[s-cars] Battery update, C4 A6

[Huw Powell]

Kent McLean wrote:
> JC wrote:
>> Kent - Good process except also with the 5000/200 there's the notorious main
>> positive cable splice which can corrode and go short or become resisitive -
>> so always a good thing to look into early in 200 battery problems.  To copy
>> the  instructional style: 1. Connect ohmmeter (using long cable) to
>> disconnected positive battery cable under seat and to positive alternator
>> connection in engine compartment. 2. Is there excessive resistance?  3. Now
>> Connect one end of meter to gound. Is there leakage (less than infinite?) 4.
>> If yes to either one, repair or replace main battery cable...
> 
> Another good point.
> 
> What constitutes "excessive resistance" through the cable splice?

Another approach to testing this is to measure the voltage to ground 
under the hood, say at the jumper post, and the voltage to ground at the 
battery plus terminal.  Do it with some electrical loads on - headlights 
and blower fan, say.

If the voltage at the battery plus terminal is more than, say, .2 volts 
less than under the hood, that cable needs repair.  If the voltage at 
the battery is below 12.6 volts it's not even getting a charge at all. 
It should be over 14v at both places if you have a nice voltage regulator.

None of this really relates to the battery going dead over time while 
not running, except that it can leave you with a weak battery to start with.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/