In my setup I have a MP2 3000 - Using the Primary AUX Relay I switch a second Inverter which permanently runs at full power (Less than my base demand), the relay is switched based off Battery Voltage
Now I have adjusted my setup and want to make use of the ESS’ ability to charge the battery when Tomorrows Grid Power happens to be much more expensive than todays and my Battery is not full towards the end of the day. This works perfectly fine, however in this case I would ofc like to disable the AUX Relay and thus 2nd inverter as otherwise that is just burning power when I otherwise dont want to produce anyways.
Based off my research, this is not possible and the Relays cannot be switched based off negative / charge power which would’ve been the simplest solution (Unless I’m missing something?).
Another option I’d be fine with is manually switching the Aux Relay in my own Code - I control the ESS myself via VE.Bus, so if it is possible to control the Relay via VE.Bus I would love to know about that
If someone should at some point have this same issue and need a solution (The simplest one), heres what I came up with:
I dont use the SOC Tracking of the MP2, I have an external BMS. So what I will do is enable that, but tell it the battery has a Capacity of 1Ah - I can then switch the relay (and thus 2nd Inverter) off when the SOC is >50% and off when its <50% which will happen very timely related to turning on / off charging
Edit: I have now tested this solution and it works good enough for me.
Unfortunately I came to the conclusion that I would rather like to enable the relay and thus fixed-power secondary inverter whenever the ESS produces more than X. With my previous hack setup I noticed that things would oscilate because as the sun rises my simple PV / Microinverters would cause the ESS to produce less and less power until eventually it crossed over to charging from grid. This would then ofc turn off the 2nd Inverter which would cause the MP2 to produce again, which would ofc soon after turn on the 2nd inverter again.
Now I could obviously increase the relay locker a lot but all of this is really hacky and it would be much better if I could just toggle the aux relay based off ESS production
Hi, i have secondary inverter too, i use shelly PM to switch it on and off, depend on data what i get from mqtt server. And script can use SOC, solar production, voltage, inverter status, etc.
I do control the ESS manually by sending VE.Bus commands myself from an ESP32, so I could also do that myself with a seperate relay but I think not being able to use the current ESS setpoint as a relay trigger is a big oversight seeing as there is one for AC Load