Pics on battery cutoff switch
I don't know why you guys make it so darn hard. If you'd buy the 4 terminal (2 pole) switches, it's much easier
You have to run a BIG (say no6) charging line back to the battery, as posted here:
The problem with THIS diagram, is that there is some comments in the rules about "killing all power" and this leaves the alternator charging line hot at all times.
But it would be simple to fix: Get a "continuous duty solenoid," and mount near the battery with the contacts "inline" with the alternator chargning line. Ground one of the solenoid coil connections, run a no 14 back up front and tie it to "switched igniton". This will kill the charging line, and everything from front to back will be "dead" with the switch off.