Re: Dead battery =>ANGRY WIFE

["Paul C. Waterloo" <74543.407@CompuServe.COM>]

Joe wrote:

> From: Joe Garibaldi <joegari@cdc.hp.com>
> Date: Fri, 7 Jun 96 15:13:01 PDT
> Subject: Dead battery => ANGRY WIFE
> 
> Hello all,
> 
> The wife is ready to take my head off because her daily driver (87 5KS)
> has left her stranded twice in the past week.  MY responsibility, you
> see, is to ensure that these kind of things don't happen (to her car
> but especially to HER while she's driving it).  In order to maintain
> domestic tranquility (as well as ensuring my own safety), I beseech you
> to help me troubleshoot this problem.
> 
> As a prelude to my problem, let me tell you that we've been having a bit
> of a heat wave here in the SF Bay Area the past week, so the A/C has been
> getting quite a work-out. (Clue #1)
> 
> After the second occurence of the battery voltage going south, I took the
> car out for some data gathering.  While driving ON THE FREEWAY and under
> minimal load (i.e. no lights, no A/C, not even the radio), I monitored
> the system voltage using Channel 11 and found it to be ~ 14.3 Volts. (Clue #2)
> After turning on the lights the voltage didn't change much, only a few tenths
> of a volt. (Clue #3) Next, I turned on the A/C with the blower motor set to
> "low".  The voltage dropped to ~ 12.9 V. (Clue #4) Setting the blower motor
> to "high" caused the reading to drop further to 12.3 V. (Clue #5) At even
> lower RPMs, while driving in the city or at idle, the voltage was going as
> low as  ~11.8 V.  (Clue #6) No wonder the battery was discharging!  
> 
> What component of the electrical system do you suspect as being the likely
> culprit?  Battery?  Alternator?  Voltage Regulator?  What sayeth the 
> communal wisdom of the great and mighty Audi listers?  HELP!  My wife's
> about reached her limit.  No procrastination with this one.  If it's not
> fixed by this weekend she's threatened me that it's going into the shop.
> Wouldn't a mechanic have a field day with this one?
> 
> Anyway, TIA for your assistance.
> 
> Joe Garibaldi                                 e-mail: joegari@cdc.hp.com

I would have say the alternator components. Could very well be that the
alternator has one or more bad diodes. At low loads, it can supply at normal
voltage, but at increased loads, it looses one (or more) leg of the "Y" circuit
in the alternator, reducing output significantly.

Take the alternator off and bring it to an alternator shop. They will probably
be able to fix it within a day for about 50-60 bucks. A heck of a lot cheaper
than a rebuilt unit.


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Paul Waterloo                    TEL: (860) 267-7714
HydroAire Incorporated           FAX: (860) 267-7387
875 Old Hartford Rd
Colchester, CT  06415          EMAIL: 74543.407@compuserve.com
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