Bad alternator or bad earth?

Been looking at my Golf and Battery - with the standard 60amp alternator I only get 13.2 ish volts at the battery with the alternator charging.

With the alternator disconnected it drops to 12.4 so it is doing something, but .8 volts is hardly a lot to shout about!

I tried a new voltage regulator and that had no affect (and squeaked a fair bit under load)

Could it be a bad battery/alternator earth, or do I just need a new alt altogether?

If it's squealing under load then your belt is to lose or you need a new belt, 950 x 10 is the size for a UK car.

Try cleaning the connections to see if that helps?

Where the bushes worn out on the old regulator?

mark1gls said

If it's squealing under load then your belt is to lose or you need a new belt, 950 x 10 is the size for a UK car.

Try cleaning the connections to see if that helps?

Where the bushes worn out on the old regulator?

So it's actually the regulator squeaking, not the belt - if I apply pressure to the regulator it stops squeaking, sounds like it's bedding in perhaps - but the voltage is still showing as 13.4 under load.

The old regulator was slightly worn but nothing terrible - they still seemed to make contact/were only a few mm shorter than the new one at most.

Check the size of the plastic on the regulator as I brought one which squealed when fitted and after removing it the plastic was burnt from rubbing the alternator shaft, poor quality item.

I'll see if I can find a picture and remember which one to avoid…

Edit… Topran was the new faulty regulator…

Can't seem to get tapatalk app to work to show you a picture but the new Meyle one worked for me..

This may not be your problem but could be worth removing the new regulator and checking it against the old one and clean up the prongs in the alternator which connect to the regulator.

mark1gls said

Check the size of the plastic on the regulator as I brought one which squealed when fitted and after removing it the plastic was burnt from rubbing the alternator shaft, poor quality item.

I'll see if I can find a picture and remember which one to avoid…

Edit… Topran was the new faulty regulator…

That sounds like the one I bought. It's somewhere in the shed discarded to the scrap pile!

 
Topran regulator, you can see at the bottom of the bushes the worn out plastic from rubbing.



All 3



Old regulator next to Topran one



Meyle top, Topran bottom…

Clear to see the difference!


Sent from my iPhone using Tapatalk

Legend, thanks a bunch!

Got mine here

https://www.ebay.co.uk/itm/185078471293?hash=item2b17895a7d:g:~0gAAOSwuthhpl6b

On your alternator you can add a ground from a case nut to the alternator motor mount bolt.

Verify that at the Frame ground point, you have the same voltage from the Positive connector to the block and the frame, if more than .5v replace the cables from the battery to the frame and the frame to the engine.

also see:
Alternator Tune up (Bosch 2 wire) | Volkswagen Owners Club Forum

Briano1234 said

On your alternator you can add a ground from a case nut to the alternator motor mount bolt.

Verify that at the Frame ground point, you have the same voltage from the Positive connector to the block and the frame, if more than .5v replace the cables from the battery to the frame and the frame to the engine.

also see:
Alternator Tune up (Bosch 2 wire) | Volkswagen Owners Club Forum

Nice, thanks - to confirm is the alternators positive terminal the d+ terminal or one of the other two?

The D+ terminal is the blue itty bitty wire.  it is also called the exciter wire.

The large stud is the Positive B+ wire from the battery.



Also see
Electrical System

Nice one, thanks all! After cleaning up the regulator terminals and the battery terminals I now get 14 volts at the battery!

Internal voltage meter still only shows just above 13 so probably wired that in wrong, but a multimeter direct to the battery gives 14 volts so all seems good again, fingers crossed!

no, I would see a 1 vDC difference on one of my cars, and a .05 on the other….  just think if it as normal.

Great news that it was just a bit of cleaning the contacts.