Battery light going on and off with revs

[flashman1207]

Hi, so recently have noticed that when accelerating or generally at high revs the battery light comes on and then goes off again with lower revs. My in car voltage gauge says battery is charging (13.7v) so what can be problem? is it the exciter diode and a) can they be replaced and b) is there a way to test them?

Cheers

[PeeBee]

Hi, so recently have noticed that when accelerating or generally at high revs the battery light comes on and then goes off again with lower revs. My in car voltage gauge says battery is charging (13.7v) so what can be problem? is it the exciter diode and a) can they be replaced and b) is there a way to test them?

Cheers

Sounds like the regulator. car should be charging at 14.3 until the battery equalises.

[flashman1207]

Sounds like the regulator. car should be charging at 14.3 until the battery equalises.

Sorry, I should have said 13.7 - 14.3 volts. At high revs voltage is at 14.3v

[mudnut]

Yep diodes or regulator. If the car is a later model, alternator is regulated by computer.

[flashman1207]

Yep diodes or regulator. If the car is a later model, alternator is regulated by computer.

Nah, 94 GQ TD42.... Are regulators or Diodes replaceable or is it a new alternator?

[mudnut]

Also check that the earths, battery, and alternator connections are all tight, and that the plug on the back is pushed all the way in.

Replacing individual components depends on the condition of the slip rings, the bearings and the ability to get the fasteners out.

I have reconditioned a few alternators, and have also made and fitted a simple-to-build regulator to some. One alternator beat me, because each screw that held the delicate components was seized.

[flashman1207]

Also check that the earths, battery, and alternator connections are all tight, and that the plug on the back is pushed all the way in.

Replacing individual components depends on the condition of the slip rings, the bearings and the ability to get the fasteners out.

I have reconditioned a few alternators, and have also made and fitted a simple-to-build regulator to some. One alternator beat me, because each screw that held the delicate components was seized.

Would you have a source for parts and which ones I would need if it was a) the regulator or b) Diode

Cheers

[mudnut]

Local auto elecs should be able test your alternator and recommend the way to go.