> Lurk Mode: OFF
>
> If you check the voltage of the battery with the engine running, and with
> the engine off, you will find a 1 to 2 volt difference.  I would
> think with
> a simple comparator circuit that you would be able to determine these two
> voltages as well as 0 volts....As long as you have backup power for the
> sensing circuit that is...

        Unfortunately the problem with just this is that the lowest "engine on"
voltage may be below the maximum "engine off" voltage when you consider all
conditions. For example, on a really cold day the "engine running" voltage
might be below the "engine off with fully charged battery" voltage. TTYL

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