long as I own the car. I did the whole swap in 1.5 hrs. I am hoping this issue with the charging system will be resolved permanently.

[chedeng]

Hi,

All is not well with the X5. Even with the new alternator (mind you a lot better with the old one), it is still very low 13.5V. I did more investigating and started checking for voltage drops. Ground side is good (0.1V) but the positive side is 0.95V.

The starter stud where the two positive cables meet (from B+ and alternator) is getting hot. I can remove the 13mm nut from the back of the starter from underneath the car by removing the stiffening plate.

Already placed the order for the two cables and should arrive next week. It looks like the starter stud has not shown any melting plastics or anything. At least that's what I am hoping for since it will be a b**ch to get to the starter.

My plan is to "fish" the new cables using the old ones and hopefully hitting no snags along the way. I will keep you posted.

[80stech]

It's very unlikely that you need to replace the cables. Usually just connections are corroded.

[chedeng]

I was tracking my order and found that they are back ordered and will not be getting them on time. I will inspect both cables and see their conditions. I will also check the terminal post on the back of the starter but it is hard to see. I normally use my iphone to take pictures of blind locations with the Bluetooth clicker. (That clicker came with my selfie stick bought from Asia). I knew that stick will have a use.

[chedeng]

It’s a success. I pulled both cables out. Cables looked good but made it better by taping them up. Cleaned all terminals. Getting full 14.2volts now. Voltage drop on the positive side is close to 0V.

[oldskewel]

Originally Posted by chedeng

It’s a success. I pulled both cables out. Cables looked good but made it better by taping them up. Cleaned all terminals. Getting full 14.2volts now. Voltage drop on the positive side is close to 0V.

Trying to figure out what the problem was...

I can see that "taping" might prevent future problems, but not likely to fix anything now.

Was it that the connections needed to be tightened?

Or that the connector surfaces were corroded and needed to be cleaned?

Or something else?

Also, when you get 14.2V, is that with a voltmeter across the charging posts in the engine bay, or something else? Did you also check it from the cluster test (that in my experience reads a fraction of a Volt lower than at the charging posts)?

[80stech]

How much work was it to get to the starter connections ?

[chedeng]

Undoing the 13mm nut from the starter took 20 minutes. I could see the starter from underneath but could only put one arm at a time to get to it and have to do it blind too. I used a 1/4" drive ratchet / 13mm socket to loosen the nut with every three clicks on the ratchet since there's not much room. Dropped the ratchet many times and have to place it back on the nut, very frustrating (cursed many times too).

The prep time took the most.

• Put the car on 4 ramps
• Removed the positive cable from B+ only. (not from battery)
• Removed the air box and ducts to get to the alternator nut
• Removed 13mm nut from back of alternator
• Removed the bottom stiffening plate six(6) 16mm nuts
• then do above to remove starter 13mm nut

Note: I tied strings on the each cable's eyelets (alternator side and B+ side) before removing both cables to help "fish" it back. Total of 4 hrs from start to finish.

Also cancelled the order for the two cables.

[StephenVA]

Thanks for the follow up on the process and the solution. Glad to read all is normal now.