Circuit breaker woes
 

I have a 25' SST with a 502 MPI. I have a problem somewhere betwen the alternator and cuircuit breaker. When I start the motor the voltmeter reads 13.5 volts and everything is fine. After it idles for a couple minutes, the voltmeter indicates a drop in voltage to 10.5-11 volts. The motor continues to idle and run fine. Increasing the RPM's has no affect on voltage at that point. I can then shut the motor off, push the 50 amp reset, it just barely clicks when i do this. Then when i restart the motor i have my 13.5 volts for another couple minutes, then it trips out and drops voltage. I've had the alternator checked at a shop and all is well with it. Any help from the good folks at OSO would be greatly appreciated.