Our 18-60V grid-tie microinverter requires a starting voltage of 24V and has an operating range of 18V-42V (Vmp). Please note that the Voc of the solar panel should not exceed 60V. It is not recommended to use 12V solar panels with a Vmp of 18-20V and a Voc of 20-24V, because weak sunlight may cause the operating voltage to drop below 18V, causing the inverter to work unstable and be damaged. Instead, we recommend using a solar panel with a Vmp of 30-42V and a Voc of 38-60V for optimal performance. Regarding the heating problem of the inverter. This is normal phenomenon. All electronic devices generate heat during operation. The inverter uses aluminum alloy material. Metal can conduct heat better. The inverter also has over-temperature protection if the temperature is high. Then the inverter will automatically reduce the working output efficiency. After cooling down, restart. It is recommended to install the inverter in a ventilated, dry and cool place. After a large amount of customer data feedback, the inverter cannot work because the DC or AC fuse is damaged. When you encounter this problem, we can send you accessories for free. And give you maintenance video instruction. You can easily replace it.