Date: Fri, 21 Aug 2009 09:20:45 -0700
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Engine electrical power requirements?
In-Reply-To: <71d9cdf90908210822v3e3a7c11od489ecdb472e9b27@mail.gmail.com>
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You could be right. The ECU does have a bit of heatsink along one edge but
it's expected, in the 1.9 at least, to operate in a darn hot location. So
yeah, it might no be using a lot of power.
What does it do for a living other than active the fuel pump relay, read
inputs, and drive the injectors?
--
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 8:22 AM Jake de Villiers wrote:
> Our race car had no alternator fitted and would run the starter, fuel
> pump, gauges and ignition for 2 practice sessions and a race without
> needing to be recharged.
>
> Prolly the biggest consumer would be the oxygen sensor - I can't see the
> ECU needing bags of current...
>
> On Fri, Aug 21, 2009 at 8:01 AM, Rocket J Squirrel
> <camping.elliott@gmail.com <mailto:camping.elliott@gmail.com>> wrote:
>
> 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
>
>
>
>
> --
> Beverley Anne de Villiers April 20, 1930 - July 4, 2009
>
> Jake
>
> 1984 Vanagon GL
> 1986 Westy Weekender "Dixie"
>
> Crescent Beach, BC
>
> www.thebassspa.com <http://www.thebassspa.com>
> www.crescentbeachguitar.com <http://www.crescentbeachguitar.com>
> http://subyjake.googlepages.com/mydixiedarlin%27
>
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