I think you should re-wire your exciter voltage to a hard line to the starting battery (or to the battery switch would be an even shorter run).
The alternator draws just a fraction of a milliamp and doesn't really kill the battery like you'd think. Non-use maintenance is to visit the boat once a month or every other month and run the generator or charger for a couple of hours. If the battery is dying sooner than that, it is probably not good.
The cycle for the alternator above is something like this Start-wait about 5 seconds-RPM up-go into exciting mode (creates a LOT of draw and power loss for a minute)- then it charges max amps at about 14.75 volts until the battery starts to top off, then it goes to about 5 amps and lowers output voltage.
You're probably popping the breaker from drawing too much through the wire to recharge the dead or bad battery. I do know that a lot of delco alternators didn't push full amperage unless the line voltage was below a cetain point. you may have one of those.
Unwire the breaker -- if the battery is bad replace it, don't crutch. check the wiring to the battery and terminals for cleanliness and resistance too. If this is the one with the voltage regulator built into the back of it, you should run the lead all the way to the battery terminal itself, then the charge leads are ok going to your battery switch. You should also have a line that goes to ground coming off the back with a lamp in series to show when the alternator is not charging. Check to see if that lamp is operating or not too, if you can't get a good ground then the charging system greatly suffers or stops completely.
Hope that helps! Charging systems are a total pain in the ass unless you've owned the boat since it was born!
I reject your reality and substitute my own.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.