New Alternator but still no charge.

[Maysik]

Hi everyone.

A few weeks ago I replaced the battery as it had ran its race.

As the alternator was sus I changed that also as the ALT light was on most of the time when idling and at start up but went off after driving for a while.

This was the same as when I hooked up my new alternator, same symptoms.

I had some electrical work done on the van and I was told my new alternator was not charging the battery. Tested on the car. I removed it and the place of purchase tested it and state that it is charging fine. When I get it back I will be taking it to a third party for a bench test.

In the mean time I have put my old alternator back on and the ALT lights come on as they used to and the same as when the new alternator went in.

Not totally out of the question but both old and new alternators dodgy, possible, but don't think so.

Is there something else I should be looking at here possibly in the wiring or elsewhere?

The new alternator is a 100 amp single wire, internal regulator.

Thanks

Maysik.

[agr071]

Does the Alt light come on when ignition is on? (Not running)

[Maysik]

Hi Agro,

Yes, turn the ignition on before starting car, the ALT light is on. Started engine then ALT light went out.

Idling for about 30-40 seconds the ALT light flashed on very brightly once for a second then went out again.

[agr071]

OK.

a) Check belt tension.(WITH THE MOTOR OFF), You should be just able to move the fan on the alternator by hand.
b) Make sure that the battery supply from the alt to the battery is good and clean
c) Check the earth to the motor

You see, what happens is, when the alternator charges, it sends 12v to the alternator light to extinguish it. Even though there is 12v from the ignition to the other side of the light

If this doesn't work, post a pic of the alternator in it's position and how it's wired, and i'll see if I can help.

[Maysik]

Thanks Agro.

I'll go and do what you said.

[agr071]

O.K.

[maxsandman]

some alternators wont operate at idle, but with a few revs the red light goes out. The higher the output (of the alternator) the more likely this happens. I have several cars that the light is on at idle, but still charge when driven. If this is the case, Im sure it is no worry, but if you change the pulley you may make it better, probably a smaller pulley to make the alternator spin faster.
Just a suggestion only, speak to your supplier first

cheers
Max

[Maysik]

some alternators wont operate at idle, but with a few revs the red light goes out. The higher the output (of the alternator) the more likely this happens. I have several cars that the light is on at idle, but still charge when driven. If this is the case, Im sure it is no worry, but if you change the pulley you may make it better, probably a smaller pulley to make the alternator spin faster.
Just a suggestion only, speak to your supplier first

cheers
Max

Thank you for the input, what you suggested first sentence, does happen.

I will look into it.

Maysik

[agr071]

some alternators wont operate at idle, but with a few revs the red light goes out. The higher the output (of the alternator) the more likely this happens. I have several cars that the light is on at idle, but still charge when driven. If this is the case, Im sure it is no worry, but if you change the pulley you may make it better, probably a smaller pulley to make the alternator spin faster.
Just a suggestion only, speak to your supplier first

cheers
Max

Maysik said that it happened with the new alt as well,which would rule this out.

[agr071]

How did you end up with this Maysik?????