[BruceK]

Gumbalaya, You`ve not said how long you owned the boat,but as I understand it you`ve never run it except for a test, don`t know the brand or the output. Onan says run it weekly for at least half an hour, I think mainly to maintain the generation.
I think you`ve established you don`t need it. But,someone else might when you eventually sell,and depending when, it might still be repairable and help you sell it. If that`s not persuasive,you have a good place to locate some more batts for a truly genset free boat.