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Meno Himmelreich avatar image
Meno Himmelreich asked

My ESS is not working as expected. Some questions first.

kamepv.jpg

I build my system like seen above. There are some things, that are not working. Before I get in to much detail, I would like to know, if the system is even capable of doing, what I want...

  • If the battery is fully charged, is it possible to feed the DC MPPT power to the grid or the loads?
  • Is it possible to tune down the PV Inverter to feed "0" Watts to the grid, even if more PV is available and the loads are satisfied?

Thanx in advance!

MPPT ControllersESSVictronConnectfrequency
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3 Answers
Alexandra avatar image
Alexandra answered ·

@Meno Himmelreich

Feeding into grid from DC mppts. Yes Feeding loads also yes.

Zero feed in from fronius. Also yes.

Everything you need to know is in the ESS manual.

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Meno Himmelreich avatar image Meno Himmelreich commented ·
That leads to so many questions. ;) For one... Why isn't that working for me? I am going to dive into the manual, to see what i am missing. Fronius isn't showing the zero-feed, even with the latest firmware and modified Modbus settings as described in the manual. And as long as mains power is available, the Multis are in Mains mode and distributing just mains. The battery is not used when PV is unavailable... But mains recharges the battery... All of this behaviour is unwanted and nothing of the grid-setpoint or feed-in settings seem to change anything... Maybe I should start with fresh installation!?
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Alexandra avatar image Alexandra ♦ Meno Himmelreich commented ·

Are you trying to feed in?

Have you enabled Ac coupled PV feed in, the option will only appear after that is enabled.

controlling depth of discharge of the battery is found here. The grid will charge up to the set percentage in case of grid failure then stop.

You can also completely disable grid charging (or set it lower) on the grid tab in ve config for each inverter.


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Meno Himmelreich avatar image Meno Himmelreich Alexandra ♦ commented ·
Thank you for your suggestions. A proper Reset did the trick. now the system is working as I hoped for.
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Meno Himmelreich avatar image
Meno Himmelreich answered ·

1658654836992.png


@Alexandra

One further question. PV is producing 4kW, loads consuming 1.4kW so there is a PV overload of 2.6kW from which 1.8kW are used to charge the battery.

Could the "missing" ~790W considered to be the AC-DC inverter loss of the Multis?




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Alexandra avatar image Alexandra ♦ commented ·

@Meno Himmelreich

790W will include the power consumption of the system, some lost as heat and some losses in conversion.

Do your batteries have comms with the system? Sometimes it is an assumed amount (so calculated not actual) going down to the batteries if it is not reported by the BMS or there is no shunt.

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Meno Himmelreich avatar image
Meno Himmelreich answered ·

Got that figured out as well. I relied on the BMS, but now I have installed a Shunt and the values seem to be right.

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