Andrea C

Thank you all for the answers and ideas. Yes, I did ask a Solar PV company about systems that use the excess production from the panel (I suppose what here you call dump controller and diverter) - They quoted 800£. I checked the Solic 200 diverter (thanks @Marvin) - 200 £ on ebay. My immersion heater is far from the PV switch, so it needs to be wireless communication. As @Radian said, I was trying to find a cheaper solution. My idea was: create a rule that says: if the light sensor detects lights over a threshold, then switch on the immersion heater; this would work even below the 3 Kw demand level. Still not sure which switch to use and I do not know if this one (https://www.timeguard.com/products/wifi/wi-fi-switches/fstwifitu-wi-fi-controlled-fused-spur-tuya-edition) is compatible with IFTTT. @TonyT you suggest a switch-bot right?

Good morning, I have solar panels in my roof, installed 12 years ago. I would like to automate the production of hot water from the immersion heater, when the sun is out, without spending too much money. My idea is to use a IFTTT applet and couple it with a sunlight sensor and a wi-fi operated fused spur. I found the sensor (https://cablematic.com/en/products/smart-wifi-light-sensor-compatible-with-google-home-alexa-and-ifttt-AN13500/?utm_source=pocket_saves) I am not sure of which fused spur to use - I find wi-fi swithces, but not a fused spur adapted to an immersion heater. Any idea? Thanks in advance