This sounds all to interesting. I added a couple of Coast Guard surplus solar panels to my '90 Warrior a couple of years ago. I was never quite sure that they was working until this summer in Newfoundland. A couple of cool nights in the deep woods (running the furnace, and not in the full sun) left me with a drained house battery. I did some investigating and discovered that I was getting no charge off the engine. I assumed the isolator failed. When I got back into the sunshine for a day the battery recovered and the crisis had passed. The isolator had worked fine before the solar panels. And, I have no idea when it failed. It could have been years ago, or the day before in noticed the problem. Is it possible that solar charge caused the failure? I intended to replace the isolator in the off season, but now I'm wondering if something else is going on. Any thoughts?