my Multiplus II 5000/48/70 (230V) is running offgrid from a month now, and it seems everything fine.Actually my system is quite simple: MP2, 2 MPPTs, CerboGx and Seplos Mason 15Kwh.
All home loads are on the AC-Out-1 (critical loads) port while AC-Input port is grid connected but ignored using an Assistant setup: 1 general flag and 2 programmable relays for on/off logic switch based on SOC percentage.
I am wondering if I can add a 300w microinverter (that I already own) that I bought from amazon during one of my first solar test.
I read about a parallel connection of the AC-port of microinverter and the MP2 AC-Out port and an addictional setup I have to add to the MP2. Anyway I am a bit confused on how the frequency shift system works and I really don’t know what will happens if or when the AC-Input (from grid) is enabled. I’m also worried about messing up the system that now is working very well.
Any link, video, tricks and/or suggestions will be very appreciated.
On the Multi, you will need to enable the PV inverter assistant or ESS to be able to do it. The assistant will have defaults for the frequency shifting parameters to control the micro, assuming the micro can do that. You will parallel it with the AC1 output and you will need an energy meter compatible with your Cerbo such as the Victron VM-3P75CT. It can support single, dual, and three-phase systems. It works well. My suggestion would be to contact your local Victron distributor or installer, buy the energy meter and some support from them, and you’ll be good to go. Best of luck!
Andy from YouTube’s Off-Grid Garage channel has a video of him testing a grid tied solar inverter with his Victron based system. Search Andy’s channel for Charging my battery from almost anywhere.
Due to non-branded microinverter, it is mandatory to find out by available documentation or diy trial and error, if is capable of power derating on frequency change.
Many branded grid-tied inverters will start to react at 50.20-50.40Hz and shutdown at 52.60-53.20Hz.
Without reaction to frequency shift, the MP2 will not be able to control your microinverter.
Another idea would be to tie the microinverter on the AC1 through a contactor and activate it, from MP2, when battery SOC is below 80% and high household consumption.
The greater advantage of a grid-tied inverter in a Victron environment is posibility to direct use 230V AC energy.
If microinverter is not responding to frequency shift, except ON/OFF, battery is almost or 100%, no significant house consumption, the surplus energy will most likely force your MP2 to disconnect.
I’ll follow your suggestions and links, and maybe i’ll come back for other questions.
In the mean time I retrieved my amazon order just to check the model of my icroinverter.
In the manual I found no mention about frequency shifting but someone else but someone else might have used it.
Adopting another/opposite approach what would be your suggestions for a brand new microinverter that match perfectly with a Victron MP2 inverter?
Hoymiles is what I use and they are fully compatible with grid-tie use and support frequency shifting from Victron. They sell Euro versions and work really well. Have fun!
