Its unclear from the specs what that circuit will do in low light conditions.
It appears to be a standalone MPPT converter which isnt reliant on a battery for its operation, so relies on the solar panel being able to provide enough power to power it , which may not be the case in low light conditions.
If you really want some kind of MPPT, look for a circuit which is specifically designed to charge a battery, and such a circuit wont need a reverse blocking diode as the above circuit does.
Also when looking for a MPPT designed to charge a battery make sure the MPPT is designed for the correct battery chemistry.
BUT, as previous posters have already indicated, define you need, in particular how much power is going to be consumed by whatever you ultimately want to power with your solar setup.