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- Newsgroups: rec.autos.vw
- Path: sparky!uunet!newsflash.concordia.ca!hobbit.ireq.hydro.qc.ca!marcouil
- From: marcouil@ireq.hydro.qc.ca (Luc Marcouiller)
- Subject: Re: Those annoying lights...
- Message-ID: <C19AnD.D12@ireq.hydro.qc.ca>
- Sender: news@ireq.hydro.qc.ca (Netnews Admin)
- Reply-To: marcouil@ireq.hydro.qc.ca
- Organization: Hydro-Quebec
- References: <1993Jan20.042412.26700@Virginia.EDU> <1jjlk0INN5op@phantom.gatech.edu>
- Date: Fri, 22 Jan 1993 12:57:12 GMT
- Lines: 39
-
- In article <1jjlk0INN5op@phantom.gatech.edu>, grahamt@phantom.gatech.edu (Graham E. Thomas) writes:
- |> ejv2j@Virginia.EDU ("") writes:
- |>
- |> >I own a 1986 Jetta four door with 90K miles, which I bought
- |> >used two years ago. Every time I start it up, the
- |> >dash lights corresponding to the oxygen sensor and the battery
- |> >come on and stay on until I rev past about 1500rpm; then I
- |> >don't see them again until the next time I start the car.
- |>
- |> >When they do go off as a result of revving the motor past about
- |> >1500rpm, all electrical features suddenly work more strongly --
- |> >the headlights brighten slightly, the fan blows a bit harder,
- |> >the interior lights brighten perceptibly.
- |>
- |> It's not a problem. My mom's Jetta does the same thing, as to
- |> many cars I've driven. After you start the car, the battery is
- |> a little bit drained. When you rev the engine, you charge the battery to
- |> it's full capacity, so the light goes off, and your lights get brighter.
- |>
- |> That may be an oversimplified explanation. Does anyone have anything
- |> better?
-
- Well ... close but no cigars! Recharging the battery takes longer than that
- but when you rev the engine the alternator gives a higher voltage and becomes
- self-inducing thus not draining current from the battery. Self-inducing means
- that you need current to "energize" the rotor of the alt and at first it
- comes from the battery (alt idiot light on) and when the output from the alt
- is sufficient it kinds of feed itself (idiot light off).
-
- And for the record all the VW I owned did this at one point or another. Of
- course you know that they have the habit to eat trought alternators right!
- (thus my knowledge of this stuff)
-
- Share and Enjoy
-
- Luc
- --
- Luc Marcouiller, Institut de Recherche d'Hydro-Quebec,
- Chercheur marcouil@ireq.hydro.qc.ca
-