Alternator charging issue AQ131a

peradetlic

Cadet
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Apr 10, 2014
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Another problem Inoticed on my Bayliner Capri 1987 that I got about 4 years ago:

Ever since I got it, the alternator wouldn't charge batteries (voltage readout about 11v on the dash) until about 5 minutes into driving, then the voltage would go to just shy of 14v. Never bothered me enough, or caused any issues to look into it. (I red in the manual that alternator needs some RPM to start giving power, so i assumed if that was a mechanical circuit it was getting stuck, and needed some heat and vibration to start working :) )
However, last weekend it wasn't charging at all. I checked "usual stuff" recommended by service manual. And I got puzzled:
Alternator output, that goes to starter and battery measures within the range impedance.
Stator impedance measures pretty high, in megaohms.
When engine is running, there is no charging, battery voltage is the same as before engine was started.

I noticed that voltage from ignition goes through the resistor to the stator. Before the resistor (ignition switch side) there is 12V, but on the stator side there is 2V. Resistor measures 70 ohm

Is this normal? I though that stator is using low current, and that voltage on stator should be 10-12v. Am I wrong here? Is resistor bad? Can I, just for testing purposes, connect 12V to stator to see if it will charge?

It is Paris (something) 60A alternator (I guess Valeo is the same type, with regulator sticking out in the back).
Can this alternator, on this boat, be replaced with "one contact" alternator, self inducing or self polarizing, or whatever it's called.? The one that just connects to the starter/battery, not to ignition switch.

THANKS!
 
Last edited:

captmello

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3,826
Re: Alternator charging issue AQ131a

You need a marine rated alternator, I would bring your current one into a rebuild shop and have it checked out. Most can be rebuilt for a reasonable price.
 

peradetlic

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Re: Alternator charging issue AQ131a

eBay has marine type alternators with blast screens for $70-$130. Some are one contact, self exciting. Several years ago when I had car alternator rebuilt it was $120. It looks to me that it is cheaper to replace the whole alternator. I know they are not the same quality as mine, but refurbish shop will also put some no-name parts. original regulator with brushes itself goes for $300+. Plus diodes, bearings...
Any thoughts, suggestions? Is my reasoning valid at all?
 

bruceb58

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Mar 5, 2006
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30,454
Re: Alternator charging issue AQ131a

Your main problem will be if the self exciting ones will fit your engine.
 

peradetlic

Cadet
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Apr 10, 2014
Messages
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Re: Alternator charging issue AQ131a

Yes, eBay auctions say "slightly bigger". Thank you for pointing that! I think I will stick to the regular alternator, the same size. I can hear bearings on mine, so I decided I should replace it.
Now my question goes about the resistor: is 70 ohms the correct value, and why am I seeing 2V after it? How much current goes through the excitor/stator?
And will I need that resistor with the new alternator (auctions say "just bring 12V from ignition switch"). If not, should I put a fuse in series, in case alternator shorts ignition switch doesn't get damaged...
Thanks for all the inputs!
 

bruceb58

Supreme Mariner
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30,454
Re: Alternator charging issue AQ131a

Take your to an alternator shop and get it rebuilt. Does it have an internal or external regulator?
 

peradetlic

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Messages
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Re: Alternator charging issue AQ131a

I think it is called internal, it sticks out at the back of the alternator. It is Paris Phone/Valeo 60A alternator.
Can any alternator shop rebuild it, or should I look for shop specialized in marine alternators?
Thanks,
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Re: Alternator charging issue AQ131a

Any alternator shop can do it. The marine aspect is a mechanical issue(screen) which the re builder shouldn't touch. Of course tell them it's marine so he doesn't substitute cases on you.
 

peradetlic

Cadet
Joined
Apr 10, 2014
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Re: Alternator charging issue AQ131a

Huh, alternator shop said it is not rebuildable. They couldn't open it, the bolts started cracking. Anyway, the guy told me that it was rebuilt once, already, and that rgulator was generic one, not original Paris Rhone... I'm getting come "Caltric" brand from eBay for $130 give or take. Yes, it is for gas marine engine, with spark arrester screens. Direct fit, 60A.

BTW, I called a "nearby" Volvo Penta service and asked about the "resistor" that is attached to the "ignition" contact on alternator. It is combination of the resistor and diode inside, without it the engine keeps running when you turn the ignition off-there is often enough juice leaking back from the stator to keep engine running. With a digital ohm-meter it measures 75 ohms.

Again, thanks everybody for reading and helping!
 
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