Re: Alternator Question!

[jtrealty@xxxx]

You are right, I stand corrected. The rear defogger as it is is 
supposed to have a timer. I must admit though I can't tell if it is 
timming out, on my car the light stays on as long as the switch is on 
and I always hit it with my elbow! If not for the light I woudn't know 
I had it on and if the heater does go on and off the light doesn't. 
Maybe my timer relay is defective, I never checked it out. I have 
observed that on cars with a sloped rear window they tend to fog up 
faster and more often, the more slope the worse the condition. In the 
Delorean the rear window is almost vertical and so does not fog up as 
fast. Maybe the engine heat also has something to do with it. In any 
case by limiting the duty cycle of the biggest load (short of the 
starter) it limits the peak load imposed on the system. IMHO if you 
can't get by with the 90 amp Motorola and you have not measureably 
added to the car's electrical load then the battery probably has lost 
some of it's capacity or maybe you are stopping and starting the motor 
too often and not fully recharging the battery. Cars were meant to be 
used on a regular basis and a battery loses a small percentage of it's 
charge every day. If not a daily driver then the battery is usually 
chronically undercharged. Don't forget we also deal with a very 
complicated and leaky courtesy light circuit with all of those diodes 
and the clock (although a small draw they are all cumulative). By 
putting a larger output alternater on the car that can create more 
electical power at a lower rpm you can't get something for nothing. It 
will cause a larger drag on the motor at low rpm's and could possibly 
affect the idle quality. Putting a smaller pulley on it besides having 
the effect of spinning the alternater faster at low rpm's also reduces 
the mechanical advantage the motor has increasing again the load on 
the motor. Beware of "improvements" that have not stood the test of 
time and have been thourghly engineered. 


--- In dmcnews@xxxx, Jan van de Wouw <Jan@xxxx> wrote:
> David Teitelbaum wrote:
> 
> >On most cars (not Deloreans) the rear defogger is
> >shut off by a timer to keep it from running constantly. Maybe that 
is
> >a good area to improve, adding a timer to the defogger instead of
> >increasing the alternater.
> 
> I'd like to quote the ownersmanual (page 11) on this:
> 
> > Rear Window Defogger Indicator
> > This indicator will illuminate when the defogger is in use.
> > The system incorporates a timing device which automatically
> > switches the circuit on or off in a continuous cycle of
> > several minutes duration for optimum efficiency.
> 
>--------------------------------