Some notes. You most probably have a 130 amp 4G or 6G alternator. It will stir fry a standard 60-80 ampere cheap solenoid switch. I used every switch type metal can type solenoid on the market on a Ford Van (locksmith's with electric machinery and inverter) SIX DIFFERENT BRAND SOLENOIDS LATER, Lisle Bruney of Sure Power advised me their ONE HUNDRED AMPERE RATED solenoid was inadequate to do the job. That's when they decided to make the 200-amp rated unit. The vehicle had a 3-G 130 amp alternator. Lesson learned.
When FAST is important the goal is to send power directly off the alternator output stud through a suitable breaker or fuse, through a battery isolation device to a SECOND breaker or fuse near the house batteries.
You may end up having to use FOUR GAUGE WIRE from the alternator output stud to the house batteries to do this.
The Sure Power 200 amp bi-directional rated "Smart Solenoid" would be my choice. I hate it when I have to screw around with unnecessary switches and run a vulnerable switch to solenoid wire. Buggy Whip technology.
