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spudgun avatar image
spudgun asked

MultiPlus II Hub 1

Looking for some assistance please in relation to setting up a MultiPlus II with no grid feedback.


3KW MultiPlus II x 1

Venus GX x 1

PylonTech US2000B Plus x 2

MPPT 250/70 x 1

3KW PV Panels


Feedback to the grid is not allowed so ESS cannot be used. There is no Zhiel relay or anti-islanding in the system.

Critical loads have been connected to AC Out 1. The idea is to have the MultiPlus II in invert mode constantly and power these loads from the Pylontech batteries and the MPPT only.

The grid is very stable so grid failures are infrequent, grid should only connect to recharge the batteries if the batteries become 90% discharged.


I don't think the Virtual Switch "Ignore AC" would be suitable for this?

Is the best (and only) option to use Hub 1 Assistant which will prevent feeding to the grid?


Thanks for any help.

Multiplus-II
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boekel avatar image boekel ♦ commented ·

Why do you think the Virtual Switch "Ignore AC" would not be suitable for this?

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spudgun answered ·

If it would be suitable then I'll use the Virtual Switch?

I thought that the criteria for things to happen with the Virtual Switch is based on battery voltage and would be more suitable for a Lead Acid battery than a Lithium battery as the voltage on the Lithium battery does not vary as much as the Lead Acid.

What would you suggest would be the required setting for the Virtual Switch?

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boekel avatar image boekel ♦ commented ·

Using assistants will be better as you can use SOC as a value, read this:

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

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spudgun avatar image spudgun boekel ♦ commented ·

Thank you for the information. Is it as simple as in the below image or am I missing something else?

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ignore-ac.png (117.7 KiB)
boekel avatar image boekel ♦ spudgun commented ·

I think you have to invert the operation, now you:

-'start generator' (want to use grid) when below 20%, but as you use 'close relay to start generator' you actually ignore AC under 20%, so you have to 'open relay to start generator'

Also, sometimes you might want to use grid when loads are too high, to prevent overload of inverter (but when there is not enough loads to exceed the inverter limit this is not needed)

And...you need the 'Ve.bus BMS assistant' with the Pylontech batteries! (so the virtual switch couldn't be used anyway...)

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

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