This just started this season. Solar voltage fluctuates between 0.5v and 6v every .5 second when the 100w panel is in direct sunlight. Wires at the MPPT terminals read 18v+ coming from the panel, so none of the cable connections appear to be the problem. I'm using a BMV-712 as well, which has been monitoring just fine. Anything else I can test, or is it a busted unit? Thanks!