My trailer came with cigarette lighter connections between the (external) battery and trailer internals. The female housing is built into the fiberglass and wired to the inside. The male connectors are wired to the battery. For the obvious reasons I would like to replace these with something more robust and weatherproof. A key consideration though is to fill the round hole with what is sure to be a square or rectangular plug? I would like to minimize the amount of caulk/fill/gasketing necessary. Any ideas? Thx