mine technically runs 2 isolators.
1 all earths before battery including winch. (need to double up but can't afford to but will be done for rebuild)
2 islotors for front and rear positive to winches.
all connections are regulaly checked and cleaned and lubricated.
not had problems yet!! i'm also running 70mm2 cable to and from winches
i haven't had over heating problems or other power problems like some I know either running 35mm2 cable or people who don't regulaly clean contacts.
Don't forget we stick thease things into crappy water just about every time we go out, if you don't clean up your connections after every event they will just furr up corrode and fail especially with the amount of power we demand.
Oh and I'm running twin maximas on a 55 AMP altornator and on th all the events i've done I have NEVER had my batterys die.