Alternator - fluctuating voltage

[ozzie]

I posted a message 1 month ago about fluctuating voltage - the reply to which was the earths. Since I have cleaned all 3 (behind the radiator, wheel arch and transmission tunnel). However, the voltage is still fluctuating. My question is now...

How is the voltage/charging of the battery regulated, is it:

a)The circuit on the alternator,
b)ECU,
c)a relay of some kind,
or d) something else!

Thanks for your help, Anthony.

[GreenV8S]

Charging is controlled by the alternator. But depending where you are measuring the voltage, you may be seeing effects from other sources. For example the built-in voltmeter is wired in to the dashboard supply and will be affected by loads on the same circuit. If you're measuring the battery directly you can rule this out, of course,

[IPAddis]

How much does it alternate by?

It could be the voltage regulator on the alternator (mine went) but I still get a variation between 14 and 15 volts on the gauge when running. A multimeter measured the gauge as 1/2 a volt out.

Ian A.

[ozzie]

Between 1/2 to 1 volt variation - can be seen (and heard) in the headlights, dashboard light and the dashboard fans. Also noticeable under acceleration. The frequency is about twice a second.
I was thinking about getting a new/reconditioned alternator- what is the cost of this? and is it absolutely necessary, i.e. it is something I can do myself?

Thanks for your help - I've had this now for about a year!

Anthony.

[IPAddis]

I had my alternator reconditioned at a local specialist for approx 100 quid. It solved the flickering headlight problem that sounds the same as yours.

Ian A.

ozzie said: Between 1/2 to 1 volt variation - can be seen (and heard) in the headlights, dashboard light and the dashboard fans. Also noticeable under acceleration. The frequency is about twice a second.
I was thinking about getting a new/reconditioned alternator- what is the cost of this? and is it absolutely necessary, i.e. it is something I can do myself?

Thanks for your help - I've had this now for about a year!

Anthony.