Suntech 275w – This module is perfect for both residential and industrial roofs and has been tested in many climates. The 25 year warranty is also included with this module. Remember that the 250w – 290w range are almost always 60 cell modules, which are not suitable for battery charging except with a MPPT controller. In battery language, they are nominal 18v modules. If you use a PWM charge controller with these modules, you will harvest approximately half of the rated power.