OP
old grouser
I'm an idiot (in the Greek sense of not being one of you guys who understand electrics) but I do have a solar pv system and a conventional 3kW immersion heater, and I recognise that there is an obvious need for a system to store surplus electical energy as hot water. So there's an obvious need for some sort of switching/power reduction device of the sort you are collectively developing and discussing, and there's no reason why it should be particularly expensive, since (forgive the idiot language) it's really just an intelligent switch (I could do it myself if I sat in the airing cupboard all day with my Sunny Beam, waiting to turn on the immersion heater at those magic moments when the generation reached 3kW. Of course, it would be better if I could divert just the available surplus generation... but even I can see that this isn't an insuperable problem....). What is clear to an outsider is that there will be a sizeble market for this sort of product in, say, five years' time; that it's understandable that people would want to protect the value of their ideas; and that it's laudible that people should want to benefit us all by producing a collective, open source solution. Probably the commercial model will win; but it doesn't have to be patented. Volvo developed the 3-point seat belt, and deliberately didn't patent it. It's a commercially viable idea nevertheless. Lots of people make them. Presumably they all make a living from them. I hope that between you you'll produce a cheap, safe, viable and marketable solution soon, and that everyone will benefit. I'm impressed that you are trying...