Please please help alternator

[Andy grim]

Thanks but seen a bosch one on ebay so will probably get that thanks for all your advice 

[Andy grim]

I tested the alternator today and with things on I got a reading of about 12.7 to 13 volts is that good was going up and down wasn't really steady

[itavaltalainen]

I assume this was with engine running but nothing else on (lights, rear window heating etc)?

If all these things are off you should be getting about 14V. 12.7V to 13V and fluctuating means something around alternator is faulty (unless your battery is completely cooked - but then you'd have massive issues starting it up).

[Andy grim]

No that is with everything on with the lights flickering could it be a bad earth?

[Bandit127]

Where did you measure the voltage? If it was anywhere other than the battery terminals (like the cigarette lighter socket) then you should measure again. Internal voltages seem to be more regulated than the charging voltage. Or perhaps there is a voltage drop on the supplies to car internal power.

I never saw more than 13.4V on my Mk3 at the battery terminals but the battery never got flat in over 10,000 miles.

[Andy grim]

No mate directly to the battery

[itavaltalainen]

I used to measure away from battery as it is a massive sink hole for electricity....

[Andy grim]

I am going to do the alternator because it sounds easy to do but I think maybe the lights flickering is a each somewhere that's not too good where's a good place to start earth wise

[gazareth]

if your engine fired up easily when the new battery was fitted then it is unlikely a problem with the main earth wire. not sure if the battery to bodywork wire being faulty would cause the flickering lights though? try measuring the charging volts directly of the alternator (thick wire from battery). if the reading goes up to 13.5-14.5 then the wire is faulty somewhere. if reading is the same then the alternator is probably goosed.

[Andy grim]

So the alternator could cause the flickering lights have any one else had the same issue also I am keeping a eye on the battery drain two days ago it was on 12.37 v have not started it in two days checked it today and it's on 12.18v is the about right or two much drain cheers also have a 063 battery is it two small looks tiny for a 1.8 petrol thanks