I have an alternator in my car that I bought new in January. It's always read about 13 volts when driving (RPMs above idle), less with a full electrical load on it (everything on). I thought it was supposed to read at or just above 12 volts with everything on at idle, but mine reads about 10.5. I know the meter is accurate, I've tested it with a voltmeter. Is this normal??? I can still warranty the alternator if I need to, but I don't want to if I can help it. Thanks guys.

 

First off, check the battery with a meter with the car at idle with no accessories on. You should see more than 13v. If lower, there's something wrong.

I would also double-check your battery terminals.

There may not be something wrong with the alternator, you need to make sure the rest of your charging system is healthy - good connections, etc.

Dale

 

What about the condition of your battery?My guess would be that it is getting tired.

 

The battery is an Optima battery, which I installed brand-new at the same time I put the alternator in. To the best of my knowledge it has never caused any problems.

The reason I suspect the alternator is because the previous TWO alternators from the same wholesale supplier had to be warrantied because both times the voltage regulator was bad. The first time it wasn't putting out enough voltage, the second time it put out 16 volts or more, which burned out my high beams (he gladly replaced my headlights - incidental damge). So it seems reasonable to me that the alternator could well need to be replaced again.

As for the battery terminal connections, They seem to be fine... they're screwed on snug enough to where I can't move them by hand. Could that be an issue?

How about that wire that screws onto the rightmost part of the alternator (when viewed from the front of the car)? That's screwed on tight, but could that be an issue also?

What's the voltage supposed to read at idle with a full load?

I do have driving lights and fog lights, 4 lights total, both sets of which have their positive wire attached directly to the car's positive terminal wire. Would that have a detrimental effect?

And what all parts compose an FC's charging system? I think it's just the battery and alternator, but am I wrong?

Thanks guys.

 

1.The fact that the terminals are tight is not enough--you have to be sure there is no oxidation on the terminals.
2.The only way to truly tell the condition of the battery and alternator is to load test them.You should be able to find a shop with the necessary equipment--might cost you $20 to do it.
3.If you have good battery which is charged properly you will see over 13v
4.How tight is your alternator belt?If it is too loose your alternator will not produce maximum current.

 

A fully charged battery without the engine runing and without a top charge is 12.6 volts, 1.2 volts per cell.

 

The belt on my 7 is pretty loose right now, I notice that after you let off the gas or when you step it at any speed, it will fall down for a sec then come back up to about 13v. After I tighten it I'm sure it will put out whats its supposed too, I would start with the simpilist things like that.

 

mine stays anywhere from 13-15 but that is a stock gauge telling me that