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Art Bianconi <British-Biplane@...>
 

Dale's right. An engine that draws 125 amps on a summer morning, can
easily drag a starter motor close to stall in the winter. As it does so
the current draw can easily exceed 150 amps; more on larger engines and
those with high compression pistons. What makes this situation so
problematical is that it occurs at a time when battery potential has been
seriously eroded by cold temperatures.

You need to design and build in anticipation of the worst case scenarios.

Art Bianconi

On Mon, 19 Feb 2001 20:09:51 -0800 "Dale Martin" <niceez@...>
writes:

My chart shows for 12 volt system you need # 4 to carry 100 amps to
the starter. An estimate of only 60 amp using #6. Starters can pull
more then people think.

Dale Martin... LEZ 777DJ
Lewiston, Idaho
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David A Froble
 

Art Bianconi wrote:

Dale's right. An engine that draws 125 amps on a summer morning, can
easily drag a starter motor close to stall in the winter. As it does so
the current draw can easily exceed 150 amps; more on larger engines and
those with high compression pistons. What makes this situation so
problematical is that it occurs at a time when battery potential has been
seriously eroded by cold temperatures.

You need to design and build in anticipation of the worst case scenarios.
Not disagreeing with any of the above. But there is an 'OR'.

Or, you control the scenarios.

Not sure if it would be practical for many, but having auxiliary power, on a
short and heavy cable, could be an option. It would be an alternative if
battery and cable weight is an overriding issue. When the engine is warm, it
will take much less onboard power to start it. Obvious complications would be
operations away from your home base, hard starting due to vapor lock or other
reasons.

I particularly liked the idea of the battery near the engine that I think Art
floated several days ago. Auxiliary starting power could be one method for
using such.

If anyone did this, it would need serious documentation somewhere. Future
owners of the aircraft would have to know about the limitations. Else they
might just put a large battery in the nose, and not ever think about the size
wiring installed in the aircraft.

Dave, just letting the mind wander.

--
David Froble Tel: 724-529-0450