Tracking down a battery drain

[TooManyAudis at aol.com]

Took the car to Advance Auto last night, had them do a charge on  the 
battery, then a system test.
 
Existing battery (4 years old -- Huw incorrectly guessed at its age being 6 
 years, resulting in 4 demerits) was putting out 500 +/- amps, with it 
being  rated for 700 amps new.
 
Put in a new battery for $100.  Rated at 850 amps with 700 cold  cranking 
amps.  Started strong this morning.  
 
The salesman at Advance did a charging system test after the install of the 
 new battery.  Results are:
 
1)  Battery:  12.56v; measured at 817 CCA, rated at 700  CCA;  Temp:  79 
degrees f.;  Good Battery
 
2)  Starter Test:  Voltage:  10.99v;  Amps:   215.8A;  Time: 1.03 seconds;  
Cranking Normal.
 
3)  Charging System Test:  No load:  14.00v, 4.4A;   Loaded:  13.47v 2.4A:  
No Problems
 
4)  Drain Test:  0.45A:  Pass
 
With # 3, my Instrument cluster voltmeter showed right around 12v with  the 
high beams on and AC on max during this test.  Is there an explanation  for 
the difference.  Is the IC voltmeter picking up voltage after the  radiator 
fan, blower fan and compressor clutch?
 
Also, with #4, is 0.45A too high?
 
Thanks for the help.
 
Tom
Charleston, SC
 
1995 A6q  5-speed (up for interesting offers) 249k
1988 80q (sold, and still going  strong!) 250k+
1991 200q20v towed away in the middle of the night by a VW  diesel pickup 
275k+
1985 4kq a freakin' beast of a car! 275k+ and presumably  still going
1987 4k died in a hit and run 250k+
1983 4k Very first Audi 35  to 38 mpg.  Victim of crank key failure 300k+  

 
In a message dated 9/29/2010 9:29:32 A.M. Eastern Daylight Time,  
glenahan at vfemail.net writes:

so why  guess? Measure the idle draw,and load test the battery. 20:1 its 
the battery.  6 yrs is 2 beyond its shelf life.

Grant
On Sep 28, 2010, at 4:14 PM,  Steve Buchholz wrote:

> I'm with Huw ... the voltage you're seeing  should be enough to crank ... 
likely high internal resistance in the battery  is the problem.
> 
> I'd also allow a bit higher battery draw with  everything off ... 10mA is 
too low IMO, I wouldn't worry until the current got  up into th 100mA range 
...
> 
> Steven Buchholz (mobile)
>