> This topic seems to be broadly misunderstood. It is 100% verified fact by both myself and others (including university researchers) that diode strings can produce more heat (or watt-hours, BTU) from a given solar panel than a bare resistance element.
In some of my early experiments with little radio transmitters some 30-odd years ago I managed to burn my fingers to an astonishing degree with little plastic transistors like ZTX300s and BC548s.
I remember my late father also commenting around that time "How come a 2N3866 which is rated for a couple of watts can get so hot it melts all its legs off when it's running off a half-flat PP3 battery?", astonished as yet another 2N3866-based amp got a bit lively and melted its legs off despite only running off a half-flat PP3 battery.
So yes I can believe a string of diodes would be a more effective heater than a resistor.