I am hoping for some insight on this from the career electricians and/or others here who are versed in the trade. I have an empty lot with no utilities and have been using a battery powered pump to pull water from a channel for irrigation. I picked up a pair of used solar panels and a charge controller to recharge the battery. I have tested this with everything laying on the ground, functionally, it works great for what I need to accomplish. Now for the question- Since everything is stand-alone DC which is not tied into any structure or system, does this fall under the NEC?