question

scraggs avatar image
scraggs asked

PV preference over generator output

Hi
I have searched the site as I am sure I have seen this asked before.
Now we are starting to get some bad weather my PV input has reduced enough for me to need to run the generator every few days for a few hours until I finish the panel install, The problem I am having is that when the generator is running the ac inverter gets throttled and I am losing whatever is being generated by the solar and the generator is obviously working harder than it needs to be.
Is there anyway this can be set to use all the pv and then supplement it with the generator.
This is on a off grid setup, I have 2 assistants, PV inverter support and generator start/stop.
Any help would be greatly appreciated.
Setup is
930ah (C5 rating) IPzS 48v battery setup, using custom profile in charger
Victron multiplus 2 48/8000/110 inverter
fronius AC 8.2-1 inverter on AC1 out
Smartshunt 500
Cerbo GX

Generator
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1 Answer
kevgermany avatar image
kevgermany answered ·

Usually setting the battery voltage slightly higher on the PV side than the generator side would help. Not sure if it's possible here, worth checking. Don't go outside the battery maker's voltage recommendations.

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David Gould avatar image David Gould commented ·

Scraggs is connecting the fronius AC 8.2-1 inverter on AC1 out, therefore AC coupled not DC. I run virtually the same setup in an off grid and dont see that issue. A few thoughts maybe..

Is the generator reaching you max charge current and throttling the froniuos back.

I use the cerbo genny start stop when i have large loads on to save charging the battery then discharging as it is more efficient.

I also use the cerbo genny start stop quiet hours so i only run the genny at the end of the day if not enough in batteries

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scraggs avatar image scraggs David Gould commented ·

@David Gould thanks for the reply.
Yes the generator is getting to maximum charge current then throttling the Fronius back and supplying everything.
Like you I am using the Cerbo to control the generator.
At the moment it looks like my options are either dump the PV which is mad thing to do or run the genny in the dark.

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David Gould avatar image David Gould scraggs commented ·

Do you use anything like NodeRed on your cerbo?, you can control the genny so that it only comes on when there is no / low solar or the batteries very low or load high? I do things like turn the generator on when the kettle comes on so that high loads are covered

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scraggs avatar image scraggs David Gould commented ·

No I don't but I will look into it.
I was hoping this would be fairly straight forward to change which takes priority.

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