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Old 12-31-2009, 11:32 AM
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Lightbulb One more...

After a conversation with Don I thought it necessary to post one more time with a little more explanation/info and a thought...

Don asked if I had an ammeter...
No, there isn't an ammeter in the cockpit gauge cluster. It's very possible there was one originally with the boat and it was removed.
The gauge of that Orange wire leads me to believe it was there at some point. That might also explain why it was wired that way when I bought the boat.
(That Orange wire terminated at the Ignition post with the Red positive wire from the solenoid)

Don... "I can't recall what kind of boat you have, but your voltage readings are reflective of the "Catalina 30 syndrome". The Catalina 30 has an 18 foot wiring harness between the engine and the cockpit which means that the charging circuit has a total run of 36 feet in the round trip between the alternator and the battery bus on the starter solenoid. This unusual length alone will frequently result in voltage drops much more than your 1/2 volt. Add to this unusually long distance the fact that there are three eight-pin Medallion disconnects in the harness through which the charging circuit must pass two times (for a total of 6 male/female pin connections) before getting back to the battery bus, and you can easily see why the Catalina 30 has chronic charging issues."

My boat is a Ranger 30. And it is interesting how the original wiring was. The wiring harness is somewhat similar to the C30...
It's approximately a 12-foot cable run with TWO Multi-Pin disconnects. The interesting part is that it could easily be a 3-foot run as the crow flies!
Those cables were even "wrapped" in a back-n-forth loop and wire-tied together to hold the excess wire.
Maybe the original run was designed to go to a more aft/port position, since that is where my original Depth Gauge was? (It's where I have the new Tach now)

Anyway, I mistakenly left that Orange wire run (Alt to Ignition) in when I re-wired (and put in fuses) using the MMI Drawing.
I mistakenly thought that was how it was supposed to be. (Although I questioned why alt power would need to go up and then back)

When I was troubleshooting the Tach, I read the instructions for installing the (MMI) API 55A alternator because I'm planning to go with the larger alt soon.
In those instructions it's noted that "If you do not have an ammeter, or the ammeter does not work, you can connect the output terminal of the API directly to the big battery cable on the starter solenoid."
That gave me the idea to try the jumper and the rest you know from my long-winded explanation above...

So, my reason for posting is to make sure some of you understand that the long run from Alt-Ignition and back to Solenoid is un-necessary IF you don't have the ammeter. I know this wisdom is mentioned in other threads but thought it bears repeating since some may also mis-interpret (as I did) the MMI PDF Drawing that we use to re-wire.

Again, the DC experts could certainly give us better explanations...
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File Type: pdf DCpowerschemweb.pdf (844.1 KB, 1160 views)
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-Jerry

'Lone Ranger'

1978 RANGER 30
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