Most people seem to regard the electrics as an occult art.
Really like anything there is a logical reason for all the things that
happen.
In Australia the internal regulator style of alternator was very popular. No
external stuff to fiddle with. One heavy wire to the battery positive and
one to the charge indicator light. It either worked or it didn't.
I haven't had much to do with relay controlled alternators. The one on my
Hunter was a self contained unit and replaced a generator.
You don't say how you measured 6.75 ohms, but it is very difficult to get
accurate low ohms readings with the normal multimeters available at lower
cost. I have specialist low ohms measuring meter that can read accurately
down to .01 ohms.
I do agree with your auto electrician that the figures you have got are not
relevant to the problem you have.
With the car parked in the garage you can measure the current leaking into
the system, just lift off the positive battery connection and insert the dc
milliampmeter. Should be fuse protected in case you inadvertently turn some
heavy current device on. There should be no current drain. Make sure the
courtesy lights are off.
One possible current drain is the "keep memory alive" connection to a modern
sound system if you have one fitted but this is so small as to
insignificant..
If you find a significant current flowing somewhere you can isolate the
cause by disconnecting circuits one at a time.
You will likely find that there is no current flowing at all, but a possible
reason for leakages is faulty switches to wipers or lighting.
The most likely reason for you battery dying problem is the battery itself.
Older batteries tend to "self discharge" over time, the only real solution
fit a new one.
Keith
55 Californian
57 Rapier
----- Original Message -----
From: "John, Sandra & Ryan Lee" <jsrlee@shaw.ca>
To: <alpines@autox.team.net>
Sent: Thursday, August 21, 2003 3:08 PM
Subject: Field terminals resistance
> The manual states you must have 3.75 ohms resistance across the field
> terminals on the alternator on a series 5. My ohmmeter reads 6.75 to
> 7.25 depending on who knows what. It varies almost every time I read it.
> My local electrical auto guy thinks it's no big deal but I seem to
> recall a thread on the board that determined if you have excess
> resistance (like I have), it would slowly drain the battery on a daily
> basis without any indication of charging problems on the ammeter. When
> in use the voltage reading at the battery seems to drop about .02 V
> /day. I,ve done the diagnostic steps as per the manual and the
> alternator control and field isolating relay seem ok. My ignition
> warning light is always on but previous advice seems to point to a
> faulty (VB) simulator. I'm recharging the battery every Sunday and
> getting by but would like to source the problem. Part of the mystery is
> the alternator was new (rebuilt) two years ago with less than 2000 miles
> on it since. Does anyone know for sure if my high field terminal
> resistance points to a faulty alternator?
> Thanks, John Lee for Ryan's series V B395000793 which is purring like a
> kitten but electrical production is not keeping up with consumption. The
> battery is fine, all terminals have been cleaned, the ammeter is non
> stock (VDO 60/60) but so what.
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