Renogy 200 Watts 12 Volts Monocrystalline Solar Bundle Kit w/ 100w Solar Panel,30A Charge Controller,9in MC4 Adaptor Kit,A pair of Branch Connectors Two Renogy 100-Watt monocrystalline solar panels can be connected in parallel by a pair of branch connectors. The charge controller has been upgraded to Renogy' s new 30A PWM Negative Ground Charge Controller -- the Renogy Wanderer. The system can be extended up to 400-watt in parallel connection. 4-Stage battery charging process for a rapid, efficient, and safe battery charging Negative grounding controller ensures the broader off grid applications and safety, especially to be used on a vehicle which has battery negative on the chassis. 25-year transferable power output warranty on panels and 1-year warranty on rest of the kit components.Optimum Operating Voltage (Vmp): 17.7V