new alternator - different behaviour

[widget]

My alternator went a little while ago, battery bulb was glowing dimly at idle, and eventually went spoing on the M4 - came on bright - ECU light on etc.....voltmeter went off scale and battery bulb eventually blew - managed to limp home.

Got vauxhall to fit a new one - they said they wouldn't know how much the job was going to cost until they got the old alternator out and checked the Amps rating on it.

anyway, got new one in now and car runs fine - but......my previous alternator (before it went wrong) would sit at just under 14v on the meter, and when stuff started kicking in (like air-con and cooling fans coming on full speed) it would drop to maybe 13v. Now, it sits at just above 13v most of the time - and seems to be affected a lot more by loads than before. Yesterday with the aircon on and stuck in traffic, both cooling fans went to full speed and the voltage dropped to 12V! (I've never seen it that low before - in the 6 years I've had the car!)

Thoughts - has the old alternator damaged the battery slightly some how during its failure - possibly when it was overcharging (which wasn't very long) - OR, has the garage fitted a lower rating alternator.

...maybe I'm just being picky? dunno

Graham

[Maverick]

Hi widget. I wont pretend that I am an electrician. My alternator went and I had the choice of going with the standard V6 amp rating which worked out about 55 quid more all in. So I actually chose to go with the standard (I'm presuming) 8v/16v one which is less powerful as the lower spec cars often lack air con or heated front seats etc.

Could this be a possiblity with yours? Would be a bit naughty for vauxhall to do that

[lee683]

well if all ur lights came on and some blew the alt was overcharging. it may have cooked ur battery. so when u put load on it eg. lights, a/c, fan etc. so ur battery cant hold it charge.
best get it looked at