question

sasquatchza avatar image
sasquatchza asked

Relay switching on PV generation

Hi Everyone,

I have a Multi2 inverter, with a 250/100 VE.CAN MPPT and a Cerbo GX.

I would like to switch a relay based on the current PV generation (Watts or Current will work, but not Voltage as this does not relate to available power very well).

Idea would be: [If (PVGen > 1000W for > 5 min) then Relay on for 5 hours.]

This relay will then switch my pool pump on. This would ensure that the pool pump will only run if the sun is out - I do not want it running while it's overcast or raining.

I would prefer not having to rely on SoC as I want the pump to switch on before the batteries are charged up. I cannot find a way to do this - please point me in the right direction?

Thanks

Squatch.

RelayAssistants
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2 Answers
shaneyake avatar image
shaneyake answered ·

You can do this relatively easy using NodeRed running on the Cerbo.
it is in the large features menu. You can then connect together some nodes to control the Cerbo relays. I wouldn't directly run a pump on those relays tho.

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sasquatchza avatar image sasquatchza commented ·
Thanks. I was hoping to be able to do it with the original Cerbo software. But if I don't get right, I will try Node Red.
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shaneyake avatar image shaneyake sasquatchza commented ·

NodeRed is now included on the Cerbo so you don't need to install anything else and is definitely your best beat for trying to do what you want.

The flow you want is very simple, System PV -> Switch Node with greater than 1000 -> Change node, change payload to 1 -> Cerbo Relay node.
You then also need to add a split from Switch Node that goes into a delay node for 5 hours -> change node, payload set to 0 -> Cerbo Relay node.

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sasquatchza avatar image sasquatchza shaneyake commented ·
Oh, I see! OK, great. That will allow me to automate to my hearts desire!

Thanks

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netrange avatar image
netrange answered ·

You could try the "Generator" relay 1 function of the cerbo.
This is about the only function that is linked to timing relays.

Relay contact 1 on "generator" and then watch through the menu "Generator" ...
There are conditions and time functions ...

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sasquatchza avatar image sasquatchza commented ·
Thanks for the response, but the generator options don't list anything that uses the PV power being produced as a condition.. The only one that I can see that might work, is SOC, but that would delay the pump. Usually, when I get over 1000w in the am, I will continue to get good power until the pm and I would like to make use of that.
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