The battery was showing 6 volts when I disconnected it. So I jumped it off with my truck and it went back up to 12, so I 're-connected it. I'm wondering if it may just be a fuse issue. Do you know what kind of fuse I should use? The old one was too worn to read... The battery was showing 6 volts when I disconnected it. So I jumped it off with my truck and it went back up to 12, so I 're-connected it. I'm wondering if it may just be a fuse issue. Do you know what kind of fuse I should use? The old one was too worn to read...

It COULD be a fuse, if the old one was blown. If the battery went very low, the maintainer wouldn't be able to generate enough current to bring it all the way up again. The fuse - is that part of the maintainer, or part of the boat? It's really hard to say what current rating you should use without knowing either how much current you actually require and what size wire you have. You COULD connect an ammeter in series with the fuse, then intentionally TEMPORARILY put too big a fuse in, just long enough to read real current, then install a fuse that matches your actual current use. First, though, I think I'd hook that battery back up to your truck & charge it that way for an hour or two. That'd take away all the hard work for your maintainer. It COULD be a fuse, if the old one was blown. If the battery went very low, the maintainer wouldn't be able to generate enough current to bring it all the way up again. The fuse - is that part of the maintainer, or part of the boat? It's really hard to say what current rating you should use without knowing either how much current you actually require and what size wire you have. You COULD connect an ammeter in series with the fuse, then intentionally TEMPORARILY put too big a fuse in, just long enough to read real current, then install a fuse that matches your actual current use. First, though, I think I'd hook that battery back up to your truck & charge it that way for an hour or two. That'd take away all the hard work for your maintainer.