The PTLevel and Solar Panels
Both the PTLevel WIFI and PTLevel Long Range Wireless can be utilized with solar panels; however, you must provide the complete solar package (batteries, solar panels...). The PTLevels do not have charging capabilities built into them.
To size the solar system accordingly, check out these articles:
Out of both of the PTLevel options, the Long Range Wireless the better option for solar since it's solar requirement (power usage) is much less. Also, it can utilize the battery area for power backup. The solar panels will not charge these batteries.