So, mppt in parallel? hmmm, never thought to compare that. Not much 'extra' voltage there to work with, but I guess it would be a fair comparison? I guess it's no different than simply running each controller off its own single 12v panel, like in that marine test?
I've been thinking about your results, and was wondering if it's not so much a matter of "measurement error", but one of "data inaccuracy", due to meters/measuring devices rounding up or down? I noticed with the Tracer's mt50 meter, it only goes to one decimal place for voltage... and my dmm does likewise, when in its 200v range, vs. its 20v range, which goes to two decimal places. As a result, it often appears the Tracer is doing better than 100% efficiency.
