nuckolls.bob(at)aeroelect Guest
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Posted: Fri May 01, 2015 7:39 am Post subject: Starter Solenoid behavior with low Battery |
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At 18:08 2015-04-30, you wrote:
Quote: | I arrived at the 10 volt figure by the hasty assumption that the
Skytec trouble shooting guide says that a voltage of less than 10 is
not a starter problem.
My symptoms are a, "bump and continue" where the prop hangs for a
second and then continues. It starts but I thought it should be better.
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Absolutely. The lightweight, PM starters are not
known for their low rpm torque output. This is
why B&C decided to stay with series wound starters
after several years of sifting the sands of
performance on the various products.
To be sure, PM starter systems impose greater
stresses on the rest of the system. They were
never a big problem in cars and trucks because
nobody balks at carrying around 20 to 30 pound
batteries, they don't have battery contactors
and don't have a system design goal that prompts
considering an external starter contactor.
I've had it in my head for about 10 years to
offer a cranking system performance analyzer
that runs out of the USB port of a laptop
and does dynamic data acquisition and analysis
of that data to identify the worst offender
voltage drops during cranking.
These are hard numbers to capture by observation
on an analog multimeter . . . impossible on
a digital multimeter. Child's play with an
agile micro-controller.
Assertions made here on the List correctly
identify the importance of high conductivity
joints and wires. But just for grins, try
putting jumper cables from your battery
to a big-honker battery and see if you
don't observe a quantum jump in cranking
performance. In my experience, battery
source impedance is a the MAJOR contributor
to disappointing starter performance
with either PM or wound field machines
. . . but ESPECIALLY PM.
Bob . . .
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