I have a 4kw system with Pylontech batteries, Cerbo GX, Multiplus II 5000 and MPPT RS.
It's been running for about two months and works great giving me zero usage from the grid, but it's summer here and I wouldn't have expected anything else. I.e. the available solar combined with the batteries is greater than my kWh needs.
I'm planning ahead for both my EV arriving and also winter, i.e. my kWh needs will be greater than my available solar.
I've enabled node-red and have an idea in my head but I'm on a very steep learning curve with node-red and I was hoping that someone else had already done what I was planning and I could just use it :)
The idea is as follows, hopefully it's fairly generic and can be used by others:-
I have a known household load which is fairly regular by hour.
I have a forecasted solar energy in kWh broken down by hour from the node-red solar-forecast flow. This uses weather estimates and my location to estimate the kWh per hour for the rest of today.
By taking the forecast energy for the rest of today, less the household load for the rest of the day I get the potentially available solar for the rest of the day. If I add to that the kWh available in the batteries I get the total available for the rest of the day.
I would then like to use this available kWh based on some rules. Each hour I would re-estimate the rest of the day.
All of this would of course need to be fully automatic using e.g. node-red
My two main loads today are a 3kw immersion heater (water heater) and an EV. As the EV may try and take a kW close to the maximum of my Multiplus, I would like to have this on a timer of some sort, e.g. a maximum of 30 minutes at peak load before a 5 minute cool down. The two loads are connected to SonOff 25amp PWR3 boxes, these in turn are enabled/disabled by SonOff MiniR2 switches which connect to the two Cerbo relays.
The rules may be:-
If EV is connected and available kWh is > amount needed to run immersion heater until the tank is hot, then use the available kWh to send to the EV.
I'm hoping I'm reinventing a well made wheel here and someone can point me in the direction of some pre-made flows :)