I bought a used TT, 2002 Conquest (Gulfstream). Long story short I plugged the TT into shore power w/o a battery, burned out a number of light bulbs. Installed a Walmart Deep Cycle Marine battery and replaced the burned out light bulbs and everything seems fine. However using a digital multimeter I see the light receptacles are getting about 18v. Where power is coming into the fuse panel I am also getting 18+ v. At the battery I am getting 16v. All these readings seem high to me. Anyone?s thought? The converter is a Magnetek 7345. Thanks for any guidance.