Speakers turn off when I turn on the lights

So I've got a 2013 shockwave 5th wheeler, and when I turn the lights on, the speakers turn off, but when I turn the lights off, the speakers turn back on. The stereo stays on the the entire time. Running on Solar power. When I'm parked at home, still on solar power, it works fine. But when I'm out camping, the lights start fighting with my speakers. Any ideas? Thanks!