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florianro avatar image
florianro asked

ESS: Using AC OUT 2 for water heating, but only when battery is full and enought solar power is available

Hello,
I think I've seen this scenario in an explaination video but I cannot find it any more. I'm talking about an ESS System with Mutliplus 2 and Venus GX.

I want to do the following:

1) When I have enough solar power left, so the battery is full and I would feed into the grid more than 3000W

2) Then activate AC Out (a heating element in a boiler) if the boiler temperature is under a certain value.

Is there a possibility to do that? If yes, how?

thanks,

Florian


Multiplus-IIESSVenus GX - VGXac out 2
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2 Answers
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Rob Duthie answered ·

Hi

Yes you can, There are many ways to do this, set a temp switch to trigger a relay out on the GX and have it set to alarm mode to turn on the relay contactor for the heating element crude but will work.

You can rename the alarm mode to water heating if required.

Do you have a Fronius type grid tied inverter as well to be AC coupled ? If you do it is even easier

As i have mine set up to see if i have surplus PV power and battery is charged after the loads are taking care of etc. and it turns on the heating element via relay contactor.

Do you have grid tied inverter as well? or you just using the mulitplus2 as the grid tied inverter.


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florianro answered ·

Hello,

Yes the fronius converter is grid tied and it is AC coupled. And the Multiplus2 is only charging the battery and discharging it when the solar power is to low...

So in Venus GX I can see the Fronius production power, the power meter (how much power I'm consuming from the grid) and the battery loading power (and the battery level).

So can I control AC OUT 2 directly or do I have to use a relay?

thanks,

Florian

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Rob Duthie avatar image Rob Duthie commented ·

Hi

You use the Fronius as the control as it has aux output relay for controlling heating loads, you just set the parameters to when it sees surplus grid export and control from there, no need to use the Multiplus2 to do this at all as it manages the rest.

This is what i have done and works perfectly. As i have the same setup with a Fronius and Multiplus2

Just need a small 12v relay to control the bigger contactor to switch the heating elements.

Regards

Rob D

NZ

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