When it comes to determining the best size of inverter for solar panels, it depends on the specific power requirements of your system. Generally, you'll want an inverter on solar panels that can handle the maximum power output of your solar panels.
A rule of thumb is to choose a solar panel power inverter with a capacity 20% higher than the total wattage of your solar panels. For example, you’d better use at least a 240w inverter for the 200w Anker 531 Solar Panel to allow for better performance and accommodate potential increases in power production. However, it's always recommended to consult with a solar professional to ensure you select the optimal solar panel with inverters for your specific needs and to maximize the efficiency of your solar panel system.