I had a rebuilt alternator installed this summer to replace one that appeared to have died. After a few weeks of operation, the replacement also appeared to have gone south.

Yesterday, a dock mate who knew infinitely more than I about electrical trouble-shooting (actually, my knowledge base is slightly more than zip, just the ability to measure voltage with a multi-meter), spent several hours helping me figure out what was wrong. He was doing lots of "hmmm, that shouldn't be" and head-scratching. At one point he asked me about the circuit breakers on top of the engine, just behind the alternator. I tapped one of them but, while it clicked a bit, didn't seemed to be in a raised, tripped position. But shortly thereafter, when we started the engine and measured voltage at the battery, the alternator appeared to be back in business. The only other measure we took was to take apart and reconnect the wiring harness.

So...can someone shed light on what this breaker actually controls? What may have caused it to trip in the first place? How is it related to the alternator?

My new best-friend feared that with the zero output symptom, the alternator may have Had blown diodes. HE wondered whether I had used the battery switch to shut down the engine (I don't do that, ever). And, feared that if the diodes had blown, changing the alternator again might result in the same problem, blown diodes. But we are back in business and I left the marina with a big smile on my face (for now at least).

Oh..one other interesting thing: the other engine alternator was doing OK, measured at the battery. But the dash board volt meter always registered low (about V or a little under)which never bothered me. Yesterday, after only only disconnecting and reconnecting the wire harness, the meter now registers a more correct V+. Hmmmm.

Finally, another important question, probably for Norm, the western world beer champ: What is a high-end product that I can buy a couple cases and deposit on his boat? No cheap crap. (And a second choice in case my local guy doesn't carry your first recommendation)

Joel:
It depends on which breaker tripped.
There are 2 klixon "push-to-reset" breakers on top of the chryslers. One is a 25 amp and the other is a 50 amp. Your alternator output goes through the 50 amp breaker. The power that feeds your alternator regulator (and the field terminal on your alternator) goes through your 25 amp klixon breaker. In fact, all other 12 volt circuits are fed through that 25 amp breaker. So if you overload any of those circuits or have a short, the 25 amp breaker will trip and your alternator will no longer be excited and will not produce. If you ever upgraded your alternators to higher output, you have to upgrade your wire to a heavier guage and re-route the alternator output to a new higher rated breaker. NOTE: the original alternators were rated at 51 amps, so theoretically, the klixon breaker could trip at max output, but in reality, alternators rarely reach their max amp output and klixons trip at 135% of their rated capacity. The klixon breakers use thermal expansion of a bi-metal dimpled disc to pop the breaker. That disc can eventually corrode and reduce its capacity.

"If you ever upgraded your alternators to higher output, you have to upgrade your wire to a heavier guage and re-route the alternator output to a new higher rated breaker."

Didn't I read that if a guy upgrades his alternator that you can run and additional matching circuit breaker in parallel if for example you did a 100 amp alternator ??? It seems fiesible but I guess I would prefer just one larger breaker. Do they make larger Klixon breakers that will retrofit into the same location ???