Anyone have any idea why if the car is left parked up for a few days it starts fine (battery doesn't need charging) but when left running for about 20minutes it discharges the battery.

Sometimes when driving the battery light flickers on.

Aany help appreciated before i go & buy a new alternator.

 

check the thin wire on the alternator for condition but I'd say the alternator itself is knackered!

 

O.k will do now .......

 

Well i've just had a look at the thin wire as you say ........ it does seem to me that the wire is very flexible as though the whole thing is rubberised - could this be caused over time as i thought this wire should not have much play in it ........... the outside protection on the wire is very,very soft !!!

 

This thin wire only carries enough current to illuminate the warning light bulb, 2.2watt so does not need to be thick.
This live feed through bulb then excites field windings in alternator thus starting the charge process, once started it is not needed as it also then outputs positive, two positives do not make a light work and so your light goes out!!
If it discharging , at any time then then it will be the DIODES(small electrical one way valves) in the alternator contained in the RECTIFIER of it.
Odd that it should do this only when running though not impossible, it's(rectifier) primary function is to stop AC current(-) from reaching battery but has the added bonus of preventing back flow of power from battery to alternator.
So check fan belt is tight as if not could be using more power for car than you are putting back when running, then if OK replace rectifier/alternator.
A rectifier is something easily replaced(solder) around £15.
tabetha

 

Is the battery light going out?

 

i have a brand new alternator for sale

 

sold to the good looking chap with a silver cabriolet for around 17p

 

 

Yes it only flickers on now & again........

 

Thanks bud but i can get one for 60 notes - uprated aswell.

 

no worries,,
when u say it fickers the light.. it sounds like you have a dodgy wire somewhere!!

usually when the alternator has gone, the light will start dim and get brighter as the battery flattens..

 

Yes i may just replace the alternator & wiring harness as these are about the only things that were not replaced last summer on the rebuild.

 

That thin blue wire where you think it looks suspect, gently pull it, if its broken internally you will see the insulation stretching where the break is

 

Just an update - have gone & purchased a new ford alternator & battery just to be sure .......

All in for £100 both uprated aswell ........

 

I just hope its not wasted money

Whats uprated about them?

 

There both a higher ampage ...........

Well fitted today & it was big improvement - battery not dis-charging now.

BUT still have the battery light flickering on & off now & again .........

Any ideas ????????

 

See......much as i hate to say it mate you've just blown a wad and you haven't even fixed the fault...........

Re-read my posts and try again