Alternator???

[steve j]

Advice needed please. I know the car on start needs to rev to about 1500 to charge the battery, recently my S2 needs higher revs and then on the gauge it shows 13 volts. Without warning the volts reading drops to 11 and needs more high revs to get it up to 13 again, is my alternator on the way out??? cheers
stevej

[bil]

Id check the the gauge is a true reading of the battery.

It could be that the earth/negitive connections are loose or unclean.

It could also be the brushes on the alternator, getting too short.

it could also be, battery aged and not holding charge, the alternator regulator nfg, causing under or over charging....but start with the cheap checks before changing components.

[M3CHA-MONK3Y]

Get the diode pack checked first, the same sort of thing happened to me. It took a lot of revs to get the alternator to charge and when it did, it overcharged. To the extent that on acceleration my headlights turned into HID bulbs at high rpm.

Hopefully is the diode pack as they are only a few quid to replace and can be done in situ.

HTH

[ketvrin]

Steve

is your alternator light on the dash working OK ? I believe there needs to be a load for the alternator to start charging and if the bulb blows, the load has gone and so it doesnt charge...

K

[Road2Ruin]

Mine needs approx 2800rpm when fisrt started to get charging and then every start after that on the same day it needs about 2300rpm or less. The volt meter reads ok though unless you turn a few things on.

[kenpage]

hi steve mine was doing the same i changed the small black diode on the back of the alt and it cured it be lucky