alternator/charging problems

[shikta000]

ok, i've recently changed my old alternator with a 2nd hand ebay deal. while i was fitting it i fully charged the battery, this is about 1.5 years old, (during this time i've had to re-charge it approx 8 times, due to old alternator not charging/lots of short journeys). while i was trying to unscrew the blue terminal nut, from the ebay alternator, the nut it self sheared ( i can tell because the nut and bolt just rotate). i carried on installing it and i connected the blue terminal piggy-back style. when i started her up, the battery warning light stayed off, but, after only 1 day the battery became just about fully discharged. i'm wondering wether the shearing of this blue terminal nut is the cause, any advice please?

[dubslug]

i maybe wrong so wait for someone else to double check wot i say but im sure the blue wire is just the wire that sends signals to the dash to say if its charging ok or nor, have u had ur battery checked?? i would probably think its ur battery, or the voltage reg on the alternator.

[shikta000]

the voltage reg is nearly new, this is a very new problem, if the blue wire is'nt the problem i suppose i should get a voltmeter on it tomorrow to check whats happening to the currents

[rubjonny]

IIRC, if the blue wire is disconnected I believe the red light will not work and the battery will not charge.

Check the voltage at the battery when the car is off,m then check again with the engine running and under load, lights on, radio etc.

[shikta000]

ok, i'll check with my new multi-meter, thanks

[systemseiko]

Check with car switched off, battery should read 12.2 to 12.4 volts,  when running at 2500 rpm with light's,  rear demister and radio etc you should expect a minimum of 13.8 volts and maximum of 14.4,  if you see < 13.8 volts the diode pack is shagged and or armature windings/brushes.

[shikta000]

so update, i checked the voltage at the battery terminals during idle, reading was 12.5. also back to the red led light, should this light up momemtarily when ignition is turned on but not starting? i seem to remember reading in a post that the battery recharges thru this red led, therefore if i'm never seeing it light up during initial ignition then there is no power coming thru the blue wire, i'm thinking i messed it up when i sheared/snapped the bolt. i also checked the voltage reg again, its ok. i think i need a new alternator, or does anyone know if ican get it fixed at an alternator doctor? i'm in south london.

[CARPY25]

This is how the red charge light works : when the ign is switched on a live is sent to the one side of the bulb the other side is earthed via the alternator then when the engine starts and the alt starts charging the earth path becomes live as well  if you sent a live to both sides of a bulb it can't light up so goes out

rob

[systemseiko]

Have you checked the car under load yet,  as previous post suggested,  looks like alternator is  ,  a reconditioned unit should cost about £45.00

[shikta000]

so...problem solved, it was the alternator, got another one and now i'm getting all the charge i need, thanks everyone.