How to find out the maximum PV generated power:

PV modules are subject to standard test conditions that are defined with particularly strict certifications (IEC, ISO). From idealistic radiance test conditions (1000W/m² at 25°C) result the provided voltages, currents and temperature factors that you can read from your PV modules specifications. Note that temperature plays an important role: an increase in temperature can result in modules generating less power. You must also consider all possible cable losses (PV installation) that can count for 3% and a 1% maximum in the mppt yield.