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diederik avatar image
diederik asked

Turn grid on/off

Hi,

I have a Multiplus-II GX and working on a Node Red flow to control my setup.


The PV inverter is a Sunny Boy 3.0. When the grid fails I switch the Multiplus to Inverter only. That way the Sunny Boy can keep charging my battery.


The problem is when there is a lot of sun and the grid reaches 253V, the Sunny Boy will stop working. My idea was to turn the Multiplus to Inverter Only too. So far so good. But, when the grid drops again to, let's say 230V, I'm not able to measure that voltage. And I'm not able to turn the Multiplus back on.


Any ideas how to deal with this?

settup.png

Multiplus-IIgridvoltage
settup.png (58.2 KiB)
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matt1309 avatar image matt1309 commented ·
Hi @Diederik


Is there a reason you're not using ESS and having the sunboy wired on ACOut side of inverter? Assuming sunnyboy supports frequency shifting it'll work without needing manual control.


Is your setup safe. What happens to sunnyboy power output when grid goes down and you've turned on inverter only mode and the batteries are full?

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diederik avatar image diederik matt1309 commented ·

At first I had only the Sunny Boy and wanted to be 100% sure that I always can charge the battery, even without grid.


About your second question, to be honest, I have no idea. Won't it just be balanced?

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3 Answers
Duivert NL avatar image
Duivert NL answered ·

hi, why dont you use ESS, then everything works automatic, also if grid voltage is above settings in multiplus grid, then it disconnects and runs in inverter mode automatically

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diederik avatar image diederik commented ·
This is all pretty new to me.


I'm using ESS. Where can I check the settings that it will disconnects automatically?
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Duivert NL avatar image Duivert NL diederik commented ·
you can set that up in VE config - grid


also: is your sunnyboy PV considering the factor 1 rule?

and have you setup the frequency shift for the sunnyboy, thats what matt1309 meant

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sharpener avatar image
sharpener answered ·

Eastron multifunction meter on grid connection would have many uses inc measuring the voltage, interfaced via ModBus.

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daza avatar image
daza answered ·

@Diederik as everyone has said just use ESS on another not OP I would look at your input voltage as a separate thing if in the UK get your DNO to sort out the over voltage that’s if it is as they deem 253volts acceptable limits.

I got mine tapped as my Shelly EM logged multiple spikes going back a year or so where it got to 256volts at around 2pm and another at 8pm took them months to sort it and a lot of call and 6months worth of Shelly data and a week of there device being installed.

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diederik avatar image diederik commented ·

I tried to be as detailed as possible when asking this question but now I realize I forgot some details.


I use ESS, DVCC and Node Red to control things.
So when the grid is off or I put the MultiPlus in Inverter Only, ESS will do some frequency shifting and all will be safe.

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Duivert NL avatar image Duivert NL diederik commented ·
yes, if everything is set up right (ESS, PV and freq shift, 1 factor rule) and you let just ESS run the system, it will work fine


if you turn it to inverter only ess and the rest can work unexpected


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Related Resources

MultiPlus-II Product page 

MultiPlus-II Manual

Multiplus-II GX Online Manual

MultiPlus-II 230V Datasheet 

VE.Bus Error codes

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