alternator

[Tom Goldman]

Originally Posted by Jack Zimmerman

An alternative to the relay to shut the power off to the alternator when in the trailer or in storage is to use a Cole Hersee P/N 75912 double pole battery disconnect switch. The main battery cable gets wired to one pair of terminals and the alternator field cable to the battery goes through the other pair.

Jack, I used to use those on all my builds ,but in recent years I and several of my customers experienced switch failures . .that prompted my switch to the relay which has been very reliable. The 75912 switch is US made now [previously it had been being made in Mexico] and is rated at 750 amps intermittent load . Some of the 4 post type switches that that are being sold by Jegs ,Summit and others have smaller gauge secondary terminal posts are only rated for a 30 amp load and will not survive the output from the alternator.