Possible Alternator issue - low voltage

Oskar

Oskar

A2OC Donor
Hi all

Just looking for some comments from others experience. I have a 1.4 AUA 2001.

My battery has stopped charging in the car, after being laid up for 2 weeks.

I have externally charged the battery overnight, but after some driving, the battery warning comes up, and then the power steering goes etc, and I limp home.

I am thinking the alternator (even though it is an APD refurbished one with only 4 months use), as the exit voltage at the alternator at idle is 9.65v.

Should it be over 12v at idle? (I am assuming yes, up to just over 14v???).
Is there anything else to look for (I will take the alternator off later, and look at the clutch etc, but it all sounds normal, and the belt is new etc).

The only other thing I have changed around the same time is the coilpack, to a new Bosch one. The motor runs well, and there are no faults on VCDS, so unlikley to be the cause, unless it is leaking a lot of volts! I am tempted to put the old one back on.....

Also, can I check the alternator/charging on VCDS, and if so, please let me know where I would find this. There are no obvious faults in this area I can find, but a lot of consequential ones!!!!

Thanks

Matt
 
When connected to the battery, and engine idling, voltage should be at least 13.8 Volts.
If your battery measures at least 13 volts, of the car, and on the charger, then the alternator is likely duff.
Mac
 
You can check and record/graph the voltage using any OBD2 plug, I used Torque to collect the data on my phone and exported it to Excel - that was how I identified the valtage regulator in my alternator was faulty.
 
I would check the ground cables and the connectors/terminals of the alternator first. You don't need further vcds or torque research. Your voltage is way to low, either a connection Problem or the new alternator has a Mailfunction.
 
An update (result) here.

I took the battery out for a damn good charging, and when reinstalled, all was well. Alternator showed about 13v or more, and battery has lasted after a good run (where it was just draining).

I think it was the positive terminal. The negative gets a lot of attention as this is what I disconnect when fixing stuff up front, but had never taken off the positive. It may have been the sitting in the cold. I did not own the car last winter.

Thus, as we all know with the A2, the battery is very important in regards to having the correct model, in good condition, and ALL connections maintained and tight.

I already have an additional earth off the engine head, and had cleaned and tightened the main earth, as I changed the starter motor a few months ago.

I would expect the alternator was showing a low voltage as that was all it could feed into the battery, due to the poor positive connection. That is my assumption, but perhaps voltage does not work in that manner……

All good as of this morning. Let’s hope it is all still good tomorrow!

Thanks for the feedback

Matt
 
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