You most likely have the standard WFCO 3 stage converter.
I've had two trailers with them and never any issues keeping them plugged into shore power. Just checked the water levels once a month.
Dan-Retired California Firefighter/EMT
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package