Re: Happy New Year(recent trip)

[steveb@newkla.kla.com (Steven Buchholz)]

WRT the voltage measured by the diagnostic computer - Remember that 
the sensing is done using a wire with finite resistance and that there 
are other loads at the end of the wire.  This means that some of the 
voltage reductions seen by the computer are simple IR drops in the 
wire ... the battery & alternator are just fine!  My '78 Fox came with 
a VDO voltmeter that was on the same line as the fresh air fan.  When 
you turned the fan on high the voltmeter would register 10 volts but 
the battery voltage was more normal.  The other thing to keep in mind 
is tht the "natural" voltage of the battery is 12.6 volts, so if you 
see readings of this value or higher you know that the battery is not 
being discharged (but it may not be charging either).  The voltage 
drops seen when you turn on the lights and the rear window defroster 
really do reduce the voltage seen at the battery, but the stereo & 
climate control probably don't (but then I haven't seen your stereo ;-).

The only thing you might want to do is to get one of the elctronic 
trickle chargers that sense the battery voltage and shut themselves 
off when the battery is fully charged and use it to top up the 
battery's charge every few weeks (especially in the wintertime when 
you do more driving with the lights, wipers & defroster on).  Mine 
has a max current supply of 3 amps, so I rigged up an adapter that 
plugs into the cigarette lighter ... pretty painless!

Steve Buchholz