Alternator concerns

[Rubce]

Hi All

Something odd going on with the Stag's alternator today. During a run to Sleap Airfield the voltmeter was showing between 11 and 13volts. Tonight as I reversed the car (no headlights etc on) into the garage in the dark I noticed that the ignition warning lamp was very dimly lit. The ignition light was brightly lit prior to starting the engine as per normal. The alternator is 5 years old, uprated version as supplied by EJ Wards. Any suggestions?

Regards

Bruce

[Phil S]

could be the alternator packing up, but could also be worth getting a drop tester on the battery as the start of cooler weather always sorts the duff batteries out

[Rubce]

With the engine running at both idle and revving it's reading 14.17 volts out of the rear of the alternator

The voltmeter sometime shows under 12 and on other occasions when I start the engine it shows 12.5 to 13

Confused!

Regards

Bruce

[StagJonno]

14+V normally shows a fairly full battery when it's on charge. The alternator is regulated to this sort of figure. However, you could still have a dodgy battery. After a good run or a few hours on a battery charger, leave it to rest (ie no charge and no load) for at least 1/2hr. Using your separate meter, measure the battery voltage. A fully charged battery should give a voltage of 12.6 - 12.7V. If you still experience problems, best next step would be to get a garage to test it for you - the simplest test is a "drop-test", though nowadays more garages seem to have more sophisticated gear which will produce a printout giving a more detailed analysis, including cranking amps.

Presumably "the voltmeter" you mention in your second para is the one in the dash - these are not the most accurate and, as they use an internal heating element with bimetallic strip, they are slow to reach a steady value.

Jonno

[Seaking]

Bruce exactly the symptoms I had turned out to be the brushed had separated . The carbon and wire had parted image_37008 (1).jpg Cheers Glenn

[Rubce]

Evening All

When I said it was reading 14.17v out of the rear of the alternator I actually meant at the point where the cable emerges on the other side of the engine bay. Since then I pulled the top off the plug in the rear and found the alternator was chucking out between 4 and 14.17v. Hmmmm!

Regards

Bruce

[Rubce]

Yes Jonno, I was referring to the voltmeter in the dash

Regards

Bruce

[Rubce]

Hi Glenn

I think I will be fitting my spare alternator and then taking the existing one apart. I wonder if I will find the same problem as in your photo.

Regards

Bruce