I just bought a 1983 C36 Hull 108 and have encountered some electrical issues.
There are sparks coming from the rear of the alternator, about every ten seconds or so. This causes the power to the charter/plotter to power off and for it to re-boot. Disconnecting the alternator removes the charter/plotter issue. Other than the sparking, the alternator does charge the batteries.
The alternator is a PowerMax which is connected to a Balmar external regulator.
I am considering dropping in an identical PowerMax, with the hopes that that is where the problem is, and not the regulator (or somewhere else). I would hate to destroy a new alternator, though, if the problem is indeed not with the alternator.
What would you do? Drop in a new alternator and hope that fixes it? Diagnose more fully? Hire a pro?
Thank you!
This sounds complicated. But lets start with something simple: Where are the sparks coming from, exactly? Is it possible that there is a loose connection from one of the cables conected to the alternator -- particularly the heavy cable to the B+ terminal? Or is the B+ terminal and the cable connected to it somehow shorting to the alternator frame or the engine block (they sometimes are very close together).
If it was merely a loose connection, though, I would be surpised if it would cause the chartplotter to shut down, since there is still a power supply from the house battery bank. On the other hand, I've found that chartplotters are somewhat sensitive to voltage spikes or drops, so a short in the system somewhere might cause that.
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Everything's tight. The alternator has the two power leads, and a plug for the regulator. The arcing is in that area (i.e. not internal, or at the brushes) although I could not make out which terminals, exactly, were arcing, or if it was between termanals or between a terminal and the housing.
After more Googling, I am thinking it may be a intermittantly bad ground. She's on the hard now, but once she's back in, I will jump a ground from the block to the battery, crank 'er up and see what happens.
Thank you.
Yes, install a #8 ground cable from ground lug of alternator to the shunt near the battery. The intermittant ground will cause the failure of the alternator. Ask me how I know.
Haro
Sail La Vie 1999 Catalina 36 MKII, M35B-17031, Coyote Point, San Mateo, CA
About Sail La Vie
Yes. That would also explain why the charter/plotter would reboot at the same time. Because it is using the same bad ground.
Thanks!