I have an offgrid victron installation and would like to use the PV headroom to control a boiler analog with mqtt. I built an MQTT analog controllable AC boiler. I have PV using victron MPPT’s, gx with node-red, Batteries and Multiplus with only AC out connected and I run DVCC to limit battery charge current. But I do have a lot of spare PV energy in the summer. Now I would like to cinvert that into hot water. I am a software engineer and I am thinking about what logic to use for my application. I could setup a slave PID controller in Node-RED to 2 amps less than the DVCC setpoint that puts axtra load on the multiplus to increase direct consumption but that will only work in the Bulk charge step of my MPPT’s. Any suggestions?
Just use the relay assistant in the Multiplus based on Soc to switch AC2 output on and off!
Ewky, a relay is no analog controller and has nothing to do with measuring/calculating the headroom in solar power.
Hi Ludo, please explain how setting absorb and float voltages has anything to do with calculating the available solar power headroom?
Battery charging curve is set properly and doesn’t need te be changed for my application…
If you interested i setup a node red based PID controller that takes the excess power and proportionally heats the water. It all works on a raspberry pie and uses the native node red in the inverter to send MQTT information to it to drive a 0-10 volt 240 v proportional controller on the mains.
Yes it would be nice to have a look at your node-red program. Could you export a json and send it to me? or take snapshots of your software? Curious on the details of how you did yours.