We have a Progressive Industries 50 amp unit that will shut down with either a too-high or a too-low voltage reading, and protect all components in the trailer. It's a little pricey, but what cost will you have if you have to replace several of your electrical units ? Seems good insurance to me.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.