Yeah, well, I suppose the only persons who actually /need/ to know the
power draw of the engine alone would be those whose alternator failed and
they were looking at getting home on the battery and thinking, ". . . okay
this is a 40Ah battery . . . I wonder how long it can power the engine?"

That would be the ECU, fuel pump, ignition bits (coil und so weiter),
various senders and sensors stuff; and not counting headlights, radio, etc.

My interest is really on what your 90A Bosch alternator has left over
after taking care of the engine.

I recall that the engine in my (now sold) 71 aircooled baywindow could
drain a battery pretty quickly and all it needed for power was for
ignition. No ECU, the fuel pump is mechanical, there's not even a temp
sender.

Anyway, Mark Drillock provides the method to measure the numbers I need. I
guess my in-depth article on aux battery charging -- which includes
excellent calculations of wire sizes based on available power from such
sources as your starter battery and alternator and takes into account such
subtle matters such as internal resistance of typical lead-acid batteries,
and which is intended to provide worst-case scenario for wire diameters
and relay contact ratings, will just have to wait.

Simply a tragedy -- a tragedy, I tell you!

--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
Bend, OR
KG6RCR

On 8/21/2009 5:50 AM Richard A Jones wrote:

>> I am hopin' this is some bit of information that is commonly known.
>
> I asked the same question a couple of years ago and got nowhere,
> so I'd say "it is commonly known that it is not commonly known...."
>
> Richard
>