Good day,
I have a 3F island system with multiples. I am looking for a solution to turn on the 3F 6.6kw water heating in each phase depending on the available power on the roof...
So, if the power is available at 2.2kw, turn on 1F, when 4.4kw turn on the other phases, etc. and adapt according to the sun that shines so that the battery is stretched and uses the sun at 100%
Thank you for any tips and advice on how to solve it, either externally or via node-red. :)
Power availability from solar is not directly measurable, unless you apply loads and measure what you get, which is basically what an MPPT does.
One possible approach would be to use an irradiance meter/light meter, calibrate that against panel power and use that to switch relays. Probably needs micro controllers and programming. Also smoothing/averaging to allow for cloud effects.
But assuming that by 3F you mean 3 phase, you're going to have to bring total output from solar into a single point (i.e. battery bank) and switch on a phase at a time. This will lead to imbalance, but I guess you're able to handle that.
What if you configured the Battery % SOC to turn on a relay, which enabled one phase of the load? Phase # 1 turns ON at >85% SOC. Phase #2 turns ON at >86% SOC. Phase #3 turns ON at >87% SOC. If there is is enough PV Power then that phase stays ON. If there is not enough PV Power then the Battery % SOC will drop and that phase will turn off. Adjust the Battery % SOC values, as needed.
Take a look at the new forecasting feature, with Node-Red you may be able to get what you need.
https://community.victronenergy.com/questions/216543/new-vrm-feature-solar-forecast.html
Hope it helps
