Did I fry the alternator?

[abcnuzeman]

Heading out this morning, I noticed what appeared to be smoke in the cabin. I throttled back, opened the engine compartment on my CD 25D but could see no cause and the smoke seemed to dissipate. I turned back to my slip and tied up. During the time I noticed my VHF kept shutting down with the message "high voltage". When I checked the voltmeter on the switch panel, it was pegged at 16v. I shut everything down and opened the battery compartment and noticed a little remaining wisps of smoke. Later, I remembered absentmindedly turning to key off while the engine was running on my last sail, realized my mistake and quickly turned the key on and shut down the engine normally. Since all seemed normal when I started the engine today, I assumed no harm no foul. Did I fry the regulator, the alternator or do some other unknown and no doubt expensive damage?

[JWSutcliffe]

Been there, done that. Only takes that one absent minded turn of the key or inadvertent battery switch to OFF and the alternator diodes are toast. On the plus side, its a quick fix.

[Steve Laume]

I don't know what might have happened in your case. It could depend on how things are wired but something is, obviously. not right.

On Raven, the alternator output is wired directly to the positive post on the main battery bank. You can shut the engine ignition switch off or the battery selector switch and nothing bad will happen. This was recommended when I upgraded my charging system.

If you are going to be messing with things anyway it might be a good idea to reroute the alt output, Steve.

[JWSutcliffe]

This is exactly what I did after I fried my diodes - routed the output straight to the battery bank nd bypassing the switches. Saves a LOT of headaches.

[tjr818]

This sounds like an easy thing to do, BUT . . . I seem to remember something about the starter motor and the alternator using the same wire I think it might have been Main Sail talking about battery combiners that mentioned this. Now I am really confused .

[abcnuzeman]

Thanks for the feedback. On reading my engine manual, I'm pretty sure that I've fried the diodes in the alternator and perhaps smoked the wiring harness as well, which would account for the smoke. In reading the manual, the disassembly runs to almost five pages and includes several cautions about unsoldering connectors and removing rivets to get to the regulator. All well beyond my skill set. When this was mentioned as a quick fix, does that mean removing the alternator and taking it to a repair shop or replacing the alternator? Any guidance from the august forum is deeply appreciated.

[JWSutcliffe]

I used a local automotive electric shop. They replaced bearings, brushes, diodes, regulator and tested the alternator for less than $100 and 2 days.

[abcnuzeman]

Thank you Mr. Sutcliffe...exactly what I needed to know.
David Owens