When my 1996 Ford Cargo van was pretty new installed a Bulldog security=20
system that I bought from JC Whitney. It cost about $99 as I recall.
It was pretty messy to install. The feature that I was really after was=20
the remote start. It gets really hot here in North Carolina and giving=20
the air conditioning a ten minute had start helped a lot!

It also had a feature that monitored the battery when it was off. When=20
the vehicle was not running and the battery dropped below threshold, the=20
system would start the vehicle to charge the battery. Unfortunately, it=20
did not indicate how much it was running on cold nights!

The point: There are probably after-market security systems available=20
that will provide a solution to your immediate problem and more.
If you have one of these things installed by some one else, I have found=20
that it is not likely that you will be satisfied with the overall=20
quality of the experience.

I am curious what you might monitor to to get a warning of this=20
particular failure circumstance?

On 7/22/2012 2:10 PM, Carl Denk wrote:
> Recently the wife had a dead battery with our 2002 Mercury Cougar. There
> was no illuminated warning light. Checking the cars official service
> manual, I find the following paragraph:
>
> " If there is an open circuit in the regulator (built in) or generator
> rotor circuits, the warning lamp will not illuminate"
>
> Per the owner's manual, supposedly the charging system warning is
> supposed to warn of low voltage, but wasn't on with engine running (jump
> start) and 10 volt battery voltage.
>
> In this case the fault was worn rotor slip rings in the generator
> (that's what they call it, it's an alternator).
>
> I'm thinking of adding a low voltage warning LED. Space is extremely
> limited, and yet keep the installation neat looking and visible to the
> driver, but there is an unused module between the traction control and
> rear defroster switches that an LED could be mounted. Otherwise I would
> prefer a 3 digit display of voltage.
>
> To control the LED thinking of a 12F PIC, need one ADC to monitor the
> battery (system) voltage, and one output to control the LED, including a
> flashing mode. The Pic would preferably have a built oscillator, then
> there would be voltage regulator, a couple of caps, and a few resistors.
> I still am through the hole, and not into surface mount. I do have a
> PICKIT 2 for programming, and usually use 18F13220 for my projects.
> Haven't tried to look yet for the exact PIC yet, but will after I settle
> on some of the issues here.
>
> I would have preferred monitoring the amperage to/from the battery, but
> that cable goes directly from the battery to the starter in an
> inaccessible area, and then to the vehicle system. Adding a shunt in
> that area is not feasible, though a hall effect or other device is
> possible, then if the battery is discharging for more than a short
> period,  set the warning.
>
> Thanking ahead for any comments. :)

--=20
John Ferrell W8CCW
=93During times of universal deceit,
   Telling the TRUTH becomes a revolutionary act=94
      George Orwell


--=20
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