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Paul B avatar image
Paul B asked

Multiplus 48/5000 and ESS and PV Inverter export PV power issue

This is a new installation and the first time I have done a PV system. and its been live two days now

  • I have the PV 5000w solar inverter that will turn off by frequency at 53 Hz (this is changeable)
  • The PV is connected to AC1 out
  • Battery bank is Lithium Phosphate 48 Volts 10Kw
  • Multiplus 48/5000-70
  • Panel size 4.5Kw
  • Grid connected to AC1 in

Problems I am having

  1. I have turned off export to grid but export is still occurring
  2. I have set battery charge limit to 1000w but I only want this to be if drawn from the grid if possible.
  3. I have said yes to PV power in ESS and changed the frequ to off at 53hz
  4. I cant see the Hz changing if I have excess PV power nor does the battery charge rate increase as all excess power is being exported, (even with export to grid set to off

Other bits I would like to do

I only want to charge or use all the solar during the day to charge the batteries and override the max charge rate rate if there is PV power available as the day progresses


otherwise everything is working well

More testing twomorrow



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3 Answers
michael2019 avatar image
michael2019 answered ·

How can I stop returning power to the grid from the PV Inverter?


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boekel avatar image boekel ♦ commented ·

You can only do that if your PV inverter supports zero feedback, or if you disconnect from the grid when your batteries are fully charged.

But...please make a new topic for this question, and give all info about your system (what components, where connected, etc.

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boekel avatar image
boekel answered ·

You can't change the grid frequency (ok...theoretically maybe)

so You'll have to use a PV inverter that can be controlled by the Venus (like the fronius range), or you'll need to disconnect the grid when the batteries are charged / only connect the grid when batteries are getting low. so the inverter can create an Island where it can control the frequency.

Best solution is to use MPPT's for these situations.

Sorry Paul but this is basic knowledge any installer should have!

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Paul B avatar image Paul B commented ·

Hi Boekel. I don't work in this perminant grid connected area usually and have not done grid PV connections before, but learning by doing my own house, so sorry for the stupid questions.

I mainly do the marine area and this sort of perminant grid connection never occurs

I get the point re the Island however, I did think the inverter did this itself when needed, but installing a grid shutoff control relay is a option


are there any other or better ways ????

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boekel avatar image boekel ♦ Paul B commented ·

You don't need a grid shutoff relay, the Multi has one built in...
use the 'general flag' assistant to ignore AC-in, than I'd use the 'generator start / stop' assistant to define the circumstances AC-in should be ignored. (basically, use the grid as a generator when batteries are running low, (voltage and/or SOC).

You can also use the Venus for easier control of generator settings, then wire the relay output of the Venus to an input on the Multi.

Whether using ESS is the best solution here is also the question.

If you want to keep it simple and reliable: use DC coupled PV.

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Paul B avatar image Paul B boekel ♦ commented ·

Thank you, That has helped a lot

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masi avatar image
masi answered ·

Hi, it seems it is a general issue in software. The system react with 40-50 seconds delay when condition changed. In my case I have "zero feed in" ON, when the pv production is bigger than consumption it has to start charging the battery, but because of that delay zero feed in is faster and the system reduce the power instead to charge the battery. Another case is for ESS system when grid is off, the battery is fully charged and a big amount of pv energy surplus. The system must start to increase the frequency in order to reduce the power. Again I measured 40-50 seconds up to the system reacted, mean time the voltage on the battery increase a lot. Can someone from Victron let us see the software logic, please?

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