battery switch

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john watermeier

battery switch

Post by john watermeier »

on a guest or perko battery switch,what does the "F" and the "C" terminals represent?thanks



johnwater@hotmail.com
Bob Ohler

Re: battery switch

Post by Bob Ohler »

John... perhaps you're misreading those marks... I suggest that "F" is really "+"...indicating positive (is the cable red?)....and "C" is common, indicating common ground (negative, black cable). That's my guess. Bob O.
john watermeier wrote: on a guest or perko battery switch,what does the "F" and the "C" terminals represent?thanks


bobohler@chesapeake.net
john churchill

Re: battery switch

Post by john churchill »

john watermeier wrote: on a guest or perko battery switch,what does the "F" and the "C" terminals represent?thanks
first a disclaimer - i dont have one, so all i have is book learning. the books i have say there should be three terminals. "1" gets a hot lead from one battery positve terminal, "2" gets a hot lead from second battery. "C" is the common feed which should go to both the starter and the main electrical panel hot bus bar. on some installations, the main panel feed is off the starter. any further questions, you may want to try calling guest directly. they put out a little pamphlet on the topic. the best book i know is the "12 volt doctor's" series by weems & plath



jchurchill@erols.com
Tom Coons

Re: battery switch

Post by Tom Coons »

john watermeier wrote: on a guest or perko battery switch,what does the "F" and the "C" terminals represent?thanks
All the leads going to a battery switch are positive (red). Whatever you do, don't attach a negative (black) wire to the battery switch or you'll have a dead short across your battery. You'll fry your switch, proablbly your battery, and may start a fire.



TacCambria@thegrid.net
Jim Jones

Re: battery switch

Post by Jim Jones »

If the "C" terminal is large ( 5/16"-3/8" ) diameter, then it is the COMMON output from the battery switch.

If the "F" terminal is small ( approx. 1/8" ) then it is the field coil disconnect wire. In order for any alternator to work correctly it must have an "exiciter" voltage supplied to the field coil. This voltage is usually supplied directly from the ignition switch when you turn it on. When the battery selector switch has the "F" post, you can wire directly from the field coil of the alternator to the "F" post.

Most battery selector switchs have "make before break" contacts so that in any position ( 1, BOTH, 2, etc, ) other then "OFF" you can switch through the positions without damaging the alternator. The batteries act as a load for the alternator and if you remove the load while the alternator is running with the field coil powered up, you will blow the rectifier diodes in most alternators.

Most battery selector switchs have a WARNING printed on the face telling you not to put the switch in the "OFF" position while the engine is running - this would disconnect the load ( batteries ) and blow the diodes.

Some battery selector switchs come with an "F" terminal and if the field coil is wired to them correctly, then the field coil will be disconnected if you switch to the "OFF" position and the diodes protected.

If you have a simple volt-ohm meter you can check this function, otherwise find someone who can check it for you and make sure it is working correctly.

Good Luck,

Jim Jones



jjones@intergate.com
Steve Alarcon

Re: battery switch

Post by Steve Alarcon »

Bob Ohler wrote: John... perhaps you're misreading those marks... I suggest that "F" is really "+"...indicating positive (is the cable red?)....and "C" is common, indicating common ground (negative, black cable). That's my guess. Bob O.
john watermeier wrote: on a guest or perko battery switch,what does the "F" and the "C" terminals represent?thanks
Careful!!!! THE "C" IS NOT COMMON GROUND!!!!!!!!; it is hot and any ground connected to it will cause a short endangering vessel and occupants! That terminal provides a common path for the two legs from the two batteries to the positive bus. When one or the other battery is switched on, the "C" terminal will be live; when the switch is set to off the "C" terminal will will be dead. The diagrams in the original documentation are not electrical schematics, but they do represent the layout accurately...study them if you have them. Also, it might be worth your while to purchase a volt-ohm meter and become familiar with it's use. That tool will allow you (along with some concentrated thinking) to solve most any electrical problem.

Good luck!

Steve Alarcon
CD30 Temerity
Seattle



alarcon@internetmci.com
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