Quote: You might consider the Longacre 45782. Secondary contacts rated at 125A.
Scott
I did look at that. I'm going to run a solenoid at the alternator output and use my 2.0 feed from the battery to charge. If that has voltage drop I'm in trouble. Doug
I know it has been done this way and some people get away with it but there is a potential drawback. The alternator is a HIGHLY inductive circuit and if you just disconnect the output with a solenoid or any other means you can get potentially VERY high voltage spikes. This is also a potential problem with just about any other method that doesn't connect the alternator output to the battery side of the master kill switch. Even the field circuit can generate spikes if there isn't enough electrical load on the same circuit. In the OE configuration the alternator output is always connected to the battery and the field circuit shares a power feed with the ignition and some other loads. Also, the electronic regulators may provide a 'soft-landing' for the field current when the power is turned off.
On my track car I have a field circuit switch in reach of the drivers seat and I turn it off if a tech inspector wants to test my kill switch. The kill switch will work either way but this way the alternator doesn't need to find an alternate circuit for all that stored energy in the magnetic field.
Way back when I killed my memory tach with voltage spikes. The only items on the circuit were the alternator field power, voltage regulator, tachometer and some tiny gauge lights. The gauge lights would flash brightly if I killed the engine with the second master switch I have near the drivers seat. I've since redesigned the power feeds so there's more devices on the alternator field opwer and regulator circuit and I never kill the engine with either master switch, always using the ignition switch that shuts off the MSD box.
The solenoid will be wired with the master switch. Therefore it will be energized before starting and after the engine is shut off, no spikes. Doug
