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mbelgil avatar image
mbelgil asked

Safely connect generator relay to Venus GX

Hi, I've got an off-grid solar/generator system as shown in the photo below (not set up by me!).

Currently the Inverter and BMV-700 are both connected to a relay from the generator, and they can both start/stop it using their own independent conditions. I have a Venus GX installed but currently its not connected to the generator, and just monitors what the Inverter/BMV are doing.

Ideally I'd like to connect the Venus GX to the generator relay as well so that it can be controlled fully, and remotely more easily. I think I've figured out where to take the relay wires from in order to do this (see second photo).

My question is this: what is the correct way to wire to the Venus GX. I understand that 'Relay 1' is for the generator, but I don't know which wires go to which terminal (NO / COMM / NC).

Secondly - how do I do this safely without risking shock or injury? (i.e. how do safely disarm the wires before I re-connect everything up).

Thanks,

Michael.


GeneratorVenus GX - VGXRelay
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

With the Venus GX you don't need the relays from the BMV and Phoenix.
You can set all conditions in the generator start/stop settings of the Venus
(SOC below 80% or power over 1500W for 10sec -> ON | SOC over 95% or power less than 500W for 2h -> OFF)

If you have to use COM and NO or COM and NC depends on what the generator need to start -> manual of the generator or you take a look on what the BMV and the Phoenix are doing when they want to start the generator.
(do they open or close the relay?!)

For the wiring you should hire a electrician. You installation is pretty wild and without being there to see which were the wires comes from/goes to it's hard to say were you have to connect the Venus GX relay.

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mbelgil avatar image mbelgil commented ·

Hi @M.Lange, thanks very much for your response, very helpful. After looking at this for a while it's starting to make a lot more sense to me. I can now also see that a power socket goes directly to the relay junction box, so it seems clear that I should unplug that before doing anything!

I also know that when the relay is closed the generator is on (and open=off). Does this mean I should be using COM and NO ('normally open' right?).

My final question in this case is: which connection is live and which is neutral - COM or NO?

Thanks!

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Matthias Lange - DE avatar image Matthias Lange - DE ♦ mbelgil commented ·

Don't connect booth L and N to the relay this will give you a short circuit in the moment the relay switches! (and properly destroys the CCGX relay)

As I mentioned first and Daniël also, if you don't know what/how to do you should hire an electrician. 230V can be lethal!

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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

@mbelgil

Please! get an electrician to re-do -all- AC wiring, and double check all DC wiring.

This is -unsafe- and should not be used.

Please don't work at it yourself also, without basic electrical knowledge, please get help with this.

Do Not Use as is.

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mbelgil avatar image mbelgil commented ·

Hi @Daniël Boekel (Victron Energy Staff),

Thanks for your response, much appreciated. I'm definitely very conscious of the dangers and am not going to do anything silly. Unfortunately I'm quite remote and due to the lockdown at the moment it won't be possible to get an electrician round for quite a while.

My current setup works so there's no urgency to risk making changes - I was just hoping to be able to get the Venus GX in control of everything, but if I can't do that its not a problem for now.

It would be useful to know how a relay should be wired to the Venus though - I can't find any information online about this and the Venus GX online manual is very basic!

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