I'm looking for a simple circuit that will measure the alternator
temp and restrict current
if it gets hot. I've been told adding a resistor to the excitor will reduce the output and help it stay cool, but while I get the theoretical reason, I don't understand the practical way to do it or the risks of messing with it.
I know there are commercial
gadgets that do this, but they do more than I need and cost more than I want to spend.
Background. I've got 2 engines, same hitachi 80amp alternators on each. Each engine
connected to it's own starter battery
. And each one can switch to being connected to the newly installed lithium
house bank. Problem is when I connect the house bank to the stb alternator
it kicks out 20amps and stays relatively cool. But when I connect the port alternator kicks out 60amps and gets really hot.
So I'd like a little circuit with a thermocouple and a relay or something that throttles the output of the alternator when it gets hot.
Any info on acceptible working temps, and alternator excitor resistance values would be great.
Also can anyone explain why they pump
out two different currents? Is it do with the state of charge of the starter, or it's state of life. I think they are both pretty abused (new to me boat).
Thanks in advance.