A bank of gel cells is not so tolerant of such high voltages, Pv Wire and you must ensure that your controller keeps the voltage at a more affordable range than the lead acid batteries are prepared for. It is a choice to keep a limit of approximately 14.2 volts with gel cells. An intermittent small overcharge may not hurt, but better to be safe than distress...
Then you receive into the multi conductor power Cable s used for the same reason. They offer power to distant outdoor locations. The multi conductor cables are quite similar with regard to an extension twine. Extension cords are for smaller applications like generators and personal home wear. These cables are called portable cord and SOOW Rubber Sheathed Cab...