Date: Wed, 5 Feb 2003 23:56:39 -0000 From: "Jez" <jl.webnopsamorld.com> Subject: Re: Faulty alternator connection or a nuance of Saabs?
"Grunff" <grunffnopsam.com> wrote in message news:b1s1hs$169njl$1nopsam52899.news.dfncis.de... > Johan Beikes wrote: > > Not quite rubbish. The alternator needs a magenetic field at the stator in > > order to generate a voltage and start delivering a charge current. The > > magnetic field builds up by a current supplied by the battery. If the > > battery is _really_ flat, then the stator magnetic field will be very weak, > > so a high charge cannot be expected. Not until the battery reaches a certain > > voltage by the low charging current. So, yes it can take a couple of minutes > > before high charging starts. > > Erm, but if the battery was that bad, you wouldn't have a hope > in hell of powering your ignition system. No, although I see > what you're suggesting, I don't think it's a mechanism which > could cause a measurable drop in charging for the first couple > of minutes. > > -- > Grunff > I think I may have made a mistake: the vehicle recovery (rescue service) man attached a battery pack to my car's battery rather than using jump leads from his vehicle's battery. I understand next to nothing about cars, but I get the impression I've phrased things in a misleading way - sorry if that's the case. Another detail which might help clear things up a little is that last night I had a neighbour jump start my car (by battery-to-battery jump leads with his engine running): I disconnected the leads very quickly as I wanted to let him go back indoors, and my engine managed to run for a couple of minutes and then cut out even though I was trying to keep the revs up, parked and in neutral. I pass this on just to reduce any mystery or misunderstanding. Now, thanks very much to you all. Once again I find the people on this NG more helpful and better informed than the guys I pay! The theory about no/low initial charging seems more likely to me than a loose connection, and that's the main thing for me at the moment. Ian, I probably should mention that my local mechanic said that if there had been no connection due to a loose wire the battery warning light would have been on, which suggests to me that you could be giving a fuller explanation for something he has observed, rather than that there's a big difference of opinion there (?). Anyway, thanks again, Jez