Wednesday December 1, 2010
I have wondered why my 55amp alternator never puts out more than about 20amps. I have turned lights and all kinds of inverter loads and the amp- meter never reads more than about 25 amps. SO, I traced the alternator's output path.
Looks like at the alternator, there is a #8 size wire that had a failing crimp connection. Fixed that and no change in amperage out of the alternator. So where does the other end of the wire go? The other end of the alternator wire went to the wiring closet behind the helm to a screw terminal. The other side of the screw terminal went to the dash amp-meter with #10 wire (30amp capacity!). The other side of the amp-meter was wired with #10 wire down to another screw terminal and then to the common side of the battery switch. I have not been able to measure the resistance of this path of about 20 - 30'. But, That is a crazy path to get back to either house or starting battery. Kind of backwards going from the switch towards the batteries. I will probably purchase a shunt type amp-meter and wire the alternator to the starting solenoid battery connection. This would be less than 3' and would have basically no loss from the alternator to the starting battery. Of course the cool Blue Sea Systems 120 A SI* Automatic Charging Relay (ACR) will take care of charging when the alternator is operating and isolating the house battery when the motor is cut off and the alternator stops.