One of the problems with monitoring systems is that there not always that reliable. But it depends on how much you have to spend if your looking at the residentual market then the most relable monitoring device we have found is the SMA bluetooth. Which is a device that is powered by the sun and can sit in your window ledge moniting the PV panels on your roof. alot of opther systems we have found that there has been issues in receiving stats on the pv panels. What you need is something that is reliable. Don’t forget you have your panels for 25 years plus.