I present here my ideas / design for my home built solar PV dump load controller, based around an Arduino microcontroller.  It is not presented as a "design" but rather ideas for you to use or adapt as you see fit.   This is my MK 2 design.  For background, my Mk1 version was based on a design by Eric Ward in Jan 2011 which used a single current transformer, and sampled the ac waveform a number of times per cycle to determine if the measured current was being imported or exported.  Thi