- Dec 16, 2007
I had my charging system tested today and it failed, tester read Excessive Ripple. Isnt that basically telling me my alternator is shot?
Back to life...
Your car wants VDC (volts direct current). Alternators produce a small amount of VAC (volts alternating current) that your computers don't like. There is a diode in the alternator that is supposed to suppress the VAC ripple. No more than .4 vac is acceptable. Once it goes above this you will start to have driveability issues.
I found this thread cause I have that problem and I'm looking at rebuilding the alternator instead of replacing it.
Slight correction from an EE. Alternators only create alternating current (AC). The diodes in the alternator rectify the AC to create direct current (DC) needed to power the car and charge the battery. The DC created is not pure and has AC superimposed upon it. The amount of AC on the DC is called the ripple. If one of the windings is bad or if a diode is bad the amount of ripple will be more than normal with the result the effective DC will be low potentially causing malfunction and poor charging of the battery.
Thanks for the insight... I'm still learning...
What causes a diode to go bad?