Charging problem , please help

[mauro12]

Hi guys , I have a problem with the charging system of the car . I have been having this problem for a few months now but I guess is getting worse . While the car is running at idle , the multimeter shows a charging value of 13.8/14.2v , the values are jumping and are not stable . If I turn on the headlights the charging shows 12.8v ( no charge at all).
The red light on the dash appears only if I turn on the blower fan .
According to your experience , is this a voltage regulator problem or an alternator?
Thank you

[Cees Klumper]

Hi Mauro - sounds like a charging problem, but could also be due to poor/corrosion on battery cable / connections, so I would verify all cable connections and grounds are clean, tightly connected etc. Perhaps this can be checked by measuring Ohm resistance end to end, in addition to visual checks. And are you sure your battery is in good health? Once those things are verified to be good, I would move onto the alternator / voltage regulator. Dashboard charging light should normally not come on, even with lights, fan blower on full, at least it does not on my car.

[mauro12]

The battery has been replaced 3 months ago, varta. I guess is a mix between the alternator and regulator . I was having once some peak of 16v on the multimeter at idle but i've never experienced any bulbs short or problems with the lights in general. I really hope is not the alternator because is quite difficult to find a new version 35amps and quite expensive too. Are there any typical signs of a bad alternator or regulator ? Something that you can distinguish ?

[rwmastel]

Some background on Mauro's issue:  https://www.sl113.org/forums/index.php?topic=37472

[mauro12]

I wasn’t entirely sure about that post . I believe my problem is different that described before . That’s strange , I went down stairs in garage to check one more time and now the voltage is correct but is jumping all around , from 13.7 to even 16v! That’s sounds to me voltage regulator but I’m not an expert . I just bought a beru replacement for 25€ . I will put it and keep updated .
Any reviews with beru regulator ?

[mauro12]

Is there a possibility that a faulty regulator can give the dash red light to come on ?