Re: [ihc] Re: Humphrey's Coil Voltage

[John Hofstetter <hofs@xxxxxxxxxxxx>]

on 3/23/04 12:32 PM, George B Humphrey at xgbhx@domain.elided wrote:

> 
> Yes, a big part of the fuse panel is on in both the start and run
> position but that is the boat I am in now. During cranking the voltage
> drops and opens the relay. I picked the heater circuit because I never
> have the heater running while I am starting the Scout. My other choices
> are, radio, turn/back up, and tail and panel. All of which will drop in
> voltage during start. If the lights are on the lights will dim during
> cranking. The radio lowers in volume. The remaining two circuits are
> always on, stop/hazard and horn/dome. That's all my fuse panel has.

I think, now, that you were not seeing the big picture. There should not be
that kind of voltage drop when starting unless you are having to crank a
long time. 

In my opinion, you need to have the starter tested for amperage draw. Steve
Stegman had a starter that was drawing 450 amps or so. Maybe you are too.
Starters draw that kind of current when the armature is dragging on the
field coils. I imagine that we can assume that you made the Ford conversion
because the starter was having problems. Maybe part of that problem was
starter draw. 

What gauge cable do you have going to the Ford solenoid and then down to the
starter? Too small a cable will cause the effect you are having, especially
when paired with a dragging starter.

Proper amperage varies with the engine and starter, but over 250 amps would
cause me concern. In regard to testing, I have a cheap starter tester that
you lay on the cable and get a reading inductively. Works great although its
accuracy may be off 15 or 20%. No big deal.

I think it was Jim Grammer that found one at JC Whitney a year or two ago.

When starting, my battery maintains 10.7 volts at the battery terminals.
That will keep your relay closed. Your headlights should dim some, but not
dramatically. 

John Hofstetter