question

michelp avatar image
michelp asked

multiplus ii frequency shift

I have this install in mind, on previous asking on member says, when the battery are fullfilled a frequency shift occurs to disable the PV to AC inverter.

What appends if i have load on AC connected, is it driven by the battery till they reached a certain level then increasing cycling on it

Or even if the baterry are fullfiled (for the time where there is no sun) my solar pannels can drive my load

I try to use ApSystem QS1 micro inverter

And use AC_out1 for both loads and PV micro inverters

Multiplus-II
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5 Answers
Paul B avatar image
Paul B answered ·

Hi,

You will need to setup assistants to drive the Freq shift settings.

https://www.victronenergy.com/live/assistants:how_to_add_and_configure_an_assistant


Note that if the grid or generator are connected then the inverter frequency shift cant occur,

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michelp avatar image michelp commented ·

I have read the link but i am a little confusing what kind of frequency shift behaviour i must set to:

Send power from my PV inverter to the battery and to the loads if the battery is not full

Send power from my PV inverter to the loads if my battery is full

Send power from the battery to the loads when the PV power equals 0


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russ avatar image
russ answered ·

I am planning to implement micro inverters also. In discussions with the supplier renesola we realised we can set each inverter to a different cut-off frequency so as the multi moves frequency inverters will cut off progressively to match the load.


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michelp avatar image michelp commented ·

Russ,

I am not specialist on Multiplus-ii, and i don't undersant why this situation frequency shift occurs because for me the charger part of the inverter charger may use a max current (C/10,C/5...) to fullfill the baterry limiting the power sink by the charger.

On the other hand the PV-inverter adapt itself to the power need it's a generator no needs of power no power output from them


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michelp avatar image
michelp answered ·

@Russ intresting aproach, in your wording you says frequency shift occurs to match the load, in others case guy's says frequency shift occurs because battery are fulffiled (the load change also)

Frequency shift for load adapt take sense

I am looking if it is possible to change this on mine,

And also in case of much power as needed perhaps the micro inverter can go to no-optimised power point on the PV side to adapt itself is power to the load


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Hugo Russouw avatar image
Hugo Russouw answered ·

Frequency shift can only take place when no grid is available. You can not change the frequency if the grid.

So this will only work for an off-grid system or when the grid fails.

The Multiplus uses frequency shift to protect the system in a way to limit the power of the PV inverter so be very careful when you change the frequency settings.

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Paul B avatar image
Paul B answered ·

Hi This is a posting of my ESS settings


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