To chain two or three Boulder Solar Panels together, plug the blue ringed connector from one panel into the input connector or input port of the next panel, using the charging cable from the final panel to connect to your Goal Zero Yeti or Sherpa.
If you’re chaining more than three Boulder 50 Solar Panels together, or any configuration over 150W, you will need to purchase the 4x 8mm combiner cable from Goal Zero.