Technical Alternator Overcharging

[Misty Buff]

My battery light has been on for a while on the dash - apparently charging at about 15 and a half volts which I believe is high enough to cause problems such as bulbs blowing and cooking the battery (though I've not had any for the last 500 miles).

I was wondering if I need to replace the whole alternator, or is it possible just to replace the regulator to cure the problem?

 

[fingers99]

Check to see if the small feedback wire from the alternator has fallen out/corroded/etc.

 

[arc]

Check to see if the small feedback wire from the alternator has fallen out/corroded/etc.

This first for sure. It being unplugged will cause overcharging which brings the light on.

 

[Misty Buff]

Wow, great response, thanks guys :worship:

I've just got the car a couple of days ago and just driven 160 miles through Mid wales twisties in appalling conditions - great fun - I'm just scared of frying the electrics. Is the 'feedback wire' easily visible and fairly obvious?

 

[ycming]

Is that wire also responsible in telling the alternator to start charging the battery ?

Ming

 

[fingers99]

You'll spot it, it's by far the smallest wire to the alternator.

Ming: think so, but I don't know much about alternators. I'd suspect that the diodes do the actual work, but without the feedback wire they probably don't have a clue.