Omega Owners Forum

Omega Help Area => Omega Electrical and Audio Help => Topic started by: valliant72 on 11 June 2011, 19:41:35

Title: Possible Alternator failing
Post by: valliant72 on 11 June 2011, 19:41:35

Had the battery go flat yesterday, checked nothing had been left on which there wasnt. Car had been on a 15 miles journey previously so battery should have been fully charged. Recharged the battery and did the test as shown on the forum, battery was around 12.8 volts on its own. Connected to the car was around 12.7 turned a few things on for a few mintures then off battery recovered to around 12.7. Started the car, on idle alternator giving out about 13.7 then under load revs  2000 rpm around 13.9. Checked for any drains on the battery got 0.03 ma so seems nothing is draining. All connection are secure and clean. I have noticed sometimes on occasion its turns over a lil slower and the dash lights seem to have a pulsating about them. Im wondering if when the engine gets hot the alternator is failing intermittantly.

Title: Re: Possible Alternator failing
Post by: Andy H on 11 June 2011, 19:58:30

Have you checked the condition of the earth strap and battery connections?

Quite common for the crimped battery connections to break up and cause odd charging and starting problems.

Have a read of this guide Battery charging and starting diagnosis (http://www.omegaowners.com/forum/YaBB.pl?num=1225724099)

Title: Re: Possible Alternator failing
Post by: valliant72 on 11 June 2011, 20:35:56

yep check all earths all clean and secure, the battery crimps are good no corrosions. yep i went through the battery and starting diagnosis. Only other thing i have noticed is a rattle on acceleration. thinking maybe possible bearing going in the alternator, only happens when the car gets hot. The alternator will give out 13.9 volts max under load from 2000 rpm or above, at idle only 13.7. This did happen before last year after the car had been on a run. Breakdown assistance got the car started but the alternator light was on almost constantly. changed battery and has been working since but have noticed that the battery was mostly only having around a 12.4 v charge. Seems odd 2 batteries with the same result.

Title: Re: Possible Alternator failing
Post by: Kevin Wood on 12 June 2011, 11:28:32

The charging voltages you measured are a little lower than typical but not low enough to cause a problem, IMHO.

Might be worth pulling the alternator out and checking the bearings and also the condition of the brushes and the B+ cable connection at the alternator.

I have a feeling there is a connection inside the alternator between the body and the regulator pack that can corrode. Might be worth cleaning it up?

The crimp where the battery terminal meets the cable from the starter/alternator commonly works loose.