I have an MPPT 100/30 connected to a single 50W solar panel and to a 240 AH 12V battery array. The multi-meter reads 12.1V at the battery terminals, 13.5v at the terminals on the MPPT and the software reads 13.5V. Consequently, the batteries are always in float and no charge is being given to the batteries. Fuses are both OK and I have the mppt connected to the battery isolator.